摘要:

Mendeleev Communications Electronic Version, Issue 6, 2001 1 Synthesis of a vinyl-containing analogue of bacteriochlorophyll a Andrei F. Mironov,*a Michael A. Grin,a Danil V. Dzardanov,a Kirill V. Golovina and Young K. Shimb a M. V. Lomonosov Moscow State Academy of Fine Chemical Technology, 117571 Moscow, Russian Federation. Fax: +7 095 434 8711; e-mail: mironov@httos.mitht.msk.ru b Korea Research Institute of Chemical Technology, Taejon 305-343, Republic of Korea 10.1070/MC2001v011n06ABEH001519 3-Vinyl-3-deacetylbacteriopurpurin was synthesised for the first time, and the esters of vinylbacteriopurpurin were prepared by the addition of alcohols directly to the reaction of bacteriopurpurin with p-toluenesulfonic acid.The search for new photosensitizers for the photodynamic therapy of cancer is now actively performed among natural chlorophylls and bacteriochlorophylls.1 These two pigment classes are structurally similar but bacteriochlorins have the additionally hydrogenated pyrrole ring B and the acetyl rather than vinyl group at the 3-position of the macrocycle.Such structural changes of bacteriochlorins cause a significant improvement in their UV-spectroscopic properties, particularly, the bathochromic shift of the Q-band to 770 nm.The introduction of an additional six-membered exocycle (e.g., anhydride) into the main macrocycle leads to a further bathochromic shift (to 818 nm) of the major absorption band of bacteriopurpurin (BP). The structure of bacteriopurpurin offers many ways to modify it chemically.2,3 Hence, BP was chosen as a key compound to synthesise various photosensitizers in the bacteriochlorin series.We improved the stability of purpurin 18 derivatives by the conversion of an anhydride exocycle into an imide one.4 We synthesised the N-hydroxycycloimide of bacteriochlorin p6 and demonstrated that the acetyl group is involved in the reaction of BP with hydroxylamine (as well as the anhydride ring) resulting in the formation of the corresponding oxime.The aim of this work was to convert the acetyl group into vinyl to improve the selectivity of BP reactions. On the other hand, 3-vinylbacteriopurpurin is structurally similar to purpurin 18, which allows us to use the synthetic procedures that we developed for chlorophyll a earlier.5,6 The vinyl group in the pyrrole ring A of 5a was obtained from the ¥á-hydroxyethyl group of 3 by treatment with p-toluenesulfonic acid (Scheme 1).The reduction of the acetyl group required temporary conversion of bacteriopurpurin 1 into bacteriochlorin 27 because the treatment of BP with sodium borohydride leads not only to the formation of an alcohol but also to the conversion of the anhydride exocycle into the ¥ä-lactone.8 Therefore, the anhydride ring was first opened by treatment with aqueous NaOH, which led to a hypsochromic shift of the Q-band to 770 nm.Triacid 2 was reduced by sodium borohydride to form alcohol 3 with an absorption maximum at 740 nm. We discovered that treatment of 3 with hydrochloric acid in dioxane led to the anhydride exocycle closing without affecting the ¥á-hydroxyethyl group of 4, while treatment with p-toluenesulfonic acid led to 3-vinyl-3-deacetylbacteriopurpurin 5a, which returns the major absoprtion band back to 783 nm.We found that, as opposed to the formation of free acid 5a in a chloroform solution, the addition of ethanol directly to the reaction mixture led to fast esterification of the propionic acid residue, which resulted in the formation of ester 5b.The carboxyl group seems to possess such an enhanced activity due to the formation of an anhydride with p-toluenesulfonic acid. Compound 5b was obtained in 45% yield and characterised by HRMS and 1H NMR spectroscopy.¢Ó The signals of the bacteriochlorin macrocycle meso-protons (10-H at d 8.55, 5-H at d 8.47 and 20-H at d 8.32 ppm) were assigned using the data of 1D NOE experiments.The irradiation of the methyl groups at the 2- and 12-positions of the macrocycle led to NOE observation at 20-H and 10-H signals, respectively, while the irradiation of the vinyl group ¥á-proton caused NOE at the 5-H meso-proton, which confirms their spatial proximity. Finally, we analysed the influence of substituents on the spectroscopic characteristics of the bacteriopurpurins and com- NH N N HN O H Me H O O O H HOOC H Me NH N N HN R H Me H COOH COOH H HOOC H Me 2 R = COMe 3 R = CH(OH)Me NH N N HN OH H Me H O O O H HOOC H Me 1 4 NH N N HN H Me H O O O H ROOC H Me 5 a R = H b R = Et Scheme 1 ¢Ó UV spectra were recorded in CHCl3 using a Jasco-UV7800 spectrophotometer.The 1HNMR spectra of CDCl3 solutions were recorded using Bruker WM-250 and Bruker AM-300 NMR instruments and the DISNMR94 software.The 1D NOE experiments were carried out using the NOEFAST program, irradiation time was 1.5 s. Mass spectra were obtained on a VISION 2000 time-of-flight MS instrument by MALDI with 2,5-dihydroxybenzoic acid (DHB) as a matrix. The mass spectrum of 5b was recorded using a Micromass Autospec mass spectrometer (EI, 70 eV, 200 ¡ÆC).Characteristics of the compounds obtained. 3: UV, lmax/nm (relative intensities are given in parentheses): 379, 400, 510, 740 (1:0.9:0.5:0.85). 4: UV, lmax/nm (relative intensities are given in parentheses): 364, 411, 536, 775 (1:0.8:0.6:0.6). MS, m/z: 584.2 (M+). 5a: UV, lmax/nm (relative intensities are given in parentheses): 364, 411, 539.5, 782 (1: 0.77: 0.35: 0.39). 5b: 1H NMR, d: 8.55 (s, 10-H), 8.47 (s, 5-H), 8.32 (s, 20-H), 7.73 (dd, 31-CH, J 12 Hz, J 18 Hz), 6.19 (dd, 32-CH2-cis, J 18 Hz, J 1 Hz), 6.11 (dd, 32-CH2-trans, J 12 Hz, J 1 Hz) 5.06 (d, 17-H, J 7 Hz), 4.25 (m, 18-H, J 7 Hz), 4.2 (m, 7-H), 4.05 (q, 175-CH2, J 8 Hz), 3.95 (m, 8-H), 3.56 (s, 12-Me), 3.25 (s, 2-Me), 2.4 (m, 172-CH2), 2.37 (m, 81-CH2), 2.0 (m, 171-CH2), 1.8 (d, 7-Me, J 7 Hz), 1.7 (d, 18-Me, J 7 Hz), 1.16 (t, 175-Me, J 8 Hz), 1.1 (t, 82-Me, J 6 Hz), 0.5 (s, NH), 0.0 (s, NH).UV, lmax/nm, (e¡¿10.3): 365 (41.2), 414.5 (20.4), 541.5 (15.3), 783 (16.0); MS, m/z: calc. for C35H38N4O5, 594.2657; found, 594.2842.Mendeleev Communications Electronic Version, Issue 6, 2001 2 pared these characteristics with those of purpurin 18.The replacement of the á-hydroxyethyl group with vinyl, and then with acetyl, led to a bathochromic shift of the long-wave band in all these compounds. In the case of bacteriopurpurins, the above shifts were 7, 36 and 43 nm for (4)–(5), (5)–(1) and (4)– (1) pairs, respectively, while in the case of purpurin 18 and its derivatives these values were 4, 27 and 31 nm for analogous pairs.9 Thus, the tetrahydroporphyrin macrocycle is highly sensitive to the introduction of different substituents; this property may be used for the synthesis of new photosensitizers based on bacteriochlorophyll a, which possess intense absorption at 800 nm.This work was supported by the Russian Foundation for Basic Research (grant nos. 01-03-32543 and 00-15-97866). We are grateful to F.V. Toukach (N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences) for the NMR measurements. References 1 R. Bonnett, Chemical Aspects of Photodynamic Therapy. Advanced Chemistry Texts, Gordon and Breach Science Publishers, Amsterdam, 2000, vol. 1. 2 A. N. Kozyrev, G. Zheng, C. Zhu, T. J. Dougherty, K. M. Smith and R. K. Pandey, Tetrahedron Lett., 1996, 37, 6431. 3 A. N. Kozyrev, R. K. Pandey, C. J. Medforth, G. Zheng, T. J. Dougherty and K. M. Smith, Tetrahedron Lett., 1996, 37, 747. 4 A. F. Mironov and V. S. Lebedeva, Tetrahedron Lett., 1998, 39, 905. 5 A. F.Mironov, A. V. Efremov, O. A. Efremova and R. Bonnett, Mendeleev Commun., 1997, 244. 6 A. F.Mironov, A. V. Efremov, O. A. Efremova and R. Bonnett, Tetrahedron Lett., 1997, 38, 6775. 7 A. F. Mironov, A. N. Kozyrev and A. S. Brandis, Proc. Soc. Photo-Opt. Instrum. Eng., 1992, 1922, 204 8 A. F.Mironov, A. V. Efremov, O. A. Efremova, R. Bonnett and G. Martinez, J. Chem. Soc., Perkin Trans. 1, 1998, 3601. 9 A. F. Mironov, Proc. Soc. Photo-Opt. Instrum. Eng., 1995, 2625, 23. Received: 19th September 2001; Com. 01/1845

ISSN:0959-9436     

出版商:RSC    

年代:2001

数据来源: RSC

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 EPR-spectroscopic detection and characterization of a CuII complex with a peroxycarboximidic acid Evgenii P. Talsi,* Galina L. Elizarova, Lyudmila G. Matvienko, Aleksandr A. Shubin and Valentin N. Parmon G. K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation. Fax: +7 3832 34 3766; e-mail: talsi@catalysis.nsk.su 10.1070/MC2001v011n06ABEH001511 A copper(II) complex with peroxycarboximidic acid formed upon the interaction of alkaline hydrogen peroxide with acetonitrile was detected and characterised for the first time.The following reaction of nitriles with alkaline hydrogen peroxide to afford amides (Radzishevski reaction) is well known:1 Since this is a first-order reaction with respect to hydrogen peroxide, Wilberg suggested that the rate-determining step is the formation of peroxycarboximidic acid intermediate X.2 Until now, this intermediate has not been isolated or observed spectroscopically.It is believed that X reacts rapidly with any available reducing agent.3 The oxidising systems based on hydrogen peroxide and nitriles were developed to epoxidise olefins and to oxidise amines (in 60–70% yields).3 Recently, we found that copper and iron hydroxides catalyse the oxidation of organic substrates (including light hydrocarbons) by H2O2 in weakly basic aqueous solutions.4,5 It was assumed that peroxo complexes of Cu and Fe are key intermediates in these oxidations.6,7 The studies on the peroxo complexes of copper in the weakly basic water/acetonitrile solvent systems led us to the discovery of new unstable copper(II) species.Here, we report on the EPR-spectroscopic detection and characterization of this new species identified as a complex of copper(II) with peroxycarboximidic acid intermediate X. For preparation of the sample, Cu(NO3)2 (0.0015 mol) was stirred with a magnetic stirrer at 20 °C in 25 ml of water containing NaOH (0.1 mol) and MeCN (3 mol).Then, hydrogen peroxide (to a concentration of 0.05 mol dm–3) was added. Immediately, the reaction mixture became pale yellow and Cu(OH)2 precipitated. After 3–4 min of stirring, all initially formed Cu(OH)2 dissolved and the solution turned to pale pink. Pink complex 1 was formed.† It exhibits a UV-VIS band at 540 nm and displays an EPR spectrum (15 °C) shown in Figure 1(a).The concentration of 1 monitored by UV-VIS or EPR spectroscopy decreased in parallel with the diminishing of the concentration of hydrogen peroxide in the sample determined by the reaction with TiIV. The half-life time of 1 was about 5 min at 20 °C for the sample of Figure 1. After completion of the reaction, the Cu(OH)2 precipitate forms again.The addition of a fresh portion of hydrogen peroxide to the sample in which all initially added H2O2 was consumed restored the concentration of 1. This procedure can be repeated many times. After completion of the reaction, acetamide was identified as the only product by gas chromatography. According to quantitative EPR measurements, the concentration of 1 can reach 50% of the copper species present in solution.In the absence of acetonitrile, no EPR active species were observed in the reaction of Cu(NO3)2 with alkaline hydrogen peroxide. When benzonitrile was used instead of acetonitrile, a pink EPR active copper(II) complex resembling intermediate 1 was also observed. In the case of benzonitrile, the intermediate formed can be isolated due to its poor solubility as a metastable solid admixture to Cu(OH)2.Its concentration reached 20% of copper in the sample. The IR spectrum of this intermediate (CsI pellet) exhibits a band at 3208 cm–1 assigned to stretching vibrations of the N–H bond, and bands at 896, 871 and 842 cm–1 assigned to O–O vibrations. The latter bands disappeared simultaneously with the decomposition of a pink intermediate. Previously, three bands in the same region were observed by resonance Raman spectroscopy for alkylperoxo complexes LCuOOR, where L is a trispyrazolylborate ligand, and R is tert-butyl or cumyl.These three bands were assigned to mixed O–O/C–O/C–C vibrations in which the O–O percentage determines the isotope shifts and rR intensities.8 Thus, the presented data show that 1 is a mononuclear complex of copper(II) with an unstable product of the reaction of H2O2 with RCN.This unstable product, most probably, contains an O–O bond. The shape of the EPR spectrum of 1 [Figure 1(a)] centered at g0 = 2.12 is typical of mononuclear CuII species. It exhibits four lines due to the hyperfine interaction of an unpaired electron RCN + 2HOOH ® RC(O)NH2 + O2 + H2O (1) RCN + 2HOOH® HN=C(OOH)R + HOOH ® RC(O)NH2 +O2 + H2O (2) X HN=C(OOH)R + S ® RC(O)NH2 + SO (3) a0, Cu g = 2.0023 (b) (a) 3000 3100 3200 3300 3400 B/G Figure 1 X-band (9.3 GHz) EPR spectra recorded 5 min after the addition of hydrogen peroxide to a solution of Cu(NO3)2 in (a) H2O–MeCN–NaOH (15 °C) and (b) H2O–CD3CN–NaOH (25 °C).[Cu(NO3)2] = 0.0015 mol dm–3, [H2O2] = 0.05 mol dm–3, [NaOH] = 0.1 mol dm–3, [CD3CN] = [MeCN] = 3 mol dm–3. † General experimental details. Reagent grade Cu(NO3)2, MeCN and 30% H2O2 were used without further purification. Commercial CD3CN from Aldrich was used. The EPR spectra (20 °C) were recorded in a flat quartz cell furnished with a Bruker ER-200D X-band spectrometer.The EPR spectra (–196 °C) were recorded in glass tubes (5 mm in diameter) in a quartz finger dewar vessel. The concentrations of paramagnetic centres were measured by comparing the second integrals of EPR spectra of the test sample and the reference crystal of CuCl2·2H2O at –196 °C. The EPR spectra were simulated using the EPR1 program.16 The UV-VIS spectra were recorded on a Uvikon 923 spectrometer, and the IR spectra were measured on a FTIR BOMEM MB-102 instrument.O O Cu N O O N H H cis O N Cu O O O N H trans H Figure 2 Structure of complex 1.Mendeleev Communications Electronic Version, Issue 6, 2001 2 with a copper nucleus (I = 3/2, a0 = 86 G). Besides, the upfield component of the spectrum displays an additional hyperfine structure (ahfs). The observed splitting (a = 11 G) is typical of ahfs from nitrogen nuclei.However, the splitting pattern observed (approximately 1:3:6:6:3:1) is far from that expected for ahfs from two nitrogen nuclei (1:2:3:2:1). The splitting pattern 1:3:5:5:3:1 resembling the experimental one can be obtained on the assumption of the existence of equal amounts of two types of complexes with 1:2:3:2:1 splitting patterns (a = 11 G) and slightly different g0 values (the shift between two spectra of about 10 G).To exclude the impact of ahfs from hydrogen nuclei to the observed spectrum, CD3CN, D2O and NaOD were used for preparation sample instead of ordinary reagents (hfs from deuterium is lower than that from proton by a factor of 6). EPR spectra coincided for deuterated and ordinary reagents at the same temperature. Thus, the observed ahfs is due to only nitrogen nuclei.Note that the shape of the EPR spectrum of 1 is very temperature sensitive. Figure 1(b) shows the EPR spectrum of 1 obtained in the CD3CN/H2O/H2O2 system at 25 °C. It can be seen that the ahfs structure almost disappeared in this spectrum. The EPR spectrum of this sample recorded at 12 °C coincided with the spectrum shown in Figure 1(a).An additional hyperfine structure observed in Figure 1(a) can be described as a superposition of spectra from two copper complexes each of them containing two nitrogen atoms in a coordination sphere. Thus, most probably, 1 incorporates two peroxycarboximidic acid ligands and exists in solution in the form of two isomers, e.g., cis–trans isomers (Figure 2).Such isomers are known for related bis(N-R)salicylaldiminatocopper(II) complexes. 9 The EPR spectrum (20 °C) of bis(N-methyl)salicylaldiminatocopper( II) is a superposition of the spectra of two isomers.10 The EPR spectrum of a frozen solution of 1 (–196 °C, Figure 3) is well described by a theoretical spectrum (dotted line) with the following parameters: g1 = 2.221, A1 = 226 G, g2 = 2.061, A2 = = 22.1 G, g3 = 2.0584, A3 = 19.4 G.These parameters are typical of plane mononuclear copper(II) species with O and N donor ligands. An additional hyperfine structure from the NH=C(Me) fragment is unresolved in the EPR spectrum shown in Figure 3. During the last decade, much effort has been devoted to the design and synthesis of inorganic models of the catalytic sites of noncoupled binuclear copper enzymes, where a peroxide intermediate may be activated by coordination to only one copper ion.8,11–15 Some mononuclear alkylperoxo and hydroperoxo copper(II) complexes were structurally and spectroscopically characterised.11–15 Complex 1 can be considered as an intermediate of the interaction of a hydroperoxo complex of copper(II) with an organic substrate (acetonitrile in our case). Evidently, a study of this species is important for the elucidation of the mechanisms of catalytic oxidation.The advantage of the test system is its simplicity. The reaction proceeds in water as a solvent, and the catalyst used incorporates only water molecules and OH groups in its composition. In conclusion, we observed for the first time a complex of copper(II) with peroxycarboximidic acid formed in the reaction of alkaline hydrogen peroxide with acetonitrile by EPR spectroscopy.This work was supported by the Russian Foundation for Basic Research (grant no. 00-03-32438) and the Programme of Leading Scientific Schools (grant no. 00-15-97446). References 1 E.N.Zilberman, Reaktsii nitrilov (Reactions of Nitriles), Khimiya, Moscow, 1972 (in Russian). 2 K.B.Wiberg, J. Am. Chem. Soc., 1953, 75, 3961. 3 G. B. Payne, P. H. Deming and P. H. Williams, J. Org. Chem., 1961, 26, 659. 4 A. O. Kuzmin, G. L. Elizarova, L. G. Matvienko, E. N. Savinova and V. N. Parmon, Mendeleev Commun., 1998, 210. 5 G. L. Ellizarova, L. G. Matvienko, A. O. Kuzmin, E. R. Savinova and V. N. Parmon, Mendeleev Commun., 2001, 15. 6 G. L. Elizarova, L. G. Matvienko, O. L. Ogorodnikova and V. N. Parmon, Kinet. Katal., 2000, 41, 366 [Kinet. Catal. (Engl. Transl.), 2000, 41, 332]. 7 G. L. Elizarova, L. G. Matvienko and V. N. Parmon, Kinet. Katal., 2000, 41, 839 [Kinet. Catal. (Engl. Transl.), 2000, 41, 760]. 8 P. Chen, K. Fujisawa and E. Solomon, J. Am. Chem. Soc., 2000, 122, 10177. 9 S.Yamada and A. Takeuchi, Coord. Chem. Rev., 1982, 43, 187. 10 V. F. Anufrienko, E. G. Rukhadze, G. V. Panova and A. G. Onuchina, Dokl. Akad. Nauk SSSR, 1966, 171, 601 [Dokl. Chem. (Engl. Transl.), 1966, 171, 1088]. 11 F. Champloy, N. Benali-Cherif, P. Bruno, I. Blain, M. Pierrot, M. Reglier and A. Michalowicz, Inorg. Chem., 1998, 37, 3910. 12 A. Wada, M. Harata, K. Hasegawa, K. Jitsukawa, H. Masuda, M. Mukai, T. Kitagawa and H. Einaga, Angew. Chem., Int. Ed. Engl., 1998, 37, 798. 13 I. Sanyal, P. Ghosh and K. D. Karlin, Inorg. Chem., 1995, 34, 3050. 14 N. Kitajima, T. Katayama, K. Fujisawa, Y. Iwata and Y. Moro-oka, J. Am. Chem. Soc., 1993, 115, 7872. 15 N. Kitajima, K. Fujisawa and Y. Moro-oka, Inorg. Chem., 1990, 29, 357. 16 A. A. Shubin and G. M. Zhidomirov, Zh. Strukt. Khim., 1989, 30, 67 [J. Struct. Chem. (Engl. Transl.), 1989, 30, 414]. 2800 3000 3200 3400 B/G g = 2.0023 Figure 3 X-band (9.3 GHz) EPR spectrum (–196 °C) recorded 5 min after the addition of hydrogen peroxide to a solution of Cu(NO3)2 in H2O–MeCN– NaOH. [Cu(NO3)2] = 0.0015 mol dm–3, [H2O2] = 0.05 mol dm–3, [NaOH] = = 0.1mol dm–3, [CD3CN] = [MeCN] = 3 mol dm–3. Dotted line shows a theoretical spectrum with the parameters specified in the text. Received: 8th August 2001; Com. 01/1837

ISSN:0959-9436     

出版商:RSC    

年代:2001

数据来源: RSC

摘要:

Mendeleev Communications Electronic Version, Issue 6, 2001 1 Polyfunctionalised surfactant-templated adsorbents with high specific surface areas Yurii L. Zub,*a Inna V. Seredyuk,a Alexei A. Chuiko,a Mietek Jaroniec,b Merfyn O. Jones,c Richard V. Parishc and Stephen Mann*d a Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 03164 Kiev, Ukraine. E-mail: zub@ukma.kiev.ua b Department of Chemistry, Kent State University, Kent, Ohio 44242, USA c Department of Chemistry, UMIST, PO Box 88, Manchester M60 1QD, UK d School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.E-mail: S.Mann@bristol.ac.uk 10.1070/MC2001v011n06ABEH001486 The single-step synthesis and structure–adsorption characteristics of trifunctionalised surfactant-templated adsorbents are described.Designing adsorption selectivity is of importance in the development of materials for advanced catalytic, environmental and nanotechnological applications. It is possible to distinguish between structural (geometrical) selectivity arising from the presence of pores of certain shape and size and chemical selectivity arising from the presence of functional groups on the surface of the adsorbent.Thus, modern adsorption applications require materials with both tailored structural and surface properties. A simple and effective method for the synthesis of such adsorbents in one step involves the use of two or more functional components and a suitably matched templating agent. For example, functional trialkoxysilanes (RO)3SiR' can be used as a source of desired functional groups R', tetraalkoxysilanes Si(OR)4, as a framework-building agent, and surfactant micelles, as a mesostructure- directing template.This template-directed co-condensation approach is very promising because of the availability of various (RO)3SiR' organosilanes and self-assembled organic aggregates.1 It was found previously that two-component mixtures of alkoxysilanes can be used for preparing surfactant-templated mesoporous adsorbents with high surface areas and functional groups such as aryl,2 amine,3,4 thiol4–6 and sulfate groups.7,8 To the best of our knowledge there is only one report describing a bifunctionalised MCM-type silica prepared from a mixture of tetraethoxysilane (TEOS) and two different organo-functionalised silanes.9 Here, we report the one-stage synthesis and structure– adsorption characteristics of surfactant-templated adsorbents prepared using four-component mixtures of organosilanes. This approach allows us to tailor not only the porous structure of the resulting adsorbents but also their surface functionality by introducing up to three types of covalently linked organic groups.Trifunctionalised organosilica–surfactant mesophases were synthesised at room temperature and ambient pressure using mixtures of varying molar ratios of TEOS and functional organotrialkoxysilanes (FOS) in the presence of the neutral surfactant n-dodecylamine (DDA).Various combinations were studied (Table 1). The molar composition of a typical reaction mixture was 0.1 TEOS : 0.02 (total) FOS : 0.03 DDA : (2.2–2.8) H2O.† The following FOS were used: 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropyltrimethoxysilane (MPTMS), N-[3-(trimethoxysilyl) propyl]ethylenediamine (TMPED), bis[3-(trimethoxysilyl) propyl]amine (BTMPA), methyltrimethoxysilane (MTMS) and phenyltriethoxysilane (PTES).In each case, the surfactant was removed by solvent extraction to produce polyfunctionalised porous silicas.Low-angle powder X-ray diffraction (XRD) data‡ indicated that a single phase was formed in materials containing up to 20 mol% FOS in the initial synthesis mixture. In each case, a single peak was observed, indicative wormlike mesostructures10 (Figure 1). Except for materials prepared from mixtures of TEOS/APTES/MPTMS or TEOS/TMPED/MPTMS, the functionalised mesostructures remained intact after surfactant extraction, although small lattice contractions were sometimes observed (Table 1).The XRD data were confirmed by transmission electron microscopy (TEM) images,‡ which showed no evidence for a long-range ordered mesostructure after surfactant removal. Scanning electron microscopy studies of the polyfunctionalised adsorbents indicated that spherical particles were formed in each sample.‡ Intensity (a.u.) III V VIII IX 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 2q/° Figure 1 Powder XRD patterns for samples III, V, VIII and IX (see Table 1) after removal of the DDA template.† Typical conditions: continuous stirring, 22.30 cm3 (0.1 mol) of TEOS, 1.56 cm3 (0.0067 mol) of APTES, 1.26 cm3 (0.0067 mol) of MPTMS, and 0.95 cm3 (0.0067 mol) of MTMS were added to 5.56 g (0.03 mol) of DDA in 60 cm3 of absolute EtOH.Then, without termination of stirring, 40 to 50 cm3 of water was added drop-by-drop for 2 min (up to the appearance of turbidity). After 1 min, a substantial amount of a white precipitate was formed. The precipitate was allowed to stand for 24 h at room temperature, then filtered off, quickly washed with 50 ml of EtOH and dried in air for 24–48 h.Extraction of the template was carried out in boiling MeOH for 3 h (3×300 ml of MeOH per 10 g sample). The white precipitate was dried in vacuo for 4 h. ‡ X-Ray diffraction powder patterns were collected on a Scintag XDS2000 diffractometer using Copper radiation having a wavelength of 1.54060 Å. TEM images were recorded on a JEOL JEM-2000 FXII electron microscope operated at 300 kV.Samples were dispersed ultrasonically in EtOH, and a drop of the suspension was air-dried onto a carbon-coated grid. Scanning electron micrographs (SEM) were obtained with a JEOL Superprobe 733 microscope. Infrared spectra were recorded on a Nicolet 5 PC FT spectrophotometer using samples pressed with KBr.High-resolution solid-state 13C CPMAS and 29Si DPMAS NMR measurements were carried out on a Varian UNITYplus spectrometer and 7 mm (rotor o.d.) Doty Scientific MAS probe (with respect to an external reference sample of tetramethylsilane). Thermal analysis was performed in the range 20– 800 °C with a heating rate of 5 °C min–1 (in an air stream; E. Paulik, J. Paulik, L. Erdey System, Q-1500 D).Mendeleev Communications Electronic Version, Issue 6, 2001 2 Nitrogen adsorption studies (Table 1) confirmed that the surfactant- extracted materials possessed pores ranged in size between micro- and mesoporosity.The pore size at the distribution maximum, calculated using the KJS method,11 were between 1.8 and 3 nm. In general, a decrease in the pore size was observed when PTES was used as one of the components, whereas higher specific surface areas were obtained in the presence of BTMPA.The presence of arched structures consisting of [O3Si(CH2)3–NH–(CH2)3SiO3] linkages on the pore surface could be responsible for the larger pore diameters. The IR spectra‡ exhibited a strong absorption band in the range between 1060 and 1195 cm–1 characteristic of functionalised polysiloxanes. The band was split into two components (or a shoulder), consistent with the formation of a three-dimensional skeleton.12 The IR spectra also showed bands characteristic of R' functional groups.The samples heated to 150 °C in vacuo exhibited three or sometimes four resolved weak ns,as (CH) bands indicating the presence of thermally stable methoxy (ºSi–OMe) groups on the surface,13 which are formed during the methanol extraction of the template.This is supported by the following observations: first, an excess in the carbon content (Table 1); second, the IR spectrum of the silica sample obtained from TEOS in the presence of DDA using the same experimental procedure exhibited three bands at 2856, 2930 and 2965 cm–1, which remained after heating the sample in vacuo at 200 °C, whereas the IR spectrum of this sample calcined at 540 °C in order to remove DDA does not show these bands; third, the 13C CPMAS NMR spectrum of the extracted sample showed a signal at 49.0 ppm, which is typical of MeOSiº, and this signal was present after heating the sample in vacuo to 105 °C. The incorporation of covalently linked organic groups was also confirmed by 29Si DPMAS NMR spectroscopy,‡ which revealed well-defined resonances for siloxane [Qn = Si(OSi)n(OH)4–n, n = = 2–4] and organosiloxane [Tm = R'Si(OSi)m(OH)3–m, m = 2–3] environments.For instance, in the case of sample IX, which contains aminopropyl, mercaptopropyl and phenyl moieties, the 29Si DPMAS spectrum showed two major sets of resonances from –90 to –110 and at ca.–70 ppm, respectively [Figure 2(a)]. The first region contains two intense peaks at –110.2 and –101.4 ppm and one very weak peak at –92.7 ppm, which were assigned to Q4, Q3 and Q2, respectively. The distinct peak at –66.5 ppm was assigned to T3(propyl), the shoulder at –58.8 ppm to T2(propyl), and the weak peak at –77.0 ppm and the shoulder at –80.7 ppm, to the T2 and T3 units, respectively, containing covalently linked phenyl groups.The trifunctional nature of the materials was also corroborated by 13C CP MAS NMR studies. For sample IX, for example, signals attributed to propyl chains linked to silicon atoms (d is 10.4, 20.4, 27.4 and 49.7 ppm) and phenyl carbons (127–134 ppm) were observed [Figure 2(b)]. The thermal analysis‡ of samples III, VIII and IX indicated the loss of residual solvent with maxima at 80, 100 and 130 °C, respectively.This was followed by minor mass losses (ca. 4.2, 2.8 and 3.5%) centered at 340, 350 and 320 °C, and major losses (ca. 13.6, 12.5 and 16.5%) centered at 583, 572 and 590 °C, respectively. These data indicate that the polyfunctionalised materials were stable with covalently bonded organic groups.The above results indicate that the surfactant-directed cocondensation of TEOS and organosilanes can be extended to a combination of three organic functionalities that are covalently linked to the porous silica framework. Such materials should be useful in a wide range of applications such as the adsorption of toxic metal ions1 and catalysis.14 It should be possible to extend the synthesis strategy to polyfunctionalised silica-based adsorbents in the form of thin films and monoliths.The preparation of hybrid nanoporous and mesoporous siliceous materials with controlled multi-functionality, porosity and hydrophobicity could also open up new avenues for research in metalloorganic, organic and inorganic host–guest chemistry.Yu. L. Z. thanks The Royal Society for a partial financial support of this work. The NSF grant CTS-0086512 (M.J.) is gratefully acknowledged. We thank Dr. D. C. Apperley (University of Durham) for the solid state NMR data and Dr. H. Honda (Tsukuba Research Laboratory, Sumitomo Chemical Co., Ltd) for TEM figures. References 1 J. Brown, L. Mercier and T. J. Pinnavaia, Chem.Commun., 1999, 69. 2 S. L. Burkett, S. D. Sims and S. Mann, Chem. Commun., 1996, 1367. 3 D. J. MacQuarrie, Chem. Commun., 1996, 1961. 4 C. E. Fowler, S. L. Burkett and S. Mann, Chem. Commun., 1997, 1769. 5 R. Richer and L. Mercier, Chem. Commun., 1998, 1775. 6 Y. Guo and A. R. Guadalupe, Chem. Commun., 1999, 315. 7 W. M. Van Rhijn, D. E. De Vos, B. F. Sels, W. D. Bossaert and P.A. Jacobs, Chem. Commun., 1998, 317. 8 M. H. Lim, C. T. Blanford and A. Stein, Chem. Mater., 1998, 10, 467. Table 1 Characterization of the polyfunctionalised surfactant-templated materials. Composition XRD d spacing/Å (AS/SE)a aAS = as synthesised, SE = surfactant extracted. bRelative pressures from 0.05 to 0.20 were used. cCalculated at the maximum of pore size distribution using the KJS method.11 dCarbons of amino and mercaptopropyl groups (calculated from %N and %S) are not included.Nitrogen adsorption Amino content/ mmol g–1 SH content/ mmol g–1 Carbond content/ mmol g–1 BET surface areab/m2 g–1 Vs/cm3 g–1 Pore size,c d/nm I. TEOS/APTES/MPTMS 32.4/— 74 0.04 1.7 1.16 0.97 1.53 II. TEOS/TMPED/MPTMS 30.8/— 76 0.14 2.8 2.20 0.97 2.17 III. TEOS/BTMPA/MPTMS 37.5/37.4 725 0.48 3.0 0.79 0.44 3.45 IV. TEOS/APTES/MPTMS/MTMS 31.9/31.2 490 0.24 2.1 0.80 0.70 2.45 V.TEOS/APTES/MPTMS/PTES 31.6/31.6 490 0.24 1.8 0.65 0.67 5.87 VI. TEOS/TMPED/MPTMS/MTMS 33.2/32.2 450 0.32 2.1 1.46 0.71 2.66 VII. TEOS/TMPED/MPTMS/PTES 30.0/29.6 390 0.19 1.8 1.55 0.70 7.05 VIII. TEOS/BTMPA/MPTMS/MTMS 32.4/31.9 825 0.37 2.3 0.65 0.54 3.99 IX. TEOS/BTMPA/MPTMS/PTES 31.7/31.9 720 0.34 2.2 0.58 0.57 6.71 Figure 2 (a) 29Si DPMAS NMR spectrum and (b) 13C CPMAS NMR spectrum of sample IX after surfactant extraction. 220 180 140 100 60 20 –20 d/ppm –20 –60 –100 –140 –180 d/ppm (a) (b)Mendeleev Communications Electronic Version, Issue 6, 2001 3 9 S. R. Hall, C. E. Fowler, B. Lebeau and S.Mann, Chem. Commun., 1999, 201. 10 S. A. Bagshaw, E. Prouzet and T. J. Pinnavaia, Science, 1995, 269, 1242. 11 M. Kruk, M. Jaroniec and A. Sayari, Langmuir, 1997, 13, 6267. 12 L. P. Finn and I. B. Slinyakova, Kolloidn. Zh., 1975, 37, 723 [Colloid J. USSR (Engl. Transl.), 1975, 37, 651]. 13 Wei Li and R. J. Willey, J. Non-Cryst. Solids, 1997, 212, 243. 14 D. J. MacQuarrie and D. B. Jackson, Chem. Commun., 1997, 1781. Received: 18th June 2001; Com. 01/1812

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 Ice-like (H2O)12 and (H2O)14 clusters in the crystal structures of alkali metal.ethyl viologen hexacyanometallates Mikhail Yu. Antipin,a Andrei B. Ilyukhinb and Vitalii Yu. Kotov*b a A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow, Russian Federation. Fax: +7 095 135 5085 b N. S.Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation. Fax: +7 095 954 1279; e-mail: ilyukhin@igic.ras.ru 10.1070/MC2001v011n06ABEH001503 The (H2O)12 and (H2O)14 water clusters found in the crystal structures of alkali metal.ethyl viologen hexacyanometallates are similar to analogous structural units in ice Ih and ice XI. The structures of gas hydrates with three-dimensional frameworks of water molecules the tunnels or polyhedral cavities of which contain solute molecules (clathrates)1,2 were adequately characterised.Hydrates with water molecules arranged in channels or cavities within a rigid framework, such as an aluminosilicate framework of zeolites, are also well known. The most widespread crystal hydrates in which cations and anions are packed together with water molecules occupy an intermediate position between the above limiting structures.1 In this case, compact water clusters may be formed.For example, clusters containing eight3 and ten4 water molecules were detected. In this work, the crystal structure of the lithium ethyl viologen hexacyanoferrate EV1.5Li[Fe(CN)6]¡�14H2O¢Ó 1 (EV2+ is N,N'-diethyl- 4,4'-bipyridinium) containing a cluster of 14 water molecules was studied.The results were compared with previous data5 on isostructural compounds EV1.5K[M(CN)6]¡�12.5H2O 2 (M = Fe or Ru), in which (H2O)12 structural units were detected (Figures 1 and 2). We found that O(3) and O(4) water molecules in 2 (Figure 2) occupy spherical cavities 11 A in diameter formed by ethyl viologen cations and form ice-like (H2O)12 clusters.The replacement of potassium with lithium dramatically increased parameter c [20.853, 20.956 and 21.586 A for 2 (Fe), 2 (Ru) and 1, respectively]. This is due to the fact that the alkali metal coordination changed from octahedral to tetrahedral and this change was accompanied by the incorporation of an additional water molecule [O(6)] into the chain A(H2O)x[M(CN)6] (A = K, x = 3; A = Li, x = 4) (Figure 1).An increase in parameter c is a reflection of the ordering of water molecules O(5). Thus, the formula unit of 1 contains 1.5 additional water molecules as compared with that of 2; however, the main structural motif remained unchanged. The ordering of water molecules O(5) makes it possible to recognise a (H2O)14 cluster in 1.The (H2O)12 and (H2O)14 clusters form (H2O)18 and (H2O)20 units in the structures of 2 and 1, respectively, via six hydrogen bonds with crystal water molecules O(2). Taking into account water molecules O(1) coordinated to alkali metal atoms, the dimensionality of the units increases to (H2O)24 and (H2O)26, respectively.The geometry parameters of the (H2O)18 unit are similar to those of ice Ih 6 and ice XI.7 Two types of six-membered rings can be recognised in this unit: three O(3).O(4). O(3E).O(3C).O(4C).O(3B) with boat conformations and two O(3).O(4).O(3E).O(4E).O(3D).O(4D) with chair conformations. The orientation of hydrogen bonds in the structure of ice Ih is disordered, whereas these bonds in the structure of ice XI are oriented along oxygen.oxygen bonds.We localised all hydrogen atoms in the test (H2O)12 clusters from difference Fourier syntheses. However, the number of short O¡�¡�¡�O contacts is greater than the number of hydrogen atoms that participate in the formation of hydrogen bonds, and hydrogen atoms are located at not all O¡�¡�¡�O lines (Figure 2). Note that in the structure of 2 (Fe) hydrogen atoms of molecule O(4) form hydrogen bonds O(4)¡�¡�¡� O(3), O(4)¡�¡�¡�O(51, 52), and in 2 (Ru) and 1, O(4)¡�¡�¡�O(3) and ¢Ó The compound EV1.5Li[Fe(CN)6]¡�14H2O 1 was isolated by the mixing (T = 277 K) of solutions of ethyl viologen diiodide (Aldrich) and lithium hexacyanoferrate (pure) in the 1:1 molar ratio.Crystal structure data for 1: C27H55FeLiN9O14, M 792.59, trigonal, space group P3c1 (no. 165), a = 14.6690(10) A, c = 21.586(5) A, V = = 4022.6(10) A3, Z = 4, dcalc = 1.309 g cm.3, F(000) = 1684. Crystal size 0.4¡¿0.3¡¿0.3 mm. Experiments were performed on a Smart 1000 CCD diffractometer using MoK¥á-radiation (l = 0.71073 A, w-scans with a 0.3¡Æ step and 10 s per frame exposure, 2q < 60¡Æ) at 110 K. The intensities of 24136 reflections were measured within the range 1.89 < q < 30.05¡Æ; 3884 independent reflections were used in the calculations (Rint = 0.0622).The model of 2 (without oxygen atoms of the crystal water and without a potassium atom) was used as an initial approximation in refining. The structure was refined by the least-squares technique in an anisotropic. isotropic approximation (H atoms).The final refinement parameters: wR2 = 0.1764, R1 = 0.1037 (all reflections), wR2 = 0.1598, R1 = 0.0683 [2229 reflections with I > 2s(I)], GOF = 0.923 (225 refinement parameters). All calculations were performed using the SHELXL 97 program.8 Atomic coordinates, bond lengths, bond angles and thermal parameters have been deposited at the Cambridge Crystallographic Data Centre (CCDC).For details, see ¡®Notice to Authors¡�, Mendeleev Commun., Issue 1, 2001. Any request to the CCDC for data should quote the full literature citation and the reference number 1135/100. 1 2 C(2A) C(2B) C(2) N(2) N(1) C(1) Fe(1) C(1A) C(1B) O(6) O(1B) O(1A) Li(1) O(1) Fe(1A) Li(1A) C(1B) C(1A) Ru(1) C(2) C(1) N(1) N(2) C(2B) C(2A) K(1) O(1B) O(1) O(1A) Ru(1A) K(1A) Figure 1 Chains of the A(H2O)x[M(CN)6] ion pairs in the structures of 1 and 2 (Ru). Figure 2 Structural units of 1 and 2 (Ru).The geometry of O¡�¡�¡�O¡�¡�¡�O contacts (¡Æ and A) in 1: O(3)¡�¡�¡�O(2C) 2.881, O(3)¡�¡�¡�O(3B) 2.777, O(3)¡�¡�¡�O(4) 2.826, O(3)¡�¡�¡�O(4D) 2.871, O(4)¡�¡�¡�O(5) 2.755, O(2C).O(3).O(3B) 105.4, O(2C).O(3).O(4) 118.0, O(2C).O(3).O(4D) 122.3, O(3B).O(3).O(4) 121.0, O(3B).O(3).O(4D) 103.5, O(4).O(3).O(4D) 85.9, O(3).O(4).O(3E) 122.0, O(3).O(4).O(5) 90.4, O(3E).O(4).O(5) 89.5, O(4).O(5).O(4E) 89.6. 1 2 O(2) O(2D) O(3D) O(4D) O(4E) O(5) O(2C) O(3) O(4) O(3E) O(2A) O(4B) O(3A) O(3B) O(2B) O(4A) O(5A) O(4C) O(3C) O(2E) O(2) O(2D) O(52) O(51) O(4E) O(2C) O(3) O(4D) O(3D) O(4) O(2A) O(2E) O(3C) O(3E) O(4C) O(51A) O(52A) O(4A) O(2B) O(3B) O(4B) O(3A)Mendeleev Communications Electronic Version, Issue 6, 2001 2 O(4)···O(3E), respectively. This fact suggests partial disordering of the hydrogen atoms of water molecules in compounds 1 and 2.Unfortunately, disordered hydrogen atoms cannot be reliably localised even at 110 K because of the mosaic structure of crystals. References 1 A. F. Wells, Structural Inorganic Chemistry, Clarendon Press, Oxford, 1986. 2 Yu. A. Dyadin, I. S. Terekhova, T. V. Rodionova and D. V. Soldatov, Zh. Strukt. Khim., 1999, 40, 797 [J. Struct. Chem. (Engl. Transl.), 1999, 40, 645]. 3 (a) W. B. Blanton, S. W. Gordon-Wylie, G. R. Clark, K. D. Jordan, J. T. Wood, U. Geiser and T. J. Collins, J. Am. Chem. Soc., 1999, 121, 3551; (b) J. L. Atwood, L. J. Barbour, T. J. Ness, C. L. Raston and P. L. Raston, J. Am. Chem. Soc., 2001, 123, 7192. 4 (a) L. J. Barbour, G. W. Orr and J. L. Atwood, Nature, 1998, 393, 671; (b) L. J. Barbour, G. W. Orr and J. L. Atwood, Chem. Commun., 2000, 859. 5 S. A. Kostina, A. B. Ilyukhin, B. V. Lokshin and V. Yu. Kotov, Mendeleev Commun., 2001, 12. 6 A. Goto, T. Hondoh and S. Mae, J. Chem. Phys., 1990, 93, 1412. 7 R. Howe and R. W. Whitworth, J. Chem. Phys., 1989, 90, 4451. 8 G.Mity of Göttingen, Germany. Received: 18th July 2001; Com. 01/1829

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 Structure of zirconium complexes in aqueous solutions Vladislav V. Kanazhevskii,a Boris N. Novgorodov,b Vera P. Shmachkova,*b Nina S. Kotsarenko,b Vladimir V. Kriventsovb and Dmitrii I. Kochubeyb a Department of Physics, Novosibirsk State University, 630090 Novosibirsk, Russian Federation b G. K. Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russian Federation.Fax: +7 3832 34 3056; e-mail: vera@catalysis.nsk.su 10.1070/MC2001v011n06ABEH001509 Two types of zirconium(IV) complexes with the different Zr.Zr distances were detected by EXAFS in the aqueous solutions of ZrOCl2¡�8H2O, ZrO(NO3)2¡�2H2O and Zr(SO4)2¡�4H2O salts. Zirconium oxides are traditionally prepared starting from the solutions of zirconium salts, which contain various polynuclear complexes.The composition and properties of the precipitate can be controlled by varying the composition of solutions.1,2 Zirconium oxychloride solutions were studied using various spectroscopic techniques.3.9 It was found that, in such solutions, zirconium occurs as complexes structurally similar to the base unit of crystalline zirconium oxychloride.10.13 The complex exhibits the structure of a slightly distorted square with zirconium atoms arranged at its corners (Zr.Zr1 is 3.6 A; Zr.Zr2 is 5.1 A) and with the distances Zr.OH of 2.14, 2.22 and 2.35 A and Zr.OH2 of 2.09, 2.13 and 2.37 A.The tetrameric complexes form larger polynuclear complexes in the course of ageing.7,11 Unfortunately, the structure of both tetrameric and polynuclear complexes is still not clearly understood.However, it was well established that eight oxygen atoms are coordinated to a zirconium atom, and the interatomic distances range from 2.1 to 2.24 A. We believe that the solutions of ZrOCl2¡�8H2O, ZrO(NO3)2¡�2H2O and Zr(SO4)2¡�4H2O also contain polynuclear complexes.In this work, we studied aqueous solutions of zirconium salts by EXAFS. The 0.5 M solutions were prepared using chemically pure ZrOCl2¡�8H2O and ZrO(NO3)2¡�2H2O salts and Zr(SO4)2¡�4H2O crystallised from a concentrated sulfuric acid solution according to the published procedure.14 In addition, we also studied zirconium oxychloride solutions aged at room temperature for 12 months.The X-ray absorption spectra at the zirconium K-edge were measured according to the standard method15 at the EXAFS Station of the Siberian Synchrotron Radiation Centre (Novosibirsk). For this purpose, the sample thickness was chosen to obtain .¥ìx = 0.8 for zirconium. For all samples, the oscillating parts of absorption spectra [c(k)] were analysed as k3c(k) in the wavenumber range k = = 3.16 A.1.The VIPER16 and EXCURV9217 programs were used for data processing. Figure 1 shows the radial distribution functions obtained from the EXAFS spectra of the initial solutions by Fourier transform. Table 1 summarises the calculated structural data. In all samples, the measured average Zr.O distance is close to 2.2 A, a typical average distance for the oxygen environment of zirconium.We observed two pairs of Zr.Zr distances: 3.6 and 5.1 A and 3.3 and 4.7 A. Upon ageing of the chloride solution, the intensity ratio at the distances 3.3 and 3.6 A changed from 1:3 to 1:1. Because interatomic distances in all complexes are similar, it is believed that their structure is similar to that of the zirconium oxychloride solution; that is, all complexes are tetramers with the structure described above.The presence of two sets of Zr.Zr distances (3.3 and 4.7 A and 3.6 and 5.1 A) and the change in the peak intensity ratio with changing the anion or ageing the solution suggest the presence of two different zirconium tetramers with the above Zr.Zr distances. For both complexes, a Zr.Zr distance is greater than the other distance by about 21/2; this fact suggests that the above complexes exhibit a squareplanar configuration.The Zr.Zr distances equal to 3.6 and 5.1 A are typical of zirconium hydroxide, cubic zirconium oxide and the majority of basic zirconium(IV) salts, including solid zirconium oxychloride. Previously,7 it was found by SAXS that complexes may contain different numbers of chloride ions in their structure and hence exhibit different ionic charges. A change in the ionic charge can be responsible for a change in the Zr.Zr distance. We believe that the occurrence of two pairs of interatomic distances in the test solutions of zirconium sulfate, oxychloride and oxynitrate is also associated with the different numbers of anions coordinated to the square-planar framework of zirconium cations.It is likely that the Zr.Zr distance changes on varying the charge of the complex ion, which is determined by the number of coordinated anions and weakly depends on the nature of anions. This distance is equal to 3.38 A in ZrO(NO3)2¡�2H2O or ZrOCl2¡�8H2O, whereas it is 3.25 A in the case of Zr(SO4)2¡�4H2O. The reason for this difference will be studied later on.Table 1 Structure of the local environment of zirconium according to EXAFS. Sample Distance/A Coordination number Debye.Waller factor/A2 ZrO(NO3)2 Zr.O Zr.Zr 2.189 3.377 3.627 4.590 5.176 4.1 0.3 0.3 1.4 0.9 0.009 0.002 0.005 0.028 0.018 ZrOCl2 Zr.O Zr.Zr 2.172 3.373 3.649 4.769 5.220 6.1 0.2 0.6 0.4 1.0 0.011 0.002 0.006 0.022 0.017 ZrOCl2 a aThe solution was aged for 12 months at room temperature.Zr.O Zr.Zr 2.151 3.325 3.568 4.710 5.108 5.9 1.4 1.7 1.2 0.9 0.007 0.010 0.013 0.019 0.011 Zr(SO4)2 Zr.O Zr.Zr 2.222 3.251 3.607 4.653 5.112 5.3 1.1 1.6 0.5 0.7 0.015 0.016 0.012 0.010 0.011 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0 1 2 3 4 5 6 7 8 9 10 Intensity (a.u.) R/A 0.10 0.05 0.00 .0.05 .0.10 .0.15 k/A k3c(k) 4 5 6 7 8 9 10 11 12 13 14 15 Zr.O Zr.Zr1 Zr.Zr2 1 2 3 1 2 3 Figure 1 Radial distribution functions obtained from the EXAFS spectra of the solutions of (1) zirconium oxynitrate, (2) zirconium oxychloride and (3) zirconium sulfate.Inset: the oscillating part of the absorption coefficient c(k) for k = 3.16 A.1.Mendeleev Communications Electronic Version, Issue 6, 2001 2 Thus, the complexes formed in the aqueous solutions of zirconium oxychloride, zirconium oxynitrate and zirconium sulfate are structurally similar. They exhibit a square-planar configuration of zirconium ions.Two types of zirconium complexes different in the Zr–Zr distance were detected in aqueous solutions. We believe that the difference in complex structures is associated with different numbers of anions entering the complex and, consequently, with the difference in the charge of the complex.This work was supported by CRDF (grant no. REG 008) and INTAS (grant no. 00-00863). References 1 O. P. Krivoruchko, R. A. Buyanov and M. A. Fedotov, Zh. Neorg. Khim., 1978, 23, 1798 (Russ. J. Inorg. Chem., 1978, 23, 988). 2 M. A. Fedotov, O. P. Krivoruchko and R. A. Buyanov, Zh. Neorg. Khim., 1978, 23, 2326 (Russ.J. Inorg. Chem., 1978, 23, 1282). 3 S. Hannane, F. Bertin and J. Bouix, Bull. Soc. Chim. Fr., 1990, 127, 43. 4 G. M. Muha and P. A. Vaughan, J. Chem. Phys., 1960, 33, 194. 5 M.Aberg, Acta Chem. Scand., 1977, B31, 171. 6 L. M. Toth, J. S. Lin and L. K. Felker, J. Phys. Chem., 1991, 95, 3106. 7 A. Sinhal, L. M. Toth, J. S. Lin and K. Affholter, J. Am. Chem. Soc., 1996, 118, 11529. 8 L. A. Chiavacci, S. H. Pulcinelli, C. V. Santilli and V. Briois, Chem. Mater., 1998, 10, 986. 9 M. Aberg and J. Glaser, Inorg. Chim. Acta, 1993, 206, 53. 10 A. Clearfield and P. A. Vaughan, Acta Crystallogr., 1956, 9, 555. 11 A. Clearfield, Rev. Pure Appl. Chem., 1964, 14, 91. 12 A. Clearfield, J. Mater. Res., 1990, 5, 161. 13 T. C. W. Mak, Can. J. Chem., 1968, 46, 3491. 14 M. Falinski, Ann. Chim. (Paris), 1941, 16, 237. 15 D. I. Kochubey, EXAFS-spektroskopiya katalizatorov (EXAFS spectroscopy of catalysts), Nauka, Novosibirsk, 1992 (in Russian). 16 K. V. Klementev, Nucl. Instrum. Methods Phys. Res., Sect. A, 2000, 448, 299. 17 S. J. Gurman, N. Binsted and I. Ross, J. Phys. Chem., 1986, 19, 1845. Received: 2nd A

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 Octacoordinated main-group element centres in a planar cyclic B8 environment: an ab initio study Ruslan M. Minyaev,* Tatyana N. Gribanova, Andrei G. Starikov and Vladimir I. Minkin Institute of Physical and Organic Chemistry, Rostov State University, 344090 Rostov-on-Don, Russian Federation. Fax: +7 8632 43 4667; e-mail: minyaev@ipoc.rsu.ru 10.1070/MC2001v011n06ABEH001496 Density functional theory [B3LYP/6-311G(2df)] calculations predict stable planar structures of the nonclassical compounds XB8 (X = Si, P+) containing central octacoordinated silicon and phosphorus atoms, and a fluxional structure of CB8 with effective octacoordination of the carbon atom.Studies of novel stable structures with non-standard geometries formed by hypercoordinated main-group elements are among the most important tasks of contemporary structural chemistry.1.4 The conditions for stabilization of planar tetracoordinated carbon centres5 have been realised in a variety of organoelement compounds. 6,7 Novel stable systems 1.3 containing planar hexacoordinated carbon2,4 and boron8 centres were recently described using ab initio calculations.The multicentre bonding type found in 1.3 is also expected to be observed in other planar structures with octacoordinated main-group element centres. Here, we report on density functional theory [B3LYP/6- 311G(2df)] calculations of compounds 4 (X = Si, P+), which contain octacoordinated planar silicon and phosphorus centres, and also of their carbon analogue 4 (X = C), which possesses a fluxional structure with effective octacoordination of the planar carbon atom.According to the DFT calculations,¢Ó compounds 4 (X = Si, P+) possess highly symmetrical D8h planar structures and correspond to the minima (l = 0; hereafter, l designates the number of hessian negative eigenvalues at a given stationary point) on the corresponding potential energy surfaces (PES), whereas the D8h structure of 4 (X = C) corresponds to the hilltop (l = 2) on the CB8 PES.Table 1 and Figure 1 demonstrate their geometry and energy characteristics. The energy minimum (l = 0) for the cyclic structure of CB8 is represented by the C2v form of 5 with the pentacoordinated central carbon. The lengths of the B.C bonds formed by the central carbon with the peripheral borons in 5 are equal to 1.590, 1.627 and 1.753 A and are in the range of experimental lengths for a single B.C bond in carboranes.10 The lengths of the peripheral B.B bonds, which are in the range 1.512.1.548 A, are shorter than those observed for double B.B bonds (~1.63 A).11,12 The structure of 5 is highly fluxional and undergoes rapid topomerization according to the scheme 5a 6a 5b 6b 5c ..., where the structures of 6 with C2v symmetry correspond to saddle points (l = 1) on the CB8 PES and serve as true transition states for the low-energy barrier (1.3 kcal mol.1) process in which internal C.B bonds switch sequentially within the cycle.With the account taken for zero point energy, this barrier decreases to 0.9 kcal mol.1.For the more accurate estimation of relative energies of the structures of 4 (X = C), 5 and 6, we performed single point CCSD(fc)/6-311G(2d) calculations of these structures at the B3LYP/6-311G(2df) geometries. As can be seen in Table 1, the relative energies obtained by DFT ¢Ó DFT calculations have been performed with B3LYP functional and with 6-311G(2df) basis sets using the Gaussian-98 program package.9 Geometry optimization was carried out with a ¡®tight¡� key-word.Total energies of the structures of 4 (X = C), 5 and 6 were finally calculated by the CCSD/6-311G(2d) method at the B3LYP/6-311G(2df) geometry. B Y B B B B B X X C C B B B B C X = NH, O; Y = C, B. 1 2 B B B B B B B C C C H H H 3 B B B B B B B B X B B B B B B B B C B B B B B B B B C 4, D8h 5, C2v 6, C2v B3LYP/6-311G(2df) 4 (X = C), D8h (l = 2) 4 (X = Si), D8h (l = 0) 4 (X = P+), D8h (l = 0) 5, C2v (l = 0) 6, C2v (l = 1) 1.509 1.972 1.566 2.038 1.562 2.041 C Si P+ 1.512 1.533 2.499 1.545 2.899 1.753 1.627 1.590 1.548 1.605 1.661 1.542 2.105 1.530 1.515 1.523 1.559 C C Figure 1 Geometry parameters of the structures of 4.6 calculated by the DFT method. The bond lengths are indicated in angstrom units.Table 1 Data of DFT and CCSD calculations for compounds 4.6.a aEtot (in a.u.) is the total energy (1 a.u. = 627.5095 kcal mol.1); l is the number of the negative hessian eigenvalues; .E and .EZPE (in kcal mol.1) are relative energies without and with accounting ZPE; w1/iw (in cm.1) is the smallest or imaginary harmonic vibration frequency. Structure, symmetry Method Etot l .E .EZPE w1/iw 4 (X = C) D8h B3LYP/6-311G(2df) CCSD(fc)/6-311G(2d) .236.578192 .235.766545 2. 17.61 18.00 14.79 . i513(e) . 4 (X = Si) D8h B3LYP/6-311G(2df) .488.132109 0 . . 146 4 (X = P+) D8h B3LYP/6-311G(2df) .539.671526 0 . . 184 5 C2v B3LYP/6-311G(2df) CCSD(fc)/6-311G(2d) .236.606253 .235.795224 0. 00 0 . 87.4 . 6 C2v B3LYP/6-311G(2df) CCSD(fc)/6-311G(2d) .236.604204 .235.791954 1. 1.29 2.05 0.93 . i149 .Mendeleev Communications Electronic Version, Issue 6, 2001 2 and CCSD(fc)/6-311G(2d) methods agree well. A very small value of the energy barrier for the rearrangement 5a 6a 5b 6b 5c ... allows one to consider the fluxional system of 5 as that with the effective octacoordination of the central carbon. In compounds 4 (X = Si, P+) with octacoordinated central silicon and phosphorus centres, the lengths of the BSi and BP bonds were calculated to be 2.038 and 2.041 A.These values exceed slightly the sum of the covalent radii of boron and silicon (1.98 A) or boron and phosphorus (1.91 A), which may be explained as a consequence of the multicentre bonding of the central atoms with the surrounding ligating boron atoms.All compounds 4.6 are aromatic 6¥�-electron systems with three occupied ¥�-orbitals (see Figure 2). According to MO analysis, the ¥�-electron system of 4 contains only 6¥� electrons, four of which furnishing by boron atoms and the other two by the central atom X. In conclusion, our DFT calculations showed that the systems of 4 (X = Si, P+) are the first theoretically predicted examples of stable compounds containing octacoordinated planar silicon and phosphorus atoms.The fluxional structure of 4 (X = C) may be considered as that with an effectively octacoordinated planar carbon centre. This work was supported by the Russian Foundation for Basic Research (grant nos. 01-03-32546 and 00-15-97320). References 1 V. I. Minkin, R. M. Minyaev and Yu. A. Zhdanov, Nonclassical Structures of Organic Compounds, Mir, Moscow, 1987. 2 R. M. Minyaev and T. N. Gribanova, Izv. Akad. Nauk, Ser. Khim., 2000, 786 (Russ. Chem. Bull., 2000, 49, 783). 3 X. Li, A. E. Kuznetsov, H.-F. Zhang, A. I. Boldyrev and L.-S. Wang, Science, 2001, 291, 859. 4 K. Exner and P. v. R. Schleyer, Science, 2000, 290, 1937. 5 R. Hoffmann, R. W. Alder and C. F. Wilcox Jr., J. Am.Chem. Soc., 1970, 92, 4992. 6 K. Sorger and P. v. R. Schleyer, J. Mol. Struct. (Theochem.), 1995, 338, 317. 7 T. N. Gribanova, R. M. Minyaev and V. I. Minkin, Collect. Czech. Chem. Commun., 1999, 64, 170. 8 T. N. Gribanova, R. M. Minyaev and V. I. Minkin, Mendeleev Commun., 2001, 169. 9 M. J. Frisch, G.W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, V. G.Zakrzewski, J. A.Montgomery, Jr., R. E. Stratmann, J. C. Burant, S. Dapprich, J. M. Millam, A. D. Daniels, K. N. Kudin, M. C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski, G. A. Petersson, P. Y. Ayala, Q. Cui, K. Morokuma, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B. Foresman, J. Cioslowski, J. V.Ortiz, A. G. Baboul, B. B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R. L. Martin, D. J. Fox, T. Keith, M. A. Al-Laham, C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill, B. Johnson, W. Chen, M. W. Wong, J. L. Andres, C. Gonzalez, M. Head-Gordon, E. S. Replogle and J. A. Pople, Gaussian 98, Revision A.9, Gaussian, Inc., Pittsburgh PA, 1998. 10 M. Hargittai and I. Hargittai, The Molecular Geometries of Coordinaunds in Vapour Phase, Akademia Kiado, Budapest, 1975. 11 P. Power, Inorg. Chim. Acta, 1992, 198.200, 443. 12 W. J. Grigsby and P. P. Power, Chem. Eur. J., 1997, 3, 368. B B B B B B B B 5a B B B B B B B B 6a B B B B B B B B 5b B B B B B B B B 6b B B B B B B B B 5c E/eV 2 0 .2 .4 .6 .8 .10 .12 Figure 2 Occupation and shape of ¥�-orbitals in compound 4. Received: 6th July 2001; Com. 01/18

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 Synthesis of crown ether–substituted yttrium(III) bisphthalocyanine Yuliya G. Gorbunova,* Lyudmila A. Lapkina, Svetlana V. Golubeva, Vladimir E. Larchenko and Aslan Yu. Tsivadze N. S. Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 119991 Moscow, Russian Federation. Fax: + 7 095 954 5483; e-mail: yulia@igic.ras.ru 10.1070/MC2001v011n06ABEH001507 A double-decker complex of yttrium(III) with tetra-15-crown-5-phthalocyanine has been synthesised and characterised by spectroscopic methods.The chemistry of rare earth phthalocyanines is of interest for the development of new functional materials because the sandwich double-decker monoradical complexes of rare earth elements exhibit unique optical and physical properties.1–3 The syntheses and functional properties of lanthanide phthalocyanines were described in the literature; however, only a few works were devoted to yttrium phthalocyanines.4–6 Yttrium complexes with unsubstituted phthalocyanine (Pc) with the composition [Y3+]:[Pc2–] = = 1:1, 1:2 and 2:3 were synthesised4,5 by a template method in an o-phthalonitrile melt with the addition of yttrium acetate.Y(Pc)2 · was also prepared by refluxing Li2(Pc) and Y(acac)·3H2O in 1,2,4-trichlorobenzene for 10 h in a nitrogen atmosphere.6 Y[Pc(C7H15)8]2 · and Y[Pc(OC5H11)8]2 · were synthesised by the interaction of Y(acac)·3H2O with corresponding 4,5-disubstituted phthalonitriles in the presence of 1,8-diazabicyclo[5.4.0]- undec-7-ene (DBU) in amyl alcohol under reflux for 12 h under nitrogen.6 The double-decker lutetium phthalocyanine complexes described earlier,7 in which crown-ether substituents are an integrated part of the macrocyclic phthalocyanine ring, can exhibit the cationinduced organisation of supramolecular assemblies, which are superior to similar compounds with other substituents in the electrophysical characteristics.7 Crown ether–substituted yttrium phthalocyanines were not described previously. The synthesis of lanthanide crown phthalocyanines by the direct interaction of H2R4Pc [R4Pc2– = 4,5,4',5',4'',5'',4''',5'''-tetrakis- (1,4,7,10,13-pentaoxatridecamethylene)phthalocyaninate ion] with a metal salt in the presence of a strong base was used for obtaining Y3+ complexes with tetra-15-crown-5-phthalocyanine.8,9 This synthetic method allowed us to prepare complexes of a given structure; the reaction was performed in a boiling solvent to obtain mono- (in 1,2-dichlorobenzene) or multi-decker compounds (in 1-chloronaphthalene).The synthesis was performed starting from H2R4Pc, which was synthesised according to a described procedure,10 and Y(OAc)3·4H2O in the presence of DBU as an organic base in 1-chloronaphthalene under reflux (260 °C) in an argon atmosphere. Optimum conditions for the complete transformation of the initial ligand into metal complexes were chosen by varying the main parameters of the synthesis (the molar ratio between reactants and the ligand concentration).The conversion was monitored by electronic absorption spectroscopy.The complete transformation of H2(R4Pc) into an Y3+ complex took place after 2 h at an Y(OAc)3·4H2O:H2R4Pc:DBU molar ratio of 1.5:1:13 and a ligand concentration of 2×10–2 mol dm–3. The double-decker Y(R4Pc)2 · complex was separated by liquid column chromatography on Al2O3 (eluent: CHCl3–MeOH, 98:2 by volume) with 20% yield. The structure of the separated complex was found from the parameters of the UV-VIS spectrum† in chloroform, which were characteristic of sandwich lanthanide crown-bisphthalocyanines.8 The dark green crystalline powder obtained is soluble in polar organic solvents.Table 1 summarises data on the UV-VIS spectrum of the prepared compound and published data on the spectra of double-decker complexes of Lu, Yb and Gd with tetra-15-crown-5-phthalocyanine.A comparative analysis of these data allowed us to conclude that the synthesised complex has a double-decker structure. We studied the concentration dependence of the intensities of the main bands in the UV-VIS spectrum of Y(R4Pc)2 · in chloroform and found that the Bouguer–Lambert–Beer law is obeyed up to a concentration of 2.5×10–4 mol dm–3.A negative deviation from linearity was observed in more concentrated solutions as a consequence of aggregation processes. The structure of the prepared complex was also supported by FAB mass spectrometry. The mass spectrum exhibited a signal with m/z 2635.9, which corresponds to the molecular ion [Y(R4Pc)2]+ (the calculated value of m/z is 2635.5). We measured the EPR‡ spectrum of the compound to confirm its radical nature.The presence of a singlet signal with g = 2.0031 in the EPR spectrum of a chloroform solution of the compound is caused by an unpaired electron in the molecule of [(R4Pc2–)Y3+(R4Pc– · )]0. We also measured the electronic absorption spectrum in the near-IR region.§ The presence of absorption bands at 920, 1430 and 1560 nm, which are ascribed12 to the donor–acceptor exchange interaction between the Pc2– dianion and the Pc– · radical monoanion, also confirms the radical nature of the complex. † The UV-VIS spectra were measured on a Varian Cary-100 instrument.‡ The EPR spectrum was measured by Dr. G. A. Zvereva on a Radiopan SE-X-2542 spectrometer at room temperature. § The near-IR spectrum was measured by Dr. A.S. Lileev on a Specord NIR-61 instrument (Carl Zeiss Jena). N NH N N N N HN N O O O O O O O O O O O O O O O O O O O O Y(OAc)3, DBU 260 °C Y Y(R4Pc)2 Table 1 UV-VIS spectra of the double-decker complexes of Y, Gd, Yb and Lu with tetra-15-crown-5-phthalocyanine in chloroform. Y(R4Pc)2 · lmax/nm (lg e) Gd(R4Pc)2 · lmax/nm (lg e)8 Yb(R4Pc)2 · lmax/nm (lg e)8 Lu(R4Pc)2 · lmax/nm (lg e)11 670 (5.01) 675 (5.08) 670 (5.18) 665 (5.20) 481 (4.48) 488 (4.53) 479 (4.60) 476 (4.66) 368 (5.01) 368 (5.00) 369 (5.12) 367 (5.13) 334 (4.92) 337 (4.93) 292 (4.93) 292 (4.96) 292 (5.06)Mendeleev Communications Electronic Version, Issue 6, 2001 2 The intense bands at 1278, 1202, 1126, 1103 and 935 cm–1 present in the vibration IR spectrum¶ of the synthesised complex (as a Nujol mull), which are assigned to the stretching vibrations of crown ether fragments,8,13 provide support for the presence of these substituents in phthalocyanine ligands.Thus, we performed the directed synthesis of the yttrium complex Y(R4Pc)2 · with tetra-15-crown-5-phthalocyanine ligands of the composition 1:2. The structure of the complex was confirmed by UV-VIS, IR and EPR spectroscopy and FAB mass spectrometry. This work was supported by the Russian Foundation for Basic Research (grant nos. 99-03-32644, 00-15-97377 and 01-03-06241). References 1 P. N. Moskalev, Koord. Khim., 1990, 16, 147 [Sov. J. Coord. Chem. (Engl. Transl.), 1990, 16, 77]. 2 M. M. Nicholson, in Phthalocyanines. Properties and Application, eds. C. C. Leznoff and A. B. P. Lever, VCH, New York, 1993, vol. 3, p. 71. 3 C. Ercolani, J. Porphyrins Phthalocyanines, 2000, 4, 340. 4 K. Kasuga, M. Ando and H. Morimotto, Inorg. Chim. Acta, 1986, 112, 99. 5 K. Kasuga, M. Ando, H. Morimotto and M. Isa, Chem. Lett., 1986, 1095. 6 J. Jiang, J. Xie, M. Choi, Y. Yan and S. Sun, J. Porphyrins Phthalocyanines, 1999, 3, 322. 7 T. Toupance, V. Ahsen and J. Simon, J. Am. Chem. Soc., 1994, 116, 5352. 8 L. A. Lapkina, E. Niskanen, H. Ronkkomaki, V. E. Larchenko, K. I. Popov and A. Yu. Tsivadze, J. Porphyrins Phthalocyanines, 2000, 4, 587. 9 L. A. Lapkina, V. E. Larchenko, E. O. Tolkacheva, K. I. Popov, N. Yu. Konstantinov, V. M. Nosova and A. Yu. Tsivadze, Zh. Neorg. Khim., 1998, 43, 987 (Russ. J. Inorg. Chem., 1998, 43, 901). 10 V. Ahsen, E. Yilmazer, M. Ertas and O. Bekaroglu, J. Chem. Soc., Dalton Trans., 1988, 401. 11 E. O. Tolkacheva, A. Yu. Tsivadze, Sh. G. Bitiev, Yu. G. Gorbunova, V. I. Zhilov and V. V. Minin, Zh. Neorg. Khim., 1995, 40, 984 (Russ. J. Inorg. Chem., 1995, 40, 949). 12 D. Markovitsi, T. H. Tran-Thi, R. Even and J. Simon, Chem. Phys. Lett., 1987, 137, 107. 13 E. O. Tolkacheva, L. A. Demina, A. Yu. Tsivadze, Sh. G. Bitiev and V. I. Zhilov, Zh. Neorg. Khim., 1995, 40, 449 (Russ. J. Inorg. Chem., 1995, 40, 432). ¶ The IR spectrum was measured on a Nexus spectrometer (Nicolet). Received: 25th July 2001; Com. 01/1833

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 Design and synthesis of paclitaxel-containing aminoester phosphate and phosphoamidate Jih Ru Hwu,*a,b Shwu-Chen Tsay,b Thota Sambaiah,a Yiu-Kay Lai,c Chien-Hui Lieu,c Gholam H. Hakimelahib and Ke-Yung Kinga,b a Organosilicon and Synthesis Laboratory, Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China.Fax: +886 3 572 1594; e-mail: jrhwu@mx.nthu.edu.tw b Institute of Chemistry, Academia Sinica, Nankang, Taipei, Taiwan 11529, Republic of China c Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China 10.1070/MC2001v011n06ABEH001498 Paclitaxel-containing aminoester phosphate 4 and phosphoamidate 9 were synthesised and found to possess anticancer activity against HL-60 leukemia cells; their solubility in a phosphate buffer solution was about 16 times higher than that of paclitaxel. Paclitaxel 1 is one of the most promising anticancer agents;1 it inhibits cell division and other interphase processes by stabilising microtubules.2–6 This anticancer agent has an extremely low solubility in water.4,5 Thus, enormous efforts have been focused on the modification of paclitaxel in order to create more watersoluble and, consequently, more easily formulated and delivered drugs.7 New paclitaxel derivatives could be designed to convert, in a predictable fashion, into the original active drug by either an enzymic mechanism8–12 or simple hydrolysis initiated under physiological pH conditions.13 Most accounts to date for paclitaxel 1 have been concerned with its esterifications at the C-2' 7,11,14–21 or C-711,22–25 hydroxyl group for improvement of the water solubility while the cytotoxic activity is maintained. 7,14–19,21–23,25 In general, dephosphorylation occurs easier in cancer cells than in normal cells. Thus, chemotherapeutic agents possessing a phosphate or phosphoamidate unit would preferentially interact with the cancer cells.26 Given these phenomena, we designed and synthesised new paclitaxel-containing aminoester phosphate 4 (Scheme 1) and phosphoamidate 9 (Scheme 2)27 with higher water solubility.These new propaclitaxel analogues were found to possess anti-leukemic activity slightly greater than that of paclitaxel. To synthesise 2'-[4-(N,N-dimethylammonium)butyryl]paclitaxel 7-phosphate 4, we condensed paclitaxel 1 with 4-(N,N-dimethylamino) butyric acid 2 in the presence of dicyclohexylcarbodiimide (DCC) and a catalytic amount of (dimethylamino) pyridine (DMAP) in CH2Cl2 at 25 °C (Scheme 1).† Corresponding amino ester 3 was obtained in 88% yield.The reaction of 3 with P(OMe)Cl2 in the presence of collidine in THF at 0 °C and then with I2 and water at 25 °C produced the target compound, ammonium ester phosphate 4, in 90% yield.27 Compound 4 existed in its zwitterionic form.For the preparation of 2'-[3-(phosphoamido)propionyl]paclitaxel 9, we treated paclitaxel 1 with 3-(N-monomethoxytritylamino) propionic acid 6 in the presence of DCC and DMAP in CH2Cl2 at 25 °C to give monomethoxytritylated amino ester 7 in 95% yield (Scheme 2).‡ Compound 7 in wet acetonitrile was treated with a catalytic amount of ceric ammonium nitrate (CAN) at 25 °C to afford detritylated amino ester 8 in 97% yield.28 The reaction of 8 with P(OMe)Cl2 and collidine in THF and then with I2 and water produced desired phosphoamidate 9 in 85% yield.27 † The structure of compound 3 was confirmed by the 1H NMR (CDCl3, 300 MHz) spectrum, which showed characteristic peaks at d 2.17 (s, 6H, 2NMe) and 5.50 (d, 1H, 2'-H, J 3.2 Hz).Compound 4 showed characteristic peaks in 1H NMR (CDCl3, 300 MHz) d: 5.07 (dd, 1H, 7-H, J 10.7, 6.4 Hz) and 7.11 (br. d, 1H, NH). ‡ The structure of compound 7 was confirmed by the 1H NMR (CDCl3, 300 MHz) spectrum, which showed characteristic peaks at d 3.75 (s, 3H, OMe) and 5.68 (d, 1H, 2'-H, J 7.1 Hz).Compound 8 showed a characteristic peak in 1H NMR (CDCl3, 300 MHz) d: 3.14 (br. s, 2H, NH2). Compound 9 showed a characteristic peak in 1H NMR (CDCl3, 300 MHz) d: 7.03 (d, 1H, NH, J 7.6 Hz). Scheme 1 OH O O O O O O O O OH N O OH H O O H 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 2' 3' NMe2 O OH 1 2 DCC, DMAP CH2Cl2, 25 °C (88%) OH O O O O O O O O O N O OH H O O H 7 2' 3 O Me2N i, P(OMe)Cl2, collidine, THF, 0 °C O O O O O O O O O O N O OH H O O H 7 2' 4 O Me2N ii, I2, H2O, 25 °C (90%) P OH O O H physiological O O O O O O O O O OH N O OH H O O H 7 2' 5 pH buffer P OH O OMendeleev Communications Electronic Version, Issue 6, 2001 2 The solubility (µmol dm–3) in a phosphate buffer solution (0.10 M, pH 6.5) was 896 for 4, 952 for 9 and 57.8 for paclitaxel 1.Paclitaxel-containing aminoester phosphate 4 and phosphoamidate 9 were tested in vitro against HL-60 leukemic cells.29,30 The IC50 values (µmol dm–3) were 4.0×10–3 for 4, 3.8×10–3 for 9 and 4.5×10–3 for 1. In comparison with paclitaxel 1, new compounds 4 and 9 were found ~16 times more soluble in a phosphate buffer solution, and they exhibited comparable anti-leukemic activities in vitro. The free C(2')–OH group is essential for the anticancer activity of paclitaxel.27 Therefore, hydrolysis of the ester component in 4 and 9 under physiological pH conditions to give 5 and 1, respectively, is responsible for the anti-leukemic activity of these new paclitaxel derivatives.On the other hand, the C(7)- phosphate functionality in 5 cannot be hydrolysed in vitro where phosphoesterases are not present.Thus, the C(7)-phosphate derivative of paclitaxel (i.e., 5) possesses anti-leukemic activity comparable with that of paclitaxel 1. This work was supported by the National Health Research Institutes of the Republic of China and Academia Sinica. References 1 (a) D. G. I. Kingston, Chem. Commun., 2001, 867; (b) S.Sangrajrang and A. Fellous, Chemotherapy, 2000, 46, 327; (c) C. A. Hudis, Semin. Oncol., 1999, 26, 1; (d) D. M. Shin and S. M. Lippman, Semin. Oncol., 1999, 26, 100; (e) L. M. Weiner, Semin. Oncol., 1999, 26, 106; (f) A. Younes, Semin. Oncol., 1999, 26, 123; (g) E. K. Rowinsky and R. C. Donehower, New Engl. J. Med., 1995, 332, 1004. 2 P. B. Schiff, J. Fant and S.B. Horwitz, Nature, 1979, 277, 665. 3 P. B. Schiff and S. B. Horwitz, Proc. Natl. Acad. Sci., USA, 1980, 77, 1561. 4 E. K. Rowinsky, L. A. Cazenave and R. C. Donehower, J. Natl. Cancer Inst., 1990, 82, 1247. 5 F. A. Holmes, R. S.Walters, R. L. Theriault, A. D. Forman, L. K. Newton, M. N. Raber, A. U. Buzdar, D. K. Frye and G. N. Hortobagyi, J. Natl. Cancer Inst., 1991, 83, 1797. 6 R. Oliyai and V. J. Stella, Annu. Rev. Pharmacol. Toxicol., 1993, 33, 521. 7 R. B. Greenwald, C. W. Gilbert, A. Pendri, C. D. Conover, J. Xia and A. Martinez, J. Med. Chem., 1996, 39, 424; and references therein. 8 K. C. Nicolaou, R. K. Guy, E. N. Pitsinos and W. Wrasidlo, Angew. Chem., 1994, 106, 1672 (Angew. Chem., Int. Ed. Engl., 1994, 33, 1583). 9 G. H. Hakimelahi, A. A. Moosavi–Movahedi, M.M. Sadeghi, S.-C. Tsay and J. R. Hwu, J. Med. Chem., 1995, 38, 4648. 10 M. A. Jordon and L. Wilson, in Taxane Anticancer Agents, eds. G. I. Georg, T. T. Chen, I. Ojima and D. M. Vyas, ACS Symposium Series 583, American Chemical Society, Washington, DC, 1995, p. 124. 11 J. Golik, H. S. L. Wong, S. H. Chen, T. W. Doyle, J. J. Kim Wright, J. Knipe, W. C. Rose, A.M. Casazza and D. M. Vyas, Bioorg. Med. Chem. Lett., 1996, 6, 1837. 12 F. M. H. de Groot, L. W. A. van Berkom and H. W. Scheeren, J. Med. Chem., 2000, 43, 3093. 13 K. C. Nicolaou, C. Riemer, M. A. Kerr, D. Rideout and W. Wrasidlo, Nature, 1993, 364, 464. 14 H. M. Deutsch, J. A. Glinski, M. Hernandez, R. D. Haugwitz, V. L. Narayanan, M. Suffness and L. H. Zalkow, J. Med. Chem., 1989, 32, 788. 15 C. S. Swindell, N. E. Krauss, S. B. Horwitz and I. Ringel, J. Med. Chem., 1991, 34, 1176. 16 A. E. Mathew, M. R. Mejillano, J. P. Nath, R. H. Himes and V. J. Stella, J. Med. Chem., 1992, 35, 145. 17 R. B. Greenwald, A. Pendri, D. Bolikal and C. W. Gilbert, Bioorg. Med. Chem. Lett., 1994, 4, 2465. 18 Y. Ueda, H. Wong, J. D. Matiskella, A. B. Mikkilineni, V. Farina, G. Fairchild, W.C. Rose, S. W. Mamber, B. H. Long, E. H. Kerns, A. M. Casazza and D. M. Vyas, Bioorg. Med. Chem. Lett., 1994, 4, 1861. 19 D. B. A. de Bont, R. G. G. Leenders, H. J. Haisma, I. van der Meulen- Muileman and H. W. Scheeren, Bioorg. Med. Chem., 1997, 5, 405. 20 Y. L. Khmelnitsky, C. Budde, J. M. Arnold, A. Usyatinsky, D. S. Clark and J. S. Dordick, J. Am. Chem. Soc., 1997, 119, 11554. 21 E.W. P. Damen, P. H. G.Wiegerinck, L. Braamer, D. Sperling, D. de Vos and H. W. Scheeren, Bioorg. Med. Chem., 2000, 8, 427. 22 D. M. Vyas, H. Wong, A. R. Crosswell, A. M. Casazza, J. O. Knipe, S. W. Mamber and T. W. Doyle, Bioorg. Med. Chem. Lett., 1993, 3, 1357. 23 R. B. Greenwald, A. Pendri and D. Bolikal, J. Org. Chem., 1995, 60, 331. 24 Y. Ueda, J. D. Matiskella, A. B. Mikkilineni, V.Farina, J. O. Knipe, W. C. Rose, A. M. Casazza and D. M. Vyas, Bioorg. Med. Chem. Lett., 1995, 5, 247. 25 T. Takahashi, H. Tsukamoto and H. Yamada, Bioorg. Med. Chem. Lett., 1998, 8, 113. 26 H. Dugas and C. Penney, in Bioorganic Chemistry, A Chemical Approach to Enzyme Action, ed. C. R. Cantor, Springer–Verlag, Berlin, 1981, p. 36. 27 J. R. Hwu, G. H. Hakimelahi, T.Sambaiah, H. V. Patel, S.-C. Tsay, Y.-K. Lai and C.-H. Lieu, Bioorg. Med. Chem. Lett., 1997, 7, 545. 28 J. R. Hwu, M. L. Jain, S.-C. Tsay and G. H. Hakimelahi, J. Chem. Soc., Chem. Commun., 1996, 545. 29 A. Monks, D. Scudiero, P. Skehan, R. Shoemaker, K. Paull, D. Vistica, C. Hose, J. Langley, P. Cronise, A. Vaigrowolff, M. Graygoodrich, H. Campbell, J. Mayo and M. Boyd, J. Natl. Cancer Inst., 1991, 83, 757. 30 P. Skehan, R. Storeng, D. Scudiero, A. Monks, J. McMahon, D. Vistica, J. T. Warren, H. Bokesch, S. Kenney and M. R. Boyd, J. Natl. Cancer Inst., 1990, 82, 1107. Scheme 2 MMTr N O OH 1 6 DCC, DMAP CH2Cl2, 25 °C (95%) OH O O O O O O O O O N O OH H O O H 2' 7 O NH MMTr CAN, MeCN OH O O O O O O O O O N O OH H O O H 2' 8 O H2N 25 °C (97%) OH O O O O O O O O N O OH H O O H 2' 9 H i, P(OMe)Cl2, collidine, THF, 0 °C ii, I2, H2O, 25 °C (85%) O O NH P O OH HO C OMe 2 MMTr = Received: 9th July 2001; Com. 01/1824

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 The transphosphorylation of â-cyclodextrin perphosphites: a new supramolecular property Alexey E. Glazyrin, Galina I. Kurochkina, Mikhail K. Gratchev and Edward E. Nifantiev* Department of Chemistry, Moscow State Pedagogical University, 119021 Moscow, Russian Federation. E-mail: chemdept@mtu-net.ru 10.1070/MC2001v011n06ABEH001487 â-Cyclodextrin perphosphite 1, R = 5,5-dimethyl-1,3,2-dioxaphosphorinan-2-yl, exhibits an unusual transphosphorylation reaction with chlorophosphites; the inclusion of adamantane into the cyclodextrin cavity substantially inhibits this reaction.Cyclodextrins are of interest to organic chemistry because of their great potential in synthetic applications,1 as well the possibility of designing novel supramolecular architectures exploiting the intramolecular chiral hydrophobic cavities of these compounds. 2 However, the role played by the cyclodextrin cavity in binding and chemical transformations is not clearly understood. In particular, such considerations have played little part in the analysis of the transformation of organophosphorus compounds in contact with cyclodextrins. In this context, we examined the chemical properties of â-cyclodextrin perphosphite 1, R = 5,5- dimethyl-1,3,2-dioxaphosphorinan-2-yl, and found that it has a tendency to undergo transphosphorylation during its interaction with chlorophosphites.3 Note that such a reaction was previously unknown: the phosphites of carbohydrates and related compounds do not enter into such reactions. Thus, the transphosphorylation of â-cyclodextrin perphosphites is an unique phenomenon and, therefore, we aimed to investigate its chemical nature.We assumed that a transphosphorylating reagent could be included in the cyclodextrin cavity and then transformed at a supramolecular level. This transformation consists in bringing together the covalently bound phosphite groups of host and guest molecules followed by the redistribution of the bonds to form new perphosphites of â-cyclodextrin.The resulting â-cyclodextrin products have more compact substituents and hence are more stable compounds. To test this hypothesis on the mechanism of transphosphorylation, we performed transphosphorylation in the presence of adamantane. It is well known that the structure and size of an adamantane molecule fit to the structure and size of the cavity of â-cyclodextrin (and many its derivatives); therefore, â-cyclodextrins readily form stable inclusion compounds with adamantane. 4 Evidently, analogous adamantane inclusion compounds from â-cyclodextrin perphosphites 1 would not permit the inclusion of a transphosphorylating agent. Since this experiment showed that adamantane ‘turned off’ the transphosphorylation reaction, the hypothesis on the supramolecular aspects of the original transphosphorylation reaction was confirmed experimentally.The course of the transformation was quantitatively monitored by 31P NMR spectroscopy. The integration of appropriate signals showed the accumulation of chlorophosphite 3 (147 ppm) and the redistribution of the initial signals of the phosphorus-containing residues in initial compound 1 (121 ppm) and product 4 (121 and 135 ppm).We found that, in the absence of adamantane, the reaction proceeded by 60% at 20 °C after 2 h and by 80% at 60 °C after 1 h (although no further reaction then occured).† Under the same conditions in the presence of 2 equiv. of adamantane, the reaction proceeded by only 5% and even after heating at 80 °C for 72 h the transphosphorylation proceeded by only 20%.‡ In a separate experiment, we found that the transphosphorylation of â-cyclodextrin perphosphite 1, R = 5,5-dimethyl-1,3,2- dioxaphosphorinan-2-yl, also occurs with other chlorocyclophosphites, namely, 2-chloro-4,5-dimethyl-1,3,2-dioxaphospholane 5, 2-chloro-4-methyl-1,3,2-dioxaphosphorinane 6 and 2-chloro- 4,4,5,5-tetramethyl-1,3,2-dioxaphospholane.In these cases, the extent of reaction was 60, 50 or 40%, respectively (at 60 °C for 1 h). Unexpected results were obtained in the transphosphorylation with an equimolecular mixture of two chlorophosphites 2 and 6 (1:1).§ In this case, the reaction slows down sharply: according † Chlorophosphite 2 (0.27 g, 2.1 mmol) was added to a solution of perphosphite 1 (0.39 g, 0.1 mmol) in 10 ml of benzene at 25 °C with stirring. The 31P NMR spectrum of the reaction mixture (25 °C, 2 h) d: 168 (2) and 147 (3), 134, 122 (4) in an integral ratio of 2:3:3:2; (60 °C, 1 h) d: 168 (2) and 147 (3), 134, 122 (4) in an integral ratio of 1:4:4:1.‡ Chlorophosphite 2 (0.27 g, 2.1 mmol) was added to a solution of perphosphite 1 (0.39 g, 0.1 mmol) and adamantane (0.027 g, 0.2 mmol) in 10 ml of benzene at 25 °C with stirring. The 31P NMR spectrum of the reaction mixture (25 °C, 2 h) d: 168 (2) and 147 (3), 134, 122 (4) in an integral ratio of 19:1:1:19; (60 °C, 1 h) d: 168 (2) and 147 (3), 134, 122 (4) in an integral ratio of 4:1:1:4.§ Chlorophosphites 2 and 6 (2.1 mmol of each) were added to a solution of perphosphite 1 (0.39 g, 0.1 mmol) in 10 ml of benzene at 25 °C with stirring.(OR)7 (OR)7 (OR)7 (OR)7 (OR)7 (OR)7 O P O Cl 21 2 1 < 0.1% > 99.9% O P O Cl 21 2 (OR')x(OR)7–x 4 O O P Cl (x + y + z) 3 (OR)7 (OR)7 (OR)7 O P O Cl 21 2 (OR')x(OR)7–x R Cl 3 P Cl 21 6 O OMendeleev Communications Electronic Version, Issue 6, 2001 2 to 31P NMR data, the signal of chlorophosphite 3 appears only after heating at 80 °C for 24 h.We presume that this phenomenon is due to competition between chlorophosphites 2 and 6 at both steps (a and b) needed for the transphosphorylation: namely, the inclusion into a cyclodextrin cavity (a) and the interaction with neopentylenephosphite residues (b). This supposition is confirmed by the fact that the use of the same conditions with an equimolecular mixture of two chlorophosphites 5 and 6 does not inhibit the reaction (50% substitution after 2 h at 60 °C).¶ This can be explained by an increased affinity of chlorophosphite 5, in comparison with 2, for the cyclodextrin cavity.Here, the difference in the strength of the inclusion compounds from the former and latter reagents is not as great, and the reaction proceeds normally.Therefore, we can conclude that the discovered transphosphorylation of per-PIII-containing cyclodextrins 1, R = 5,5- dimethyl-1,3,2-dioxaphosphorinan-2-yl is, probably, a result of complex supramolecular interactions between cyclodextrin derivatives and chlorophosphites. References 1 (a) J. Szejtli, Chem.Rev., 1998, 98, 1743; (b) A. R. Khan, P. Forgo, K. J. Stine and V. T. D’Souza, Chem. Rev., 1998, 98, 1977; (c) K. Takanashi, Chem. Rev., 1998, 98, 2013; (d) A. R. Hedges, Chem. Rev., 1998, 98, 2035; (e) K. Uekama, F. Hirayama and T. Irie, Chem. Rev., 1998, 98, 2045. 2 G. Wenz, Angew. Chem., Int. Ed. Engl., 1994, 33, 803. 3 E. E. Nifantiev, A. E. Glazyrin, G. I. Kurochkina and M. K. Gratchev, Zh. Obshch. Khim., 2000, 70, 1752 (Russ. J. Gen. Chem., 2000, 70, 1649). 4 M. R. Eftink, M. L. Andy, K. Bystrom, H. D. Perlmutter and D. S. Kristol, J. Am. Chem. Soc., 1989, 111, 6765. (OR)7 (OR)7 (OR)7 O P O Cl 21 5 (OR')x(OR)7–x R Cl 3 P Cl 21 6 O O ¶ Chlorophosphites 5 and 6 (2.1 mmol of each) were added to a solution of perphosphite 1 (0.39 g, 0.1 mmol) in 10 ml of benzene at 25 °C with stirring. Received: 18th June 2001; Com. 01/1813

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Mendeleev Communications Electronic Version, Issue 6, 2001 1 Complexation of (1-diphenylphosphino)cyclopropanecarbonitrile with palladium(II) Natalya M. Vinogradova, Irene L. Odinets,* Konstantin A. Lyssenko, Margarita P. Pasechnik, Pavel V. Petrovskii and Tatyana A. Mastryukova A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 119991 Moscow, Russian Federation. Fax: +7 095 135 5085; e-mail: odinets@ineos.ac.ru 10.1070/MC2001v011n06ABEH001515 (1-Diphenylphosphino)cyclopropanecarbonitrile 1 was synthesised by the reduction of a phosphine oxide; the interaction of 1 with (PhCN)2PdCl2 leads to 1:1 or 1:2 complexes depending on the ratio between the reactants.Functionalised phosphine ligands are of considerable interest because of their unusual complexing properties.Ligands containing phosphorus and nitrogen complexing centres are of special interest, because catalytic systems based on such ligands show high activity in many reactions.1.5 Furthermore, palladium organonitrile complexes (with coordination via the nitrogen atom of a cyano group) are known as carbonylation catalysts,5 e.g., for highly selective formation of 1,5-diphenylpentan-3-one from styrene by hydroformylation.Among these complexes are those containing separate phosphine and organonitrile ligands.5,6 Mono-, bis- and tris-¥â-cyanoethyl-substituted phosphines were obtained by the cyanoethylation of phosphines.7 The nickel8 and molibdenum9 complexes of tris(¥â-cyanoethyl)phosphine (CEP) having three-dimensional polymeric structures are known. In these complexes, the metals are coordinated via the nitrogen atom of a cyanoethyl group.However, in the crystalline complexes Mo2Cl4(CEP)2(RCN)2 (R = Me, Et and Pri), coordination of nitrile groups to molybdenum was not observed.9 As for ¥á-cyanosubstituted phosphines, a few representatives of the simplest linear cyanomethylphosphines were prepared by the reduction of phosphine oxides with diphenylsilane,10 or of phosphine sulfide with nickel powder11 and by the reaction of silylphosphines with chloroacetonitrile.12 The complexing properties with a variety of metals (NiII, Fe0, AuI, PtII, PdII and RhIII) were investigated only for cyanomethyldiphenylphosphine, and it was found that the nitrogen atom of the cyano group is not involved in the coordination.12 It was reasonable to suggest that the replacement of a methylene group in the above cyanomethyldiphenylphosphine by a cycloalkyl moiety would result in a rigid ligand structure, which is suitable for bidentate coordination with the participation of a nitrogen centre.Moreover, the phosphorus atom in such a ligand exhibits higher nucleophilicity due to the positive inductive effect of the cycloalkyl substituent.The synthesis of (1-diphenylphosphino)cyclopropanecarbonitrile 1¢Ó (L) was carried out by the reduction of phosphine oxide 2¢Ô with an excess of trichlorosilane in quantitative yield according to NMR data and 95% after isolation. Phosphine 1 is a low-melting waxy solid, which is stable in argon for a long time. Depending on the ratio between reactants, the reaction of 1 with trans-dichloro(dibenzonitrile)palladium 3 in a C6H6 solution leads to the formation of the 1:1 ML or 1:2¡× ML2 complex.These complexes precipitated from the reaction solutions after ~10 min as fine orange (ML) or yellow (ML2) crystals. The structure of the complexes was confirmed by IR and 1H, 31P NMR¢Ò (5) spectroscopy and X-ray diffraction analysis.An insignificant shift of the CN absorption band in the IR spectra of 4 and 5 (.nCN 8 cm.1 for 4, .nCN 10 cm.1 for 5) means that the nitrogen atom is not involved in the coordination with palladium. The complexation of phosphine with palladium results in a considerable downfield shift in the 31P NMR spectra (.dP 18 ppm ¢Ó Synthesis of 1: To a solution of (1-diphenylphosphoryl)cyclopropanecarbonitrile 2 (0.48 g, 1.87 mmol) in benzene (120 ml) trichlorosilane (9.35 mmol) was added.After reflux in an argon atmosphere for 15 h, the reaction mixture was cooled and evaporated to dryness. Acetonitrile (50 ml) was added to the residue and the formed precipitate of polymeric siloxane was filtered off. After removing the solvent from the filtrate, 0.45 g (95%) of phosphine 1 was obtained as a low-melting waxy substance, 100% pure according to 1H and 31P NMR. 1HNMR (400.26MHz, CDCl3) d: 1.33.1.39 (m, 2H, CH2), 1.60.1.64 (m, 2H, CH2), 7.41.7.42 (6H, o-H, p-H in Ph), 7.53.7.58 (4H, m-H in Ph). 13C NMR (100.68 MHz, CDCl3) d: 5.64 (d, P.C.CN, 1JPC 24.1 Hz), 14.49 and 14.65 (2s, CH2), 121.27 (CN), 128.37 (d, 3JPC 4.8 Hz), 129.26, 132.31, 132.50, 132.63, 134.53 (d, 1JPC 8.8 Hz). 31P NMR (162.02 MHz, CDCl3) d: 12. IR (KBr, n/cm.1): 2228 (CN). Analysis of the corresponding phosphonium salt with methyl iodide [mp 162.163 ¡ÆC, 31P NMR (CDCl3) d: 33.3]: found (%): C, 51.84; H, 4.21; N, 3.51; calc. for C17H17NPI (%): C, 51.91; H, 4.33; N, 3.56. ¢Ô (1-Diphenylphosphoryl)cyclopropanecarbonitrile 2 was obtained by the cycloalkylation of diphenylphosphorylacetonitrile by 1,2-dibromoethane under phase-transfer catalysis conditions.13 Selected data for 2: yield 61%, mp 168.169 ¡ÆC (EtOH.acetone). 1H NMR (400.26MHz, CDCl3) d: 1.60. 1.65 (m, 2H, CH2), 1.81.1.86 (m, 2H, CH2), 7.52.7.54, 7.61.7.66, 7.83. 7.89 (10H, Ph). 13C NMR (100.68 MHz, CDCl3) d: 6.66 (d, P.C.CN, 1JPC 99.5 Hz), 13.19 (CH2), 119.94 (d, CN, 2JPC 9.1 Hz), 129.44 (d, P.C in Ph, 1JPC 107.7 Hz), 128.45, 128.58, 131.28, 131.37, 132,62, 132.64 (CH in Ph). 31P NMR (162.02 MHz, CDCl3) d: 27.7. IR (KBr, n/cm.1): 1195 (P=O), 2233 (CN). Found (%): C, 71.94; H, 5.12; N, 5.11. Calc. for C16H14NOP (%): C, 71.91; H, 5.24; N, 5.24. ¡× Synthesis of palladium complexes 4 and 5. To a filtered solution of PdCl2(PhCN)2 16 3 (0.38 mmol) in benzene (25 ml) phosphine 1 (0.38 mmol in the case of 4, 0.76 mmol in the case of 5) was added under argon at 20 ¡ÆC.Orange (4) or yellow (5) crystals of the target complex were precipitated in 30 min. The complexes were filtered off to give solvates with benzene molecules (X-ray data) and subsequently dried in vacuo (1 h, 20 ¡ÆC, 1 Torr) to yield solvent-free complexes. Selected data for 4: yield 85%, mp 334.335 ¡Æ (decomp.).IR (KBr, n/cm.1): 2236 (CN). Found (%): C, 52.19; H, 4.04; N, 2.87, Cl, 13.98. Calc. for C32H28Cl4N2P2Pd2 (%): C, 52.17; H, 3.95; N, 2.77; Cl, 14.03. Selected data for 5: yield 93%, mp 303.305 ¡ÆC (decomp.). 1H NMR (CDCl3) d: 1.78.1.82 (m, 2H, CH2), 1.90.1.94 (m, 2H, CH2), 7.44.7.54 (m, 6H, o-, p-H in Ph), 7.77.7.82 (m, 4H, m-H in Ph). 31P NMR (162.02 MHz, CDCl3) d: 30.5. IR (KBr, n/cm.1): 2238 (CN). Found (%): C, 56.51; H, 4.07; N, 3.98; Cl, 10.33. Calc. for C32H28Cl2N2P2Pd (%): C, 56.55; H, 4.12; N, 4.12; Cl, 10.46. ¢Ò In the case of 4, we failed to record NMR spectra because it is insoluble in conventional solvents such as CH2Cl2, CHCl3, THF, C6H6 and their perdeutero analogues. C Ph2P(O) CN C Ph2P CN HSiCl3 C6H6, reflux 15 h 1 2 Cl Pd Cl Pd Cl Ph2P C CN PPh2 C NC Cl 4 Cl Pd Ph2P PPh2 Cl C C CN CN 1 + PdCl2(PhCN)2 C6H6, 20 ¡ÆC 5 i ii 3 ratio 1:3 = 1:1 (i), 2:1 (ii) C6H6, 20 ¡ÆC .PdCl2Mendeleev Communications Electronic Version, Issue 6, 2001 2 for 5). The chemical shift of 5 is close or even greater than that of starting phosphoryl compound 2 (dP 27 ppm), thus indicating rather strong coordination of the phosphorus atom.According to X-ray diffraction data for 4 and 5,¢Ó¢Ó phosphine 1 acts as a monodentate ligand in both complexes and coordinates palladium with only the phosphorus atom (Figures 1 and 2, both complexes in crystals are lying on the centre of symmetry). In contrast to 5, complex 4 is a rare example14,15 of relatively stable binuclear palladium complexes with two ¥ì-Cl atoms (in CCDC there are only 14 similar structures).It should be noted that the molecular geometries of phosphine ligands in binuclear and mononuclear complexes are different. Namely, Pd(1).P(1), P(1).Ph and P(1).C(1) bond lengths in 4 are shorter than those in 5 by approximately 0.1, 0.003 and 0.02 A, respectively. The trans-effect apparently causes such alterations, and they are consistent with published data.6 In addition to changes in the bond lengths, the mutual orientation of the CN group with respect to the Pd.P bond also depends on the complex type.Thus, CN is in an antiperiplanary conformation in 4, whereas it is in a synclinal conformation in 5. Although it is relatively stable, palladium complex trans-4 with bridging chlorine atoms undergoes a gradual transformation to trans-5.This reaction completed in about two months in a benzene solution (20 ¡ÆC), and was accompanied by the release of PdCl2. The transformation was monitored by 31P NMR spectroscopy. Thus, we found that the nitrogen atom of the cyano group in (1-diphenylphosphino)cyclopropanecarbonitrile 1, as well as in unsubstituted cyanomethyldiphenylphosphine,12 is not involved in coordination with palladium(II).Ligand 1 forms a stable 1:1 complex with bridging chlorine atoms. This work was supported by the Russian Foundation for Basic Research (grant nos. 99-03-33014, 00-15-97386 and 00- 03-32807). We are grateful to Professor O. V. Gussev for his helpful comments. References 1 O. Loiseleur, M. Hayashi, N. Schmees and A.Pfaltz, Synthesis, 1997, 1338. 2 A. Sudo and K. Saigo, J. Org. Chem., 1997, 62, 5508. 3 J. M. Brown, D. I. Hulmes and T. P. Layzell, J. Chem. Soc., Chem. Commun., 1993, 1673. 4 J. M. Valk, G. A.Whitlock, T. P. Layzell and J. M. Brown, Tetrahedron Assymetry, 1998, 6, 2593. 5 C. Pisano, G. Consiglio, A. Sironi and M. Moret, J. Chem. Soc., Chem. Commun., 1991, 421 (and references therein). 6 A. V. George, L. D. Field, E. Y. Malouf, A. E. D. McQueen, S. R. Pike, G. R. Purches, T.W. Hambley, I. E. Buys, A. H.White, D. C. R. Hockless and B. W. Skelton, J. Organomet. Chem., 1997, 538, 101. 7 M. M. Rauhut, I. Hechenbleikner, H. A. Currier, F. C. Schaefer and V. P. Wystrach, J. Am. Chem. Soc., 1959, 81, 1103. 8 K. Cheng and B. M. Foxman, J. Am. Chem. Soc., 1977, 99, 8102. 9 F. A. Cotton, L. M. Daniels, S. C. Haefner and E. N. Walke, Inorg. Chim. Acta, 1996, 247, 105. 10 O. Dahl and F. K. Jensen, Acta Chem. Scand., 1975, B29, 863. 11 P. Braunstein, D. Matt, F. Mathey and D. Thavard, J. Chem. Research (S), 1978, 232. 12 O. Dahl, Acta Chem. Scand., 1976, B30, 799. 13 P. V. Kazakov, I. L. Odinets, A. P. Laretina, T. M. Scherbina, P. V. Petrovskii, L.V. Kovalenko and T. A. Mastryukova, Izv. Akad. Nauk SSSR, Ser. Khim., 1990, 1873 (Bull. Acad. Sci. USSR, Div. Chem. Sci., 1990, 39, 1702). 14 P. J. Dyson, J. W. Steed and P. Suman, CrystEngComm, 1999, 2. 15 F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry, John Wiley & Sons, New York, 1969. 16 J. R. Doyle, P. E. Slade and H. B. Jonassen, Inorg. Synth., 1960, 6, 218.¢Ó¢Ó Crystallographic data for 4 and 5: at 110 K, crystals of 4 are triclinic, space group P1, C32H28Cl4N2P2Pd2¡�2C6H6, a = 10.186(3)A, b = 10.495(3) A, c = 10.679(3) A, a = 76.933(6)¡Æ, b = 79.305(6)¡Æ, g = 76.891(6)¡Æ, V = = 1072.1(5) A3, Z = 1, M = 1013.32, dcalc = 1.570 g cm.3, m(MoK¥á) = = 11.96 cm.1, F(000) = 508; crystals of 5 are monoclinic, space group P21/n, C32H28Cl2N2P2Pd, a = 9.182(3) A, b = 15.008(6) A, c = 11.478(3) A, b = 107.90(1)¡Æ, V = 11505.1(9) A3, Z = 2, M = 1013.32, dcalc = 1.570 g cm.3, m(MoK¥á) = 11.96 cm.1, F(000) = 508.Intensities of 6992 and 5831 reflections for 4 and 5 were measured with a Smart 1000 CCD diffractometer at 110 K [l(MoK¥á) = 0.71072 A, w-scans with a 0.3¡Æ step in w and 30 s per frame exposure, 2q < 52 and 55¡Æ], and 4147 and 3281 independent reflections (Rint = 0.0380 and 0.0285) for 4 and 5, respectively, were used in a further refinement.The absorption correction for both structures was carried out semi-empirically from equivalents. The structures were solved by a direct method and refined by the full-matrix least-squares technique against F2 in the anisotropic.isotropic approximation. Hydrogen atoms were located from the Fourier synthesis and refined in the isotropic approximation in 5 and the riding approximation for 4.The analysis of the Fourier electron density synthesis in 4 revealed that a solvate benzene molecule is disordered by two positions which were refined as the rigid groups with occupancies 0.75 and 0.25. The refinement converged to wR2 = 0.0993 and GOF = 0.902 for all independent reflections [R1 = 0.0490 was calculated against F for 2322 observed reflections with I > 2s(I)] for 4 and to wR2 = 0.1113 and GOF = 1.203 for all independent reflections [R1 = 0.0494 was calculated against F for 2330 observed reflections with I > 2s(I)] for 5.All calculations were performed using the SHELXTL PLUS 5.0 program package on IBM PC AT.Atomic coordinates, bond lengths, bond angles and thermal parameters have been deposited at the Cambridge Crystallographic Data Centre (CCDC). For details, see ¡®Notice to Authors¡�, Mendeleev Commun., Issue 1, 2001. Any request to the CCDC for data should quote the full literature citation and the reference number 1135/101. Figure 1 The general view of 4. Selected bond lengths (A): Pd(1).P(1) 2.229(1), Pd(1).Cl(1) 2.317(1), Pd(1).Cl(2) 2.269(1), Pd(1).Cl(1A) 2.4057(13), P(1).C(5) 1.793(6), P(1).C(11) 1.807(5), P(1).C(1) 1.818(5); selected bond angles (¡Æ): P(1).Pd(1).Cl(1) 94.65(5), P(1).Pd(1).Cl(2) 89.14(5), Cl(1).Pd(1).Cl(2) 176.19(5), P(1).Pd(1).Cl(1A) 176.86(6), Cl(1).Pd(1).Cl(1A) 85.30(5), Cl(2).Pd(1).Cl(1A) 90.93(5), Pd(1).Cl(1).Pd(1A) 94.70(5), C(1).P(1).Pd(1) 113.4(2), C(1).P(1).C(5) 109.0(2), C(1).P(1). C(11) 102.3(2), C(5).P(1).Pd(1) 111.1(1), C(5).P(1).C(11) 107.5(2), C(11). P(1).Pd(1) 113.0(2). C(13) C(14) C(15) C(16) C(11) C(12) C(10) C(9) C(8) C(7) C(6) C(5) P(1) C(1) C(2) C(3) C(4) N(1) Cl(2) Pd(1) Cl(1A) Cl(1) Pd(1A) Cl(2A) P(1A) Figure 2 The general view of 5. Selected bond lengths (A): Pd(1).P(1) 2.321(1), Pd(1).Cl(1) 2.286(1), P(1).C(1) 1.839(4), P(1).C(5) 1.826(4), P(1).C(11) 1.819(4); selected bond angles (¡Æ): P(1).Pd(1).Cl(1) 87.54(4), Cl(1).Pd(1).Cl(1A) 180.00(7), P(1A).Pd(1).P(1) 180.00(6), Cl(1).Pd(1). P(1A) 92.46(4), C(1).P(1).Pd(1) 115.7(1), C(1).P(1).C(5) 103.4(2), C(1). P(1).C(11) 104.0(2), C(5).P(1).Pd(1) 114.2(1), C(5).P(1).C(11) 106.9(2), C(11).P(1).Pd(1) 111.6(1). N(1) C(4) C(3) C(2) C(1) P(1) Cl(1A) Pd(1) Cl(1) P(1A) C(5) C(6) C(7) C(8) C(9) C(10) C(11) C(12) C(13) C(14) C(15) C(16) Cl Pd Cl Pd Cl Ph2P C CN PPh2 C NC Cl 4 Cl Pd Ph2P PPh2 Cl C C CN CN 5 C6H6, 20 ¡ÆC . PdCl2 Received: 24th August 2001; Com. 01/

ISSN:0959-9436     

出版商:RSC    

年代:2001

数据来源: RSC