摘要:

J . CHEM. so(' I)ALTON TRANS. 1989 557 Oxidation of a Pt2(p-S02) Moiety to p-SO, and the Crystal Structure of rpt,(t.-so,)(p-so,)(C,H,,),l t David H. Farrar" and Ravi R . Gukathasan Department of Chemistry, Lash Miller Chemical Laboratories, 80 St. George Street, University of Toronto, Toronto, Ontario, Canada M5S 7A 7 Bis(cyclo-octa-I ,5-diene)platinum(o) as a solid has been found to react immediately with SO, giving [Pt,(p-SO,),(C,H,,),], 0 ) . N.m.r. spectroscopy reveals that the two C,H,, ligands in the dimer ( I ) have three co-ordinated olefinic groups with the remaining one not co-ordinated. The presence of p-SO, ligands is consistent with the i.r. spectrum. Solutions of complex (1) are oxidized slowly by atmospheric 0, to give the novel p-SO, complex [Pt,(p-SO,) (p-SO,) (C,H,,),], (2).Complex (2) was characterized by single-crystal X-ray crystallography and consists of two distorted square-planar platinum(ii) fragments held together by a bridging SO,'- anion and a bridging SO,'-- anion. The bond parameters at both Pt atoms indicate a square-planar co- ordination geometry and a value of 20.1 o is calculated for the dihedral angle between the two square-planar fragments. The p-SO, ligand is o-bonded to both Pt atoms through the S atom while the p-SO, ligand is o-bonded to one Pt atom by the S atom and to the other metal via an 0 atom. The two Pt, the two S, and the 0 atoms form a puckered five-membered ring. The oxidation o f sulphur dioxide to sulphur trioxide is a primary step in the conversation of sulphur to sulphuric acid.' The catalyst currently used to effect this oxidation is supported vanadium pentoxide 2 * 3 although platinum-based catalysts were used in the past.Recently, the sulphur-sulphur dioxide-sulphur trioxideesulphuric acid cycle has attracted attention as a result of more stringent pollution controls.' We report in this paper the room-temperature air oxidation of an SO, ligand bridged between two Pt atoms to a bridging SO, ligand. There are several examples of the oxidation by 0, of an SO, ligand bound to one platinum group metal giving sulphato (SO,'-) complexes.' The first step in this type of reaction is believed to be displacement of the SO, ligand by the 0, ligand, followed by electrophilic attack by an SO, molecule on co-ordinated 0,. Despite the numerous studies on the SO, ligand,4 to our knowledge the air oxidation to SO, has never been reported and this is the first reported complex containing a p-SO, ligand.Results While studying the reactions of platinum cluster complexes and SO, we observed that solid samples of [Pt(C,H,,),] (C,H = cyclo-octa-1,5-diene) react immediately with SO, to give an orange compound, later formulated as [Pt,(p-SO,),- (C,H, ,)J, (1). All attempts to obtain single crystals of (1) for an X-ray crystal structure determination have failed. Complex (1) reacts slowly with 0, to give one product which has been characterized by X-ray crystallography as [Pt2(p-SO3)(!- SO,)(C,H, 2 ) 1 ] , (2). Reaction of (1) and rn-chloroperbenzoic acid also resulted in formation of complex (2), together with some decomposition; (1) does not react with Me,NO to give (2).Crystals of (2) are built up from discrete molecules and a perspective view of the molecule together with the atom numbering scheme is given in the Figure. Selected intra- molecular distances are presented in Table 1. The shortest t CI-Sulphito-S-~-sulphoxylato-OS-bis[(~-cyclo-octa- 1,5-diene)- plat in urn( 11 )] . Suppler?ic~ntut-~ dutu uiuiluhle: see Instructions for Authors, J . Cliem. Sot,.. Dalton T1.uii.s.. 1989, Issue 1, pp. xvii-xx. Table 1. Selected bond distances (a) and angles (") for complex (2) Pt( 1)-S( 1 ) Pt( 1)-S(2) Pt( 1 )-C( 1 ) Pt( 1)-C(2) Pt( 1)-C(5) Pt(l)-C(6) S( 1)-O( 11) S( 1 )-O( 12) S(1)-Pt( 1)-S(2) S(l)-Pt( 1)-C(5) S( I)-Pt( 1)-C(6) S(2)-Pt( I)-C( 1 ) S( 2)-Pt ( 1 )-c (2) Pt( 1)-S( 1)-Pt(2) Pt( 1)-S( 1)-O( 1 1 ) Pt( 1)-S( 1)-O( 12) Pt(2)-S( 1)-O( 1 I ) Pt(2)-S( 1)-O(12) O( 1 1 )-S( 1 )-O( 12) S(2)-0(23)-Pt(2) 2.327(8) 2.290(8) 2.31(8) 2.25(3) 2.29( 3) 2.27(3) 1.45( 2) 1.47(2) 88.7(3) 91.3(8) 92.2(7) 93.6(8) 93.7(8) 109.5( 3) 106.3(8) 107.4(9) 109.3( 9) 109.4(9) 115(1) 115(1) Pt( 2)-S( 1 ) Pt(2)-C(9) Pt(2)-C( 10) Pt(2)-C( 13) Pt(2)-C( 14) Pt( 2)-O( 23) S(2)-0(21) S(2)-O(22) S(2)-O(23) S( 1 )-P t (2)-O( 23 ) S( 1 )-Pt( 2)-C( 9) S( I)-Pt(2)-C( 10) 0(23)-Pt(2)-C( 13) 0(23)-Pt(2)-C( 14) Pt(l)-S(2)-0(21) Pt( 1)-S(2)-0(22) 0(21)-S(2)-0(22) Pt( l)-S(2)-0(23) O(2 1 )-S( 2)-0(23 ) O(22)-S( 2)-O( 23) 2.279( 8) 2.06(2) 2.18( 3) 2.06( 3) 2.29(3) 2.27(3) 1.43(2) 1.43(2) 1.54(2) 9O.0( 5) 94.7( 8) 92.5(9) 90.6(9) 89.3(8) 1 O6.5( 9) 1 14.2( 10) 114(1) 106( 1) 108.1(8) 108(1) contact between the molecules is 2.36 A involving H(61) [bonded to C(6)] and H(101') at (t - .Y, -J,, 1 - :).Complex (2) can be described as two distorted square-planar platinum(I1) fragments held together by a bridging anion and a bridging SO,'- anion. The Pt( 1 ) inner co-ordination sphere contains S(1), S(2), and the cyclo-octa-1,5-diene ligand C atoms C(l), C(2), C(5), and C(6). The olefinic C atoms are sym- metrically displaced about a plane defined by Pt(l), S(I), and S(2). A similar inner co-ordination sphere exists at Pt(2) defined by S( l), 0(23), and C(9), C( lo), C( 13), and C( 14). The angles subtended at both Pt atoms are consistent with a square-planar co-ordination geometry. The S( 1)-Pt( 1)-S(2) angle is 88.7(3)" and S( l)-Pt(2)-0(23) is 90.0(5)".A value of 20.1" was calculated for the dihedral angle between the two square-planar fragments. The two Pt, the two S, and O(23) atoms form a puckered five- membered ring. Atom O(23) is 0.74(2) 8, below a plane defined558 J. CHEM. SOC. DALTON TRANS. 1989 Table 2. N.m.r. spectroscopic data" Complex ' J( 5 P t- ' 3C) 3 4 19 5 pt- 1 3C) c 6( ' 3C) b/ p.p.m. Hz &('HI 'J( ' 95Pt-1 H)/Hz 87.6 (0.63) 96.4 (0.55) 111.0 (0.59) 105.8 (0.59) 110.5 (0.59) 105.7 (0.59) 128.7 (2.8) 93.5 113.2 113.7 114.8 154 187 55 44 45 50 e 228 83 47 60 17 5.43 36 4.98 10 6.86 20 5.71 26 5.5 1 33 5.45 e 5.56 d 105 50 39 d d e " Letters correspond to the positions shown for complex (I). The 'H and 3C resonances have been related by a heteronuclear two-dimensional shift correlation n.m.r.experiment. bThe I3C relaxation times T , , in seconds, are given in parentheses below the chemical shifts. May be 4J('95Pt-Pt-1 'C). Not resolved due to overlap. ' Not observed. Figure. An ORTEP diagram of complex (2) with hydrogen atoms omitted. The thermal ellipsoids are represented by 30% probability contours by Pt( l), Pt(2), S( I), and S(2). All angles subtended at both S atoms are in accord with tetrahedral SO,'^ and SO,'- anions. The p-SO, ligand is o-bonded to both Pt atoms through S(1), while the p-SO, ligand is o-bonded to Pt( 1) by S(2) and to Pt(2) via O(23). The Pt(1)-S(2) and Pt(2)-S(1) distances, 2.290(8) and 2.279(8) A, are not significantly different nor do they differ from the Pt-S values reported for the complex [Pt,(p-SO,),- (PPh3),] of 2.271(5), 2.279(4), and 2.275(4) A.The Pt(1)-S(1) distance, 2.327(8) A, does differ significantly from the other values; the reason for this difference is not clear. The S-0 distances in the p-SO, ligand are normal.6 The exo-S-0 distances in the p-SO, ligand are both 1.43(2) A which also is the value reported for the SO, m~lecule.~ The S(2)-O(23) distance, 1.54(2) A, is longer than the two exo distances although it is shorter than a S-0 single bond length of 1.70 A, calculated using covalent radii.' The Pt-C distances for the olefinic C atoms trans to a S atom are equivalent [average 2.28(2) A] while the two C atoms trans to O(23) have an average Pt-C distance of 2.12(8) A. This is consistent with the relative truns influence of oxygen uersus sulphur ligands.' All parameters associated with the C,H, 2 fragments are normal.' O n.m.r.spectrum of complex (2) at 25 "C contains only four resonances in the olefinic region and thus a fluxional process The 0 0 must exist which equates the carbon atoms in each of the four olefin groups. Of the four values, presented in Table 2, one is decidedly upfield of the remaining three and exhibits a much larger 95Pt-1 coupling constant. This resonance is assigned to the carbon atoms labelled C(9) and C( 10) which are trans to oxygen and more strongly bound to platinum. Complex (1) is assigned the structure shown on the basis of spectroscopic and analytical data. While this structure is usual, it does fit all the data we have been able to obtain. Elemental analysis gives the empirical formula Pt(SO,)(CEHl 2).The i.r. spectrum of (1) has v(S0,) bands at 1 177, 1 043, and 997 cm-' suggesting the presence of a p-SO, ligand and possibly an q2,p- SO, ligand.' ' The ' 3C n.m.r. spectrum of complex (1) has seven resonances due to olefinic carbon atoms and the assignment of these peaks is indicated in Table 2. The observation of '95Pt-Pt-'3C inner satellites confirms the dimeric nature of the complex. As in the case of (2), the upfield signals with large 'J(195Pt-13C) values are ascribed to the carbon atoms which are truns to an oxygen atom. The remaining two olefinic carbon atoms in the C,H12 ligand have been identified by two-dimensional n.m.r. experi- ments. ' A heteronuclear two-dimensional shift correlation spectrum of the ' H and 13C resonances has allowed us to correlate the 'H and I3C data as presented in Table 2.It was then shown, using 'H-' 9sPt heteronuclear two-dimensional shift correlation, that the 'H signals from the H atoms bonded to the C atoms labelled a-d are coupled to the same Pt atom. Resonances c-f are assumed to be trans to S atoms based on the similarity with the chemical shifts observed for complex (2).J . CHEM. SOC. DALTON TRANS. 1989 559 The remaining signal at 128.7 p.p.m. is very close to the position observed for the olefinic groups in the cyclo-octa-1,5-diene molecule. The peak integrates as two C atoms and we have assigned this resonance to an unco-ordinated olefin in a C8H1 , ligand. The possibility that this signal could arise from free cyclo-octa- 1.5-diene has been eliminated as the relaxation time T I for peak (g, h) is 2.8 s whereas the corresponding value for cyclo-octa-1,5-diene was found to be 15 s.The solid-state 13C n.m.r. spectrum of complex (1) has broad unresolved peaks at approximately the same chemical shifts as those found in the solution spectrum and thus no major change occurs when samples of ( 1 ) are dissolved. In the absence of magic angle spinning the entire spectrum collapses which again suggests that the peak labelled (g, h) is related to a 'dangling' cyclo-octa-1,5- diene ligand and not an occluded molecule. Discussion Solid samples of Pt(C,H, ,), react immediately with so, giving [Pt,(p-S02),(C8Hl ,),I, (1). N.m.r. spectroscopy was used to determine the bonding modes of the C8H12 ligands. The presence of a p-SO, ligand is consistent with the i.r.spectrum although it is not entirely clear whether the second SO, ligand is q2-S0 bound to one metal atom and 0-0 bound to the other (as shown) or a 0-S:o-O bridge with an e m S=O. There is one example in the literature of the former l 1 whereas the latter has not been observed. Solutions of complex (1) are oxidized slowly by atmospheric 0, to give the novel p-SO, complex [Pt2(p- S03)(p-S0,)(C,H12)2], (2). Hydrogen is not evolved in the air oxidation and solutions of (1) are found to convert cleanly into (2) under an atmosphere of dry oxygen, thus precluding reaction with H,O or an HO radical initiated oxidation of S0,.13 Bridging SO2 ligands are usually quite stable chemically 4314 and thus the reasons as to why a p-SO, ligand in (1) is easily oxidized are of interest.The oxidation of SO, ligands to SO, in mononuclear complexes is known.14" There IS one example of the complete oxidation of the p-SO, ligand in [(Fe(SMe)- (CO),( PMe,)) ,SO2] giving [Fe(SMe)(CO),(PMe3)]zCS0,1." Air oxidation where only one 0 atom is transferred has been reported for the v2-S2 ligand in [Mn(C,H,)(CO),(S2)] result- ing in [Mn(C5H5)(CO),(S,0)]." To our knowledge, this is the first observation of the oxidation of a p-SO, ligand to a p-SO, ligand. While the exact nature of the p-SO, ligand in complex (1) prior to reaction with 0, is not known, if our assignment as v - S 0 bound to one metal atom and 0-0 bound to the other is correct, then molecular models indicate some ring strain is present. The observation of six separate resonances for co- ordinated olefinic C atoms in the 13C n.m.r.spectrum of (1) at room temperature shows that the complex is fairly rigid and does not possess a mirror plane. This is in contrast to complex (2) where at the same temperature fluxionality associated with inverting the five-membered ring results in the C8H12 ligands having pseudo-mirror symmetry. One possibility is that release of strain energy is partly responsible for the facile nature of the reaction. The oxidation is formally changing a trigonal planar platinum(o) centre in (1) to a square-planar platinum(1r) centre in (2) with co-ordination of the 'dangling' olefin, assuming that our structural assignment of (1) is correct. The complex [{ Mo(CO),(PPh,)(py)(p-SO,)),I(py = pyridine) has two p- SO2 ligands co-ordinated to one metal through a S=O TC. bond and a second metal via the remaining 0 atom forming a six- membered ring, and the complex is very stable.' ' Normal '(0-S)-p-SO,' ligands do not undergo further oxidation when treated with an excess of rn-chloroperbenzoic The reaction of the p-SO, ligand in the complex [Pt,(p-S0,)(C0)2(PBut2Ph)2] with Me,NO results in removal of the SO, ligand as Me,NO-S02.'9 In contrast, complex (1) does not react with Me,NO. Experimental Infrared spectra were recorded on a Nicolet 5DX FTIR spectrometer, 'H, 13C, and 195Pt n.m.r. spectra in CDC1, on a Varian XL 400 spectrometer operating at 400, 100.6, and 85.6 MHz, respectively. The ' H and 13C chemical shifts were measured relative to an internal solvent reference and are reported relative to tetramethylsilane as standard, while the 195Pt chemical shifts are referenced to K,[PtCI,].Solid-state I3C magic angle spinning n.m.r. spectra were kindly recorded by Professor C. A. Fyfe." The complex [Pt(C,H,,),] was synthesized by literature methods.,' Solvents were rigorously dried and all manipulations were performed under a prepurified nitrogen atmosphere unless otherwise stated. Microanalyses were by Analytische Laboratorien, West Germany. Sjwthesis (Ilf'[ Pt,(p-S02)2(C,H ,),I, (1).-A solid sample of [Pt(C,H,,),] (0.30 g, 0.729 mmol) was exposed to an atmo- sphere of SO, resulting in an immediate colour change to a dark purple solid. The free C,H12 was removed by washing with hexanes.This solid was then dissolved in CHCI,. an insoluble fraction was removed by filtration, and the orange product was obtained by precipitation with hexanes, filtered off, and dried at reduced pressure. Yield 83%. 1.r. (Nujol mull) v(S-0) 1 177m, 1 043s, and 997m (sh) cm-' (Found: C, 26.0; H, 3.2; 0, 8.6; S, 8.6. Calc. for C,,H,,O,Pt,S,: C, 26.1; H, 3.3; 0, 8.7; S. 8.7";)). Sjwthesis of [Pt2(p-S03)(p-S0,)(C8H 12)2], (2). Complex (1) (0.25 g, 0.34 mmol) was dissolved in CHCI, (25 cm3) and the solution was stirred under an oxygen atmosphere for 48 h at 23 "C. The solvent was removed at reduced pressure and the resulting yellow solid was recrystallized from CH,CI, -hexanes mixtures. Yield 952). 1.r. (Nujol mull) v(S-0) 1 214s, 1 154s, 1086s, 1020s, 998m, 847s, and 652s cm-'.Crystallography.- Crystal data f b r (2). Cl,H2,05Pt,S2, M = 750.67, orthorhombic, a = 12.1 17(2), b = 24.158(4), c = 12.126(1) A, U = 3 549.8 A3 (by least-squares refinement on diffractometer angles for 25 automatically centred reflections, h = 0.710 69 A), space group Pbca,,, Z = 8, D, = 2.8 1 g ~ m - ~ , yellow plates, crystal dimensions 0.012 x 0.011 x 0.005 cm, crystal faces { l l l ) , {loo), p(Mo-K,) = 161.6 cm-'. F(000) = 3 104. Data collection and processing. Enraf-Nonius CAD4 dif- fractometer, graphite-monochromated Mo-K, radiation. 0-20 mode with scan width 0.80 + 0.35 tan 0, scan speed 0.5-10.0" min-'. 3 118 Unique reflections measured (1 < 20 < 50". + 17, + k , +/). Gaussian absorption correction23 with a 12 x 10 x 6 grid (transmission coefficients varied from 0.285 to 0.406); no decomposition observed; the recorded intensities were corrected for Lorentz and polarization effects.23 1 225 Unique data with Z > 3 4 1 ) .All calculations were performed using the Enraf-Nonius Structure Determination Package running on a DEC PDP- 1 1 /23 computer. Structure anulysis and rejinement. The positional co-ordinates for the Pt atoms were obtained from a three-dimensional Patterson synthesis. A series of difference Fourier syntheses and least-squares refinements revealed the positions of the remaining 31 non-hydrogen atoms. Hydrogen atoms were located and included in subsequent calculations with idealized positional co-ordinates (either sp2 or sp3 geometries and a C-H bond distance of 1.0 A) but not refined.After several cycles of full- matrix least-squares refinement on F the model converged at R = CllFJ - ~ F o ~ / C ~ F o ~ ~ = 0.0474 and R' = [Xnl(lF,I - lFol)2/ Xct*Fo23' = 0.0510 (1 225 observations and 146 variables; Pt, S, and 0 atoms refined with anisotropic thermal parameters and all C atoms refined isotropically). In the final cycle no shift exceeded 0.02 of its standard deviation. A total difference Fourier synthesis calculated from the final structure factors5 60 J. CHEM. SOC. DALTON TRANS. 1989 Table 3. Positional parameters for the non-H atoms of complex (2) Atom X Y 0.093 43(9) 0.330 19(9) 0.206 3(7) 0.178 8(7) 0.265(2) 0. I35(2) 0.1 30( 2) 0.178(2) 0.301(1) 0.023(3) - 0.049( 2) - 0.1 52( 3) - 0.142(3) - 0.030( 2) 0.043 2) 0.023(3) 0.0 I 7( 3) 0.337(3) 0.4 1 0( 3) O.S29( 3) O.S66( 3) 0.492( 3) 0.403 3) 0.380( 3) 0.373(3) 0.139 38(4) 0.1 19 07(4) 0.074 6( 3) 0.207 2(3) 0.046 l(7) 0.039 l(8) 0.206 3(8) 0.260 4( 8) 0.191 7(8) 0.201(1) 0.194(1) 0.I 63( 2 ) 0.100( 1 ) 0.072( 1 ) 0.079( 1 ) 0.1 1 ] ( I ) 0.17 l(2) 0.053( I ) 0.047( I ) 0.053( 1 ) 0.105( 1 ) 0. I54( I ) 0.169( 1 ) 0.139( I ) 0.077( 1 ) 0.596 7( 1 ) 0.400 1( I ) 0.510 4(6) 0.496 l(7) 0.598(2) 0.442(2) 0.389( 2 ) 0.547(2) 0.484( 2) 0.723 3) 0.643 2) 0.650(3) 0.645(3) 0.645(2) 0.731(2) O.838( 3) 0.830( 3) 0.277( 3) 0.361 (2) 0.3S9( 3) 0.315(3) 0.33 l(3) 0.260( 2 ) 0. I53( 2) 0. I64( 2) Estimated standard deviations in the least significant figure(s) are given in parentheses. contained no features of chemical significance with the highest peak, of electron density 1.65 e k3, between atoms O(22) and W( 13) at fractional co-ordinates (0.144, 0.322, 0.603).The error in an observation of unit weight is 1.1 1. Final positional parameters for the non-H atoms are given in Table 3. Additional material available from the Cambridge Crystal- lographic Data Centre comprises H-atom co-ordinates, thermal parameters, and remaining bond lengths and angles. Recrctioi~ of Conip1e.u (1 1 mu’ m-Clilor.opt.rht.riioic. A c i d - Complex ( I ) (0.30 g, 0.04 mmol) and m-chloroperbenzoic acid (0.01 g, 0.06 mmol) were stirred in CH,CI, (20 cm3) for 24 h at 23 “C. The solvent was removed at reduced pressure and an ‘H n.m.r. spectrum of the brown residue, dissolved in CDCI,, indicated that conversion into complex (2) had occurred, together with some decomposition.Acknowledgements We thank the Natural Sciences and Engineering Council of Canada for operating and equipment grants. We also thank Dr. D. Hughes for his technical assistance in acquiring the n.m.r. spectra. References I C. N. Kenney, Crrtcr!i:yis (Lonc/m). 1980, 3, 123. 2 A. Urbanek and M. Trela, Ccrtul. Rer.-Sci. Eng., 1980, 21, 73. 3 T. J. P. Pearce, ed. G. Nickless, in ‘Inorganic Sulphur Chemistry,’ 4 W. A. Schenk, Atigen.. CIwni.. I t i t . Ed. Etigl., 1987, 26, 98 and refs. 5 C. S. Browning. D. H. Farrar, R. R. Gukathasan, and S. A. Morris, 6 D. C. Moody and R. R. Ryan, Itiorg. C’Ii~ni., 1977, 16, 1052. 7 K. J. Palmer, J. Ani. Ckeni. Soc., 1938, 60, 2360. 8 L. C. Pauling, ‘The Nature of the Chemical Bond,’ Cornell 9 T. G. Appleton, H. C. Clark. and L. E. Manzer, Coord. Chem. Rec., 10 C . Couture and D. H. Farrar, J. Ch~ni. Soc., Dcrltoti Truns., 1986, Elsevier, New York, 1968, pp. 535-560. therein. Orgcinot?ic rullics, I 9 8 5 , 4, I 7 SO. University Press, Ithaca, New York, 1960. 1973, 10, 335. 1 1 12 13 14 15 16 17 18 19 20 21 22 23 1395. G. D. Jarvinen, G . J. Kubas, and R. R. Ryan, J. Chrni. Soc., Cizen7. Coniniuti., 198 I , 305. G. A. Morris, Mugn. Rcson. Clieni., 1986, 24, 371. H. Niki, P. D. Maker, C. M. Savage, and L. P. Breltenback, J . P h j x Cliem., 1980, 84. 14. R. R. Ryan, G. J. Kubas. D. C. Moody, and P. G. Eller, Strircf. Bonding (Bditi). 1981, 46, 47: D. M. P. Mingos, Trnnsition Met. Chet?i. ( Weinhein7. Ger.), 1978. 3, 1. D. C. Moody and R. R. Ryan, Inorg. Chcni., 1977, 16, 1052. M. S. Arabi, R. Mathieu. and R. Poilblanc, Inorg. Chim. Actu, 1979. 34, L207. M. Herberhold, B. Schmidkonz, M. L. Ziegler. and T. Zahn, Anpr.. Cher~., I n t . Ed. EngI., 1985, 24, 5 15. J. E. Hoots. D. A. Lesch, and T. B. Rauchfuss, Inurg. CIi~n7., 1984, 23, 3 1 30. C. S. Browning and D. H. Farrar, unpublished work. C. A. Fyfe, ‘Solid Sfatc NMR,fOr Chet?ii.st.s,’ CFC, Guelph, Ontario, 1983. J. L. Spencer. Inorg. Sytitli., 1979, 19, 2 13. ‘International Tables for X-Ray Crystallography,’ Kynoch Press, Birmingham, 1969, vol. 1. CAD4F and SDP-PLUS User’s Manuals, Enraf-Nonius, Delft, 1982. Receioed 29th April 1988; Paper Sj01685B

ISSN:1477-9226    

DOI:10.1039/DT9890000557

出版商:RSC    

年代:1989

数据来源: RSC