摘要:

J . CHEM. SOC. DALTON TRANS. 1992 345Copper and Nickel Complexes of 1.8-Disubstituted Derivativesof I ,4,8,1 I -Tetraazacyclotetradecane tJames Chapman,a George Ferguson,b John F. Gallagher,6 Michael C. Jenningsb andDavid Parker * r aa Department of Chemistry, University of Durham, South Road, Durham DHl 3LE, UKDepartment of Chemistry, University of Guelph, Guelph, Ontario N I G 2W7, CanadaThe stereoselective synthesis of various 1,8-disubstituted derivatives of 1,4,8,11 -tetraazacyclotetradecane(cyclam) has been achieved and copper and nickel complexes prepared. For the 1,8-dibutyl derivative, thesquare-planar nickel( 11) com'plex exists as two diastereoisomers, as revealed by crystallographic analysis.The structure of the copper(l1) complex of this ligand confirmed that a strong in-plane ligand field wasconserved in square-planar complexes notwithstanding the dialkylation at nitrogen.The structures of thecopper(i1) complexes of two 1,8-dicarboxymethyI derivatives of cyclam also reveal primary N, co-ordination with carboxyl oxygens occupying the elongated axial sites. The tricyclic ligand 1,5,8,12-tetraazatricyclo[l 0.2.2.25,8]octadecane is readily prepared from one of these diacids and the coppercomplex is kinetically stable in solution with respect to attack by hydrogen sulfide and to acid-catalyseddissociation.The elaboration of the co-ordination chemistry of 1,4,8,11-tetraazacyclotetradecane (cyclam) has been a pivotal feature inthe development of macrocyclic complexation chemistry. Lesswork has been reported for monosubstituted derivatives ofcyclam,2 although the chemistry of both C- and N-substitutedderivatives has been described in some detai1.3*4 Much lessattention has been paid to the chemistry of disubstitutedderivatives although they are intrinsically very interesting.For example the regioselective formation of 178-disubstitutedderivative^,^.^ A, in which the substituent may act as a donor toa metal allows the formation of octahedral complexes in whichthe two additional neutral or anionic donors X may adopt axialbinding sites, B (X = C02H, CONR,, C 0 , - or PMe02-).InA R = alkyl or carboxyalkyl Bsuch a complex destabilising steric interactions between the N-substituents and other ligand atoms or torsional ring-straineffects are likely to be minimised, and a small divalent ion suchas Cu2 or Ni2 + may still experience a strong ligand field fromthe four 'equatorial' ring nitrogens, comparable to that found inrelated complexes of cyclam itself.Such a situation may becompared with that found in the nickel(r1) complex of 1,4,8,11-tetramethyl- 1,4,8,11 -tetraazacyclotetradecane, where the lowligand-field strength observed has been attributed to astretching of all the Ni-N bonds to relatively long values (1.98-1.99 A) "1 due to van der Waals repulsions between N-methylgroups and proximate hydrogens. If the donor X in B is ionis-able, then metal complexes with divalent ions will be chargeneutral overall. Such complexes are likely to be somewhatlipophilic and this lipophilicity may be enhanced by alkylationof the 4,ll positions.There are additional reasons for studyinglipophilic metal complexes. For example, kinetically stablecomplexes of 64Cu (p+, t+ = 12.8 h) are required for in uivo usein diagnostic medicine. Positron-emission tomography affordshigh-resolution detection of the tracer isotope in viuo," andlipophilic complexes may exhibit tissue specificity in theirbiodistribution. A particularly attractive target is the brain, inwhich the problem of localisation is directly related to theability of the complex to cross the blood-brain barrier. Lowmolecular weight ( d 600), charge-neutral and relatively lipo-philic complexes may transverse the membrane.' A secondpotential application of lipophilic metal complexes is inagrochemistry.The depletion of trace-metal cations in soilsand plants is usually rectified by application of large quantitiesof their hydrophilic edta or dtpa complexes (H4edta =ethylenediaminetetraacetic acid, H,dtpa = diethylenetri-amine-N,N,N',N",N"-pentaacetic acid). It is possible that themore lipophilic complexes of these essential cations, e.g. Mn2 +,Cu2+ or Zn2+, may be much more readily taken up by plantroots thereby reducing the dosage required.There have been only isolated reports of the stereoselectiveN-functionalisation of cyclam (L'). For example, in the carb-oxymethylation of L2, steric inhibition of eiectrophilic attack atthe 4,11 positions leads to selective 1,8 functionalisation givingL3.12 When functionalising cyclam itself, it has been found thatditosylation occurs with selective formation of the 1,8-ditosyl-amide, L4.,q6 This compound has been used as the precursor forthe formation of a series of 178-dialkylated derivatives L5-L7and the structures of the nickel and copper complexes of L5 arereported herein, together with the structures of the copper(r1)complexes of H2L8 and H2L9 in each of which the primary co-ordination to copper involves the four ring nitrogen atoms withthe oxygens of the carboxylates occupying the elongated axialsites. A preliminary account of part of this work has a ~ p e a r e d .~t S ~ p p l ~ ~ t ~ ~ ~ ~ t i t c r r ~ ~ tiutu ur:uiluhle: see Instructions for Authors, J. Chem.Soc., Dulton Trum., 1992, Issue I , pp.xx-xxv.These bond lengths may be compared with Ni-N bond lengths of1.926 and 1.940(4) A foundsb in the structure of 5,12-dimethyl-1,4,8,1 I -tetraazacyclotetradecane L ".Results and DiscussionLigand Syntheses.-Alkylation of the ditosylamide L4 (Bul,MeCN, Na,CO,) afforded the dibutyl compound L'O inmoderate yield. Selective monoalkylation of L4 occurred usin346 J. CHEM. SOC. DALTON TRANS. 1992L4H2L8 R = HH2Lg R = MenO U(:ToUHL'"bromobutane instead ofL ~ R = HH2L3 R = CkC02HnISNUi" :jLI6 L"iodobutane under similar reactionconditions to give L12. This was N-methylated under standardEschweiler-Clarke conditions to yield L' '. Direct methylationof L4 (HC02H, HCHO) afforded the dimethyl derivative L1',completing the short series.Detosylation of L'O, L" and LI3was effected smoothly and efficiently in excellent yield usingHBr-MeC0,H in the presence of phenol giving the tetraminesL5, L6 and L7 which were isolated as their hydrobromide salts.The synthesis of the diacid H2L8 and of the bicyclic lactamL14 (derived from H,L8) was effected as reported earlier.6Although H2L8 lactamises at room temperature in aqueoussolution (even in 6 mol dm-3 HCI!) it may be methylated in goodyield (HCHO, HC02H, 74%) giving L9. Reduction of thelactam LI4 [BH3-tetrahydrofuran (thf), 60x1 permitted thesynthesis of the tricyclic tetramine L". This ligand, a cryptand,may also be regarded as a 'structurally reinforced' macrocycle I 3in which the rigidity of the tricyclic system enforces the metalTable 1complexesVisible absorption spectra (H'O, 293 K) for nickel and copperComplex cation[Ni L']' +[NiL6]'+[NiL'] ' +[NIL' '1' +[NiL']'+[ ~ i ~ l 8 ] 2 + d.e[CUL'8]2+ J[CUL']' + f[ c u L 1 53 2 +[CUL']2 +[CUL6]2 +[CUL']2 +Laxlcm- '21 69121 14121 92921 82022 22222 47323 54018 31019 90018 58718 93918 31518 65610 4, a19711922'19931984202020432140' 10 D = vd4/I 1.0 (ref.15). frans Isomer. ' cis Isomer. Ref. 16.L18 ~1,4,7,10-tetraazacyclotridecane. Ref. 7.ion to bind in the plane of the donor atoms. In binding in such amanner, each of the piperazine rings needs to adopt a boatconformation which is energetically unfavourable and will con-tribute an unfavourable term to the enthalpy of metal complex-ation. The unfavourable nature of the chair-boat intercon-version and the structural rigidity of the ligand as a wholeare reflected in the observed protonation constants for LlS.Potentiometric titrations reveal successive pK, values of 8.33(3)and 3.02(2).The first of these values is very similar to that foundfor other piperazines or 1,4-diazabi~yclooctane,'~ but thesecond protonation constant is rather low. The relatively highacidity of the diprotonated species H2L1' 2 + may be related tosteric inhibition of protonation of the monoprotonated ligand.The 'H NMR spectrum of the ligand was examined as afunction of pH. At both high pH (2 11) and in CDC13 orCD2CI,, resonances were observed that were consistent withtime-averaged D,, symmetry: a single quintet and triplet for thetwo NCH,CH,CH,N moieties and a pair of symmetricalmultiplets for the piperazine ring protons.The spectrum of thetetracation was shifted to higher frequency (in 12 mol dm-'DCI-D,O) but also had the same features (e.g. quintet forNCH2CH2CH2N) suggesting that this species has similar highsymmetry. At intermediate values of pH, broadened resonanceswere additionally observed and the spectra obtained were morecomplex. In a deuterioacetate buffer at pH 5, two multiplets in1 : 1 ratio for the NCH2CH2CH2N resonances were observedsuggesting the structure shown for the monocation HLI5+,while at pH 0 the broadened resonances of the protons in thesix-membered rings had shifted to higher frequency and at leastfour resonances for the NCH2CH2CH,N protons were dis-tinguished.Certainly the protonation behaviour of L' is quitedifferent from that of 1,4,8,1 l-tetramethyl-1,4,8,1l-tetraaza-cyclotetradecane, and it is not behaving like two independentpiperazines.Metal Comple.ws.-Nickel- and copper-(11) complexes ofligands L5-L7 were prepared and the structures of the 1,s-dibutyl derivatives [NiL5]' + and [CuL5I2+ determined by X-ray crystallography. In all of the nickel complexes, the positionof the observed visible absorption band (Table 1 ) suggestedthat the nickel was square planar with a relatively strong ligandfield. This was confirmed by the crystallographic analysis of[NiLS][C104], in which the Ni-N bond lengths were 1.939(2)(to NH) and 1.970(2) A (to NBu) (Table 2).In this centro-symmetric structure (Fig. l ) , the perchlorate counter ions werefairly remote from the nickel [0( 1) Ni 3.072(8) A], and weredisordered over two sites. The ring adopted the expectedquadrangular [3434] conformation with an RSSR configurationat the nitrogen stereogenic centres. For comparison, in thenickel complex of 5,7,12,14-tetramethyl-l,4,8,11 -tetraazacycloJ . CHEM. SOC. DALTON TRANS. 1992 347Fig. 1 Structure of [NiLS][CIO,], in the crystal. The perchlorate anions were disordered over two sites with equal occupancyTable 2 Selected molecular dimensions (distances in A, angles in ")for [NiLS][C10J2 with estimated standard deviations (e.s.d.s) inparenthesesNi-N( 1 ) 1.970(2) N( 1)-Ni-N(4) 87.45(9)Ni-N( 4) 1.939(2) Ni-N( 1 )-C( 2) 105.1(2)O( 1 ) - -.Ni 3.072(8) Ni-N( 1 )-C( 7') 1 15.8(2)N(4) * - * O( 3") 3.150(9) Ni-O( 1 )-C1 1 52.0( 3)H(4) * * * O(3") 2.37 N(4)-H(4)-0(8") 146.5Symmetry operations: I -s, -j: - z ; I1 s, J; - 1 + 2.N(4) * - O(8") 2.997( 13) N(4)-H(4)-0(3") 139.4H(4) * * * O(8") 2.16tetradecane, L',, nickel-nitrogen bond lengths of 1.964(3)and 1.974( 3) A were found *' in the square-planar complex withthe perchlorate counter ion somewhat closer at 2.808(5) 8, fromnickel. In the related nickel(i1) complex of L17, Ni-NH bondlengths were 1.926 and 1.940 A.8 Crystallisation of the nickelcomplex of L5 from aqueous solution gave prisms (A,,, 461nm) initially and plates on further concentration and slowevaporation of the aqueous solution (Amax 473 nm).The formercomplex was determined to be the trans isomer (Fig. l), and itwas assumed that the other complex was a diastereoisomer withthe N-butyl groups cis related in the complex. Crystallographicanalysis (both at 293 and 173 K) of these plates revealed severedisorder in the crystal lattice. There were two independentcations in the unit cell each lying across mirror planes. In eachcase the nickel atom and the two secondary nitrogens lie on thesame mirror plane. This demands that the N-Bu groups are cisdisposed. Electron-density maps revealed the nickel, nitrogenand the first two carbon atoms of the butyl chain but as aconsequence of the mirror-imposed disorder the five- and six-membered chelate rings could not be distinguished and acomposite was observed with ill defined density correspondingto a superposition of the five- and six-membered rings.Inaddition, all of the four perchlorate groups in the unit cell (eachlying on a mirror plane) were disordered. The analysis iscertainly sufficient to pinpoint the differences from the structureof the isomeric complex. It is very likely that the plates areindeed a cis diastereoisomer with an RSRS configuration atnitrogen. Although the formation of two isomeric copper-cyclam cationic complexes has been known for some time, theobservation and structural determination of two diastereo-isomeric square-planar nickel(I1) complexes of a tetraazamacrocycle appears to be most uncommon.The copper(l1) complex of L5 was isolated as its hexa-fluorophosphate salt (from MeCN-MeOH-Pr',O) and crystal-lised in the same space group as [NiL5][C10,]2. Again the 14-membered ring adopted a [3434] quadrangular conformationwith an RSSR configuration at each nitrogen (Fig.2) and thetwo PF, counter ions occupied the axial sites. The neares348 J. CHEM. SOC. DALTON TRANS. 1992Fig. 2 Structure of [ C U L ~ ] [ P F ~ ] ~ in the crystalTable 3[CUL'][PF~]~ with e.s.d.s in parenthesesSelected molecular dimensions (distances in A, angles in ") forCu-N( 1) 2.062(2) N( 1 )-Cu-N(4) 86.61(8)Cu-N(4) 2.005(2) Cu-F( 1 )-P 158.48(9)F( 1) - * CU 2.840(2) N(4)-H(4)-F( 1') 1 17.5N(4) * * F( 1") 3.303(4) N(4)-H(4)-F(4I1) 147.5H(4) - * F( I") 2.76N(4) * F(4") 3.22 l(4)H(4) * F(4") 2.38Symmetry operations: I --9, -y, - z; I1 x, y, - 2.Table 4[Cu( H 2L9)] [ClO,] ,.2H *O; with e.s.d.s in parenthesesSelected molecular dimensions (distances in A, angles in ") forCu-N( 1 ) 2.070(3) N( l)-Cu-N(4) 8 7 4 1)Cu-N(4) 2.096(3) N( 1 *)-Cu-N(4) 92.9( I )CU-O( 10) 2.369( 3) N( I)-Cu-O( 10) 101.8( 1 )N(l*)-Cu-O(1O) 78.2(1)N(4)-Cu-O( 10) 91.9(1)Cu F distance was 2.840(2) 8, (Table 3).The Cu-N bondlengths of 2.005(2) (to NH), and 2.062(2) 8, are quite short, andmay be compared to values of 2.03 8, for a 'strain-free' Cu-NHbond ' and 2.02 8, observed in the copper complex of cyclam.The structural analyses of these nickel and copper complexes ofL5 together with the observed ligand-field strength (Table 1)certainly support the premise that 1,8-disubstitution of 1,4,8,11-tetraazacyclotetradecane does not compromise complexstability as a result of unfavourable steric interactions.Indeedthe only obvious poor non-bonding interactions in thestructures of the copper and nickel complexes are apparent inthe six-membered chelate rings. There are unfavourable 1,3-synaxial interactions between the NBu group and an NH ineach chair (Figs. 1 and 2).With the rrans-diacetate ligands L8 and L9, the carboxy-methyl groups are able to bind to the metal ion in axial siteswhile retaining a strong ligand field in the plane of the ring. Thisview was confirmed by the position of the d 4 absorption(h,,, 565 and 573 nm respectively) and in the crystallographicanalyses of the neutral copper(i1) complexes, which crystallisedfrom aqueous acidic solution. With the dimethyl ligand H,L9,the crystal structure (Fig.3 ) revealed the copper to be six-co-ordinate with four short bonds to nitrogen [2.070(3) and2.096(3) A] and two longer bonds to oxygen [Cu-0 2.369(3)8,] with the copper at an inversion centre (Table 4). In thecrystal lattice, a hydrated proton was hydrogen-bonded to eachcarbonyl oxygen and to a proximate perchlorate counter ion.The protonation of the complex on oxygen may account for theslight elongation of the Cu-0 bonds, notwithstanding theJahn-Teller distortion and the strong in-plane ligand field.Support for this idea comes from a comparison of the relatedstructure of [CuL8] (Fig.4), in which the Cu-0 distance isshorter, 2.263(4) 8, (Table 5), and the Cu-N bond lengthsare similar, 2.095(3) (to NCH2C02) and 2.014(4) A, to thesecondary nitrogens. The shorter Cu-NH bond in [CuL'] com-pared to the Cu-NMe bond in [CuL'] is expected. NumerouJ. CHEM. SOC. DALTON TRANS. 1992 349nO(11P "Fig. 3the pattern of hydrogen bondingStructure of [Cu(H,LY)][CI0,],~2H,0 in the crystal showingTable 5[CUL~][C~O,],.H,L'~ with e.s.d.s in parenthesesSelected molecular dimensions (distances in A, angles in ") forCu-N( 1 A)Cu-N(4A)CU-O( IOA)N(4A)-0( 1 )HN(4A)-O( 1)HN(IB)-O(l1A)N( I B)-O( 1 1 A)N( 4B)-C(9B)N(4B)-C( 5B)C(9B)-0( IOB)N( 1 B)-C(2B)C(3B)-N(4B)2.095(3)2.01 4(4)2.263(3)3.046(9)2.2 11.762.676(4)1.34 l(7)1.47 l(5)1.2 16(5)I .489(7)1.456(5)N( lA)-Cu-N(4A)N( 1 A)-Cu-N(4A)N( 1 A)-Cu-O( 1 OA)N(4A)-Cu-O( IOA)C(2B)-N( 1 B)-C(7B*)C(2B)-N( 1 B)-C(SB)N( 1 B)-C(2B)-C(3B)C( 2B)-C( 3B)-N(4B)C(3B)-N(4B)-C( 5B)C( 3B)-N(4B)-C(9B)N(4B)-C(9B)-O( 10B)86.3( 1)93.7( 1)79.7( 1 )90.0( 1)11 1.2(4)106.5(4)11 1.6(3)1 13.3( 5)1 17.0(4)124.2(4)123.7(4)studies have demonstrated that metal-nitrogen bond lengthsare increased by N-alkyl substitution 7 * 1 9 due to van der Waalsrepulsions between alkyl hydrogens and those elsewhere in thecomplex.For example in the bis(N,N-diethylethy1enediamine)-copper(1r) complex, values of 2.08 and 2.02 A were found forcopper tertiary- and secondary-nitrogen bonds, respectively.'In each of the copper(i1) complexes of L8 and L9, the macro-cyclic ring adopts a [3434] conformation with the configurationat each nitrogen centre being RRSS. In the case of [CuL'], thecomplex crystallised with the diprotonated lactam H2LI4 in thecrystal lattice. I n the unit cell, the lactam lay in the centre (at aninversion centre) with the copper complex at the four corners.The carbonyl oxygens of the copper complex were hydrogen-bonded to the protonated tertiary amines of the lactam and theFig. 4bonding to the perchlorate anions of the protonated lactam H2L14,+Structure of [CuL'] in the crystal showing the hydrogensecondary N-H groups were hydrogen- bonded to perchloratecounter ions (Fig. 5).These copper complex structures with ligands L8 and L9 maybe contrasted with that reported with 1,4,8,1 l-tetraazacyclo-tetradecane-1,4,8,1 l-tetraacetic acid, in which the primary co-ordination sphere involves N202 co-ordination and two ringnitrogen atoms occupy the elongated axial sites.20 In this case astrong N, in-plane ligand field cannot be attained withoutsevere non-bonding steric interactions and the complex relaxesto the lower-energy structure observed.The copper and nickel complexes of the tricyclic tetraamineL" in aqueous solution give visible absorption spectra[h,,,(H,O) 538 and 450 nm respectively] typical of square-planar complexes with a strong ligand field (Table 1).Thecopper complex is resistant to attack by hydrogen sulfide inaqueous solution, consistent with high kinetic stability.Thevisible absorption spectrum was invariant in the range pH 1.4-11.4 showing that the complex was resistant to protonationover this range. In comparison [CuL'I2+ is also resistant toacid-catalysed decomplexation and dissociation may only beobserved in 6 mol dmP3 nitric acid.2' In these square-planarcomplexes with L15, the two piperazine rings must adopt boatconformations.ExperimentalReactions were carried out under a nitrogen atmosphereusing standard Schlenk techniques. Commercial solvents weredistilled from an appropriate drying agent prior to useaccording to standard procedures. Proton and carbon- 13 NMRspectra were recorded on a Bruker AC 250 spectrometeroperating at 250.1 and 62.9 MHz respectively.Chemical shiftsare given in ppm relative to SiMe, (6 0). Infrared spectra wererecorded as KBr discs or as a mull in Nujol with a Perkin-Elmer577 spectrometer or a Mattson-Sirius 100 FT spectrometer.Mass spectra were recorded on a VG 7070 E spectrometer witha FAB, CI, EI or DCI ionization mode (FAB, fast ato350 J. CHEM. SOC. DALTON TRANS. 1992Fig. 5 View of the unit cell showing the protonated lactam H2L14 '+ at the inversion centrebombardment; CI, chemical ionization; EI, electron impact;DCI, desorption chemical ionization), as stated.pH-Metric 7'itrations.-(i) Apparatus. The titration cell was adouble-walled glass vessel (capacity 5 cm3) which was main-tained at 25 "C, using a Techne Tempette Junior TE-8J.Titration solutions were stirred using a magnetic stirrer andkept under an atmosphere of nitrogen.Titrations were per-formed using an automatic titrator (Mettler DL20, 1 cm3capacity) and burette functions (volume increments and equili-bration time) were controlled by a BBC microprocessor. ThepH was measured using a Corning 001854 combination micro-electrode which was calibrated using buffer solutions at pH4.008 (H02CC,H4C02K, 0.05 rnol drn-,) and pH 6.865[KH2P04 (0.025 rnol dm-,)-Na2HP04 (0.025 rnol dm-,)].Data were stored on the BBC microprocessor and transferredto the MTS mainframe using KERMIT and subsequentlyanalysed by two non-linear least-squares programs SCOGS-2and SUPERQUAD."(ii) Acid-dissociation constants. Stock solutions of the ligaiidL" (0.002 rnol dm-,) in Milli-Q water (25.0 cm3) with nitricacid (0.004 rnol dm3) and tetramethylammonium nitrate (I =0.10 rnol dm-,) were prepared.In each titration 3.5 cm3 of thestock ligand solution was titrated with tetramethylammoniumhydroxide (0.109 rnol drn-,), the exact molarity of the which wasdetermined by titration against hydrochloric acid (0.100 rnoldm3).Synthesis qf' Ligands.-l,8- Dimethyl-4,11 -bis(toluene-p-sulj!fonj*l)- I ,4,8,11 -trtraa-?ac'~~c.lotetradecane, L' '. A mixture of1,8-bis(toluene-p-suIfonyl)- 1,4,8,11 -tetraazacyclotetradecane L4(0.51 g, 0.1 mmol), formaldehyde (1 cm3, 30% aqueous solution)and formic acid (1.2 cm3) was heated at 90" for 4 h. After coolinghydrochloric acid was added ( 5 cm', 6 rnol dm-,) and thesolution was evaporated. The residue was taken up in water(5 cm3), the pH adjusted to 2 1 3 (KOH) and the solutionextracted with dichloromethane (4 x 10 cm3).After evapor-ation and drying (K2C03) a colourless oil was obtained (0.48 g,86%); R, (10% MeOH-CH2C12) 0.70; m/z (DCI) 538 [ M +2]+ and 537 [ M + 11'; G,(CDCI,) 143.1 (s), 136.7 (s), 129.5,126.9 (d), 55.7, 55.4 (t), 47.6, 46.9 (CH,N), 43.1 (CH,N), 26.3(CH2C) and 21.3 (CH3-aryl); G,(CDCI,) 7.65 (4 H, d, ortho arylH, J7.7 Hz), 7.25 (4 H, d), 3.19 [8 H, t + t, CH,N(ts)], 2.49 (4 H,t, CH2N), 2.40 (6 H, s, CH,-aryl), 2.35 (4 H, t, CH,N), 2.15 (6 H,s, CH,N) and 1.73 (4 H, qnt, CH,C).1,8- Dibuty1-4,ll -bis( to/uene-p-su/fon),/)- 1,4,8,11 -tetraaza-cyclotetradecane, L'O. To a solution of L4 (0.51 g, 0.1 mmol) inacetonitrile (1 5 cm3) was added anhydrous potassium carbon-ate (0.26 g) and 1-iodobutane (0.39 g, 2.12 mmol), and themixture was heated to reflux for 48 h. After filtration andremoval of solvent, the residue was chromatographed on silica(2% MeOH-CH2CI2) to yield a colourless oil (0.27 g, 4373,which crystallised on standing, m.p.108-1 10 "C; m/z (DCI) 622[ M + 23' and 621 [ M + 13'; 8,-(CDCI,) 143.0, 136.6 (s),129.5, 127.0 (d), 55.0, 53.2, 51.2, 47.9, 47.3 (CH,N), 28.9, 26.3(CH2C), 21.3 (CH,-aryl) and 13.9 (CH,CH,); 6, 7.65 (4 H, d),7.30(4H,d),3.22[4H,t,CH2N(ts)],3.12[4H,t,CH2N(ts)],2.56(4 H, t), 2.41 (6 H, s, CH,-aryl), 2.3 1 (4 H, t). 1.70(4 H, t), 1.28 (8 H,m, CH,CH,) and 0.89 (6 H, t, CH,CH,).1,8-DibutyI- 1,4,8,1 1 -tetraa~(Ic:r,c./(~irt~~I~~c~(ine, L5.The diJ. CHEM. SOC. DALTON TRANS. 1992 35 1Table 6 Summary of cell data, data collection and refinement detailsCompound tr~ns-[NiL~][ClO,]~ ~is-[NiL'][C10,]~ [CuLS][PF612 [CNH 2 ~ 9 1 1 CCIo4I 2-2H,OFormulaMColour, habitCrystal size/mmCrystal systemaiAbIAC I A4"PI"rib u1A3Space groupZMolecular symmetryF ( o wCllcm-Dcalci$ cmMin., max. absorption20 range/T/OCReflections measuredUnique reflectionsReflections withNo. variables in leastp in weighting schemeR, R'correctionI > 30(I)squaresC, 8H40C12NiN408570.2Yellow, block0.29 x 0.33 x 0.57Triclinic9.214(2)9.3 15(2)8.507(2)113.90(1)104.64(2)75.52( 1)636.9(4)PT1T3021.4910.20.69,0.794 to 542128572857233 11870.0570.049,0.072C18H40C12NiN408570.2Orange, plate0.15 x 0.41 x 0.55Orthorhombic15.047(3)12.689(3)26.47 l(5)5054(2)Pnmal Pn2 a824161.5010.34 to 48- 10038002109Density in final differencemapie A-3 0.54Final shiftleuor ratio 0.02tosylamide L'O (0.34 g, 0.55 mmol) was treated with HBr-MeC0,H (15 cm3, 40%) and phenol (0.3 g) was added.Themixture was heated to 120 "C for 48 h, then cooled and filteredto yield a colourless precipitate of the tetrahydrobromide saltwhich was washed with diethyl ether (3 x 10 cm3) and dried(0.1 mm Hg, ca. 13.3 Pa), 0.32 g (9373, m.p. > 250 "C (Found: C,31.4; H, 6.85; N, 7.65. C,8H40N4~4HBr~3H,0 requires C, 31.3;H,6.95; N, 8.10%);m/z(DC1)314[M + 21' and 313 [ M + 13';6,-(D,O) 54.5, 46.3, 42.9, 39.7, 35.2 (CH,N), 24.8, 17.9, 16.6(CH,C) and 11.5 (CH,); aH(D20) 3.71 (8 H, br m, CH,N), 3.54(4 H, br t, CH,N), 3.45 (4 H, t, CH,N), 3.31 (4 H, m, CH2Nring), 2.16 (4 H, m, CH,CH,N), 1.75 (6 H, NH+CH,CH,), 1.40(4 H, qnt, CH,C) and 0.92 (6 H, t, CH,).1 3 - Dimethyl- 1,4,8,11 -tetraazacyclotetradecane, L6.Thiswas prepared in an analogous manner to the dibutyl compoundL5 in 87% yield; m.p. 2 240 "C (as fully protonated hydro-bromide salt) (Found: C, 25.6; H, 5.95; N, 10.00. Ct2H,,N4-4HBr.H20 requires C, 25.2; H, 5.95; N, 9.80%); m/z (DCI) 229[A4 + 13 +, 6,-(Dz0) 49.8,45.8,42.6,40.8 (CH,N), 36.5 (CH,N)and 18.0 (CH,C); 6,(D,O) 3.73 (8 H, br s, CH,N), 3.49 (8 H, m,CH2N), 3.03 (6 H, s, CH,N) and 2.18 (4 H, br qnt, CH,C).4-Butyl- 1,8-bis( toluene-p-sulfony1)- 1,4,8,11 -tetraazacyclo-terradecctne, L".To a solution of the ditosylamide L4 (0.25 g,0.05 mmol) in acetonitrile (10 cm3) was added anhydroussodium carbonate (0.1 1 g) and l-bromobutane (0.14 g, 1.02mmol) and the mixture was heated to reflux for 48 h. Afterfiltering and removing solvent, the residue was chromato-graphed on silica (5% MeOH-CH,CI,) to yield a colourlessgummy solid (0.11 g, 40%); R, (SO,, 10% MeOH-CH,CI,)0.48: mi: (DCI) 566 [ M + 2]+, 565 [ M + 11' and 564 [ M I ' ;G,(CDCI,) 143.5, 134.1 (s), 129.5, 127.2 (d), 53.7, 52.5, 50.7,49.6,49.1, 48.8, 47.3, 46.0, 45.1 (CH,N), 27.2, 25.8 (CH,C), 21.3(CH,-aryl), 20.3 (CH2C) and 13.8 (CH,CH,); G,(CDCI,) 7.63(4 H, d + d, o aryl H), 7.33 (4 H, d + d, m aryl H), 3.23 (4 H, t,C18H40CuF12N4P2666.0Pink, diamond0.07 x 0.56 x 0.65Triclinic9.357( 2)9.297( 2)8.552(2)1 12.60(2)103.63(2)77.3 I( 1)660.6(4)PT1T3431.6710.5cl 6H36C12CuN4014642.9Blue, block0.14 x 0.32 x 0.38Monoclinic8.089(4)9.269( 2)17.552(4)96.34(3)1308( 1)26701.6311.1P21lCiC2 8 5 2 c12 cu 8 1 4859.2Deep blue, plate0.30 x 0.25 x 0.24Triclinic9.547( 2)12.014( 2)8.929( 1 )98.97( 1 )114.56( 1)80.@( 2)914.2(6)PT1T45 11.568.20.59,0.93 0.71,0.864 to 5421 212944 33202423 28484 to 542420 1934170 1690.07 0.080.044,0.064 0.053,0.0750.70,0.824 to 542140973985264324 10.050.053,0.0810.650.010.670.0 10.920.02CH,N), 3.08 (4 H, t, CH,N), 2.71 (4 H, t, CH,N), 2.68 (4 H, t,CH,N), 2.43 (6 H, s, CH,-aryl), 1.92 (4 H, qnt, CH,C), 1.28 (4H, m, CH,C) and 0.92 (3 H, t, CH,CH,).1 -Butyf-8-rnethyl-4,11 -bis( toluene-p-sulfony1)- 1,4,8,11 -tetra-azacycfotetradecane, Lt3.This was prepared from L t 2 usingHC0,H-HCHO as described for L" in 89% yield; m/z (DCI)580 [ M + 2]', 579 [ M + 13' and 578 [MI+; &(CDC13) 7.65(4 H, d, J = 8.1 Hz), 7.31 (4 H, d), 3.24(4 H, t, CH,N), 3.15 (4 H,t, CH,N), 2.49 (4 H, t, CH,N), 2.42 (6 H, s, CH,-aryl), 2.35 (4 H,t, CH,N), 2.15 (3 H, s, CH,N), 1.73 (4 H, qnt, CH,C), 1.28 (4 H,m, CH2C) and 0.90 (3 H, t, CH,).1 -Butyi-8-methyl- 1,4,8,11 -tetraazacyclotetradecane, L'. Theditosylamide L t 3 was detosylated as described for L5, to yieldthe tetrahydrobromide salt as a colourless solid (90%) m.p.2240 "C (Found: C, 28.3; H, 6.80; N, 9.00. Cl,H,,N,~4HBr-2H,O requires C, 28.6; H, 6.65; N, 8.90%); m/r (DCI) 271 [M +13' and 270 [MI'; G,(CDCI,) 3.71 (8 H, m, CH,N), 3.44(4 H, m, CH,N), 3.32 (4 H, m, CH,N), 3.04 (5 H, qnt + t,CH,N + CH,N), 2.30 (4 H, qnt, CH,), 1.42 (4 H, m, CH,C)and 0.94 (3 H, t, CH,).The diamide 6,13-dioxo- 1,5,8,12-tetra-azatricyclo[ 10.2.2.25.8]octadecane Lt4 was prepared as de-scribed earlier.61,5,8,1 2-Tetraazatricyclo[10.2.2.25~8]octadecane, L' '. 6,13-Dioxo-1,5,8,12-tetraazatricyclo[ 10.2.2.25*8]octadecane (0.28 g,0.1 mmol) was treated with a solution of BH,-thf (40 cm', 1.0mol dm-, solution) in thf and the mixture was boiled underreflux for 36 h.After cooling to O"C, methanol (2 cm3) wasslowly added and solvent was removed under reduced pressure.The residue was treated with 6 mol dm-, HCl(20 cm3, 3 h), thenevaporated to dryness and the residue redissolved in potassiumhydroxide solution (10 cm3, 6 mol dm-3), extracted with di-chloromethane (3 x 20 cm3), dried (K,C03) and solventevaporated to yield a colourless solid (0.15 g, 60%); m.p. 8&82 "C (Found: C, 66.5; H, 11.4; N, 22.0. C19H,,N, requires C3 52 J. CHEM. SOC. DALTON TRANS. 1992Table 7standard deviations (e.s.d.s) in parenthesesPositional parameters for [NiL5][CI0,], with estimatedAtom Y 4'Ni 0.0 0.0 0.0N(1) 0.1971(3) -0.1446(3) -0.0079(3)C(2) 0.1896(5) -0.2560(4) -0.1933(4)C(3) 0.0370(6) -0.3056(4) -0.2581(5)N(4) -0.0774(3) - 0.1579(3) -0.21 8 l(3)( 3 5 ) -0.2272(5) -0.1979(4) -0.2375(5)C(6) -0.3544(4) -0.0554(4) -0.2 159(5)C(7) - 0.3339(4) 0.0680(4) - 0.0385(4)C(11) 0.2048(3) -0.231 l(3) 0.1 109( 3)C( 12) 0.3382(4) -0.3629(4) 0.1 11 8(4)C( 13) 0.3379(5) -0.4394(4) 0.2378(5)C(14) 0.3577(8) - 0.338 l(6) 0.4188(6)c1 0.1 786( 1) 0.2044(1) -0.291 5( 1)0(1)* 0.1 149(7) 0.091 l(6) -0.2505(8)O(2) * 0.3152(8) 0.199( 1) - 0.186( 1)O(3) * 0.23 I( 1) 0.088( 1) - 0.439( 1)O(4) * 0.057( 1) 0.2930(8) -0.352(1)0 ( 5 ) * 0.105(1) 0.343( 1) - 0.154( 1)(36) * 0.244( 1) 0.330( 1) -0.325( 1)0(7)* 0.163(2) 0.!97(2) -0.147(1)o m * 0.093 1) 0. I34( 1 ) -0.437(1)* The disordered oxygen atoms had occupancy factors of 0.55, 0.74,0.40,0.63,0.50,0.50,0.32 and 0.36 for O( 1)-O(8) respectively.Table 8parenthesesPositional parameters for [CuL5][PF6I2 with e.s.d.s inAtom Y Y0.00.197 5(2)0.180 9(4)0.028 l(4)-0.081 9(3)-0.231 8(4)-0.349 5(3)-0.328 6(3)0.210 2(3)0.349 l(4)0.352 8(4)0.383 7(7)-0.101 2(2)-0.103 2(3)- 0.008 9( 3)-0.216 2(4)-0.314 7(3)-0.222 8(3)- 0.162 76(9)0.0-0.151 8(2)-0.259 3(3)- 0.306 6(3)- 0.162 4(2)-0.196 9(3)- 0.054 O(4)0.069 7(3)-0.237 8(3)-0.358 6(3)- 0.434 8(4)-0.327 8(6)-0.213 67(9)-0.360 6(3)- 0.240 2(3)- 0.075 O(3)-0.196 8(3)-0.332 7(3)-0.101 2(2)0.0-0.011 l(3)- 0.193 6(4)-0.251 3(4)-0.218 4(3)-0.228 2(4)-0.204 1(4)-0.027 8(4)0.109 4(3)0.1 15 9(4)0.244 8(4)0.427 5(5)0.284 62(9)0.223 6(2)0.131 O(3)0.399 5(3)0.441 O(3)0.167 9( 3)0.342 8(3)Table 9e.s.d.s in parenthesesPositional parameters for [Cu(H,L9)][CIO,],.2H,O withxo.Oo0 0-0.071 4(4)0.01 1 O(6)0.185 7(6)0.181 5(4)0.348 8(5)0.356 5(5)0.255 O ( 5 )0.01 1 4(6)- 0.125 5(5)- 0.174 4(4)-0.177 6(5)-0.369 6(5)-0.336 O(2)- 0.183 5(9)- 0.467 O( 7)-0.325 5(9)-0.368 3(6)0.151 4(6)4'o.Oo0 0 o.Oo0 0- 0.18 1 3(4) - 0.064 2(2)-0.300 9(5) -0.017 3(3)-0.259 7(5) 0.011 5(3)- 0.129 7(4) 0.060 8(2)-0.058 3(5) 0.065 8(3)0.084 5(5) 0.109 2(3)0.204 6(5) 0.070 5(3)0.180 O ( 5 ) 0.141 4(2)0.070 3(5) 0.148 7(2)-0.014 l(3) 0.099 6(2)- 0.177 9( 5 ) 0.138 9(3)-0.129 l(4) 0.245 7(2)-0.471 7( 1) 0.I 38 98(7)-0.436 l(9) 0.179 l(5)-0.390 6(6) 0.165 5(4)-0.448 8(7) 0.062 5(3)-0.618 4(5) 0.151 3(3)0.075 8(4) 0.217 O(2)Table 10e.s.d.s in parenthesesPositional parameters for [CUL~][H,L'~][C~O,], withx0.0- 0.1 294(4)- 0.05 18(6)0.1 199(6)0.1683(4)0.3260( 5 )0.3 794( 5 )0.2962(5)-0.1 160(5)0.01 59(4)0.0700(3)0.0580(4)0.2408(4)0.1224(5)0.321 8(4)0.396 1(5)0.5 1 9 1 ( 5 )0.6498( 5 )0.3160(5)0.3788( 5 )0.48 13(4)0.2726( 1)0.1 836(8)0.1978(7)0.4084( 7)0.2750( 14)0. 1959(5)4'0.0-0.0848(3)- 0.0636(4)- 0.0857(4)- 0.0 133( 3)- 0.0505(4)0.0309(4)0.0364(4)- 0.2084( 3)- 0.2508( 3)-0.1819(2)- 0.3550( 2)0.59 14(3)0.5774(4)0.5535(4)0.62 14( 3)0.6070(4)0.5048(4)0.5152(3)0.6932( 3)0.6903( 3)0.7488(3)0.2566( 1)0.1722( 5 )0.3377(6)0.2358(7)0.2849( 10)0.0- 0.2280(4)-0.3313(5)-0.2431(6)-0.0843(4)0.0340(7)0.1857(7)0.2994(6)-0.2147(5)- 0.0597( 5)0.0624(3)0.24 1 O(4)0.3025(6)0.48 18(6)0.5832( 4)0.761 l(5)0.7975(5)0.75 1 3( 5 )0.3 382( 5 )0.523 l(5)0.6090(4)- 0.0657(4)-0.2260( 1)-0.272 l(8)-0.3264(9)-0.2352(11)- 0.08 19(9)66.7; H, 11.1; N, 22.2%); m/z (DCI) 254 [ M + 2]+ 253 [ M +13 + (100%) and 252 [ M I '; G,(CDC13) 55.8,49.4 (CH2N) and23.5 (CH,C); SH(CD2C12) 3.14 (8 H, m, CH,N piperazine), 2.70(8 H, t, J 5.5 Hz, CH,CH,N), 2.39 (8 H, m, CH,N piperazine)and 1.62 (4 H, qnt, CH,CH,CH,).1,8-N,N'-Bis(carboxymethyI)- 1,4,8,11 -tetraazacyclotetra-decane, H,L8, was prepared as reported previously.61,8-N,N'- Bis( carbo.uymeth~ll)-4,11 -dimethyl- 1,4,8,11 -tetra-u=uc~'c./otetradecune, H2L9.The diacid H2Ls (0.1 g, 0.32 mmol)was heated to reflux with formaldehyde solution (37%, 1.5 cm3)and formic acid (1.7 cm3) for 4 h. Hydrochloric acid (1 moldm-3, 20 cm3) was added to the cooled solution and the mixturewas heated for a further 10 min. On cooling a crystalline solid(the dihydrochloride salt) formed which was collected byfiltration and dried (98 mg, 74%), m.p. 3 240 "C; m/z (DCI) 346[ M + 2]+ and 345 [ M + 13'; G,(D,O) 2.05 (4 H, qnt, CH,C),3.48 (8 H, m, CH,N) and 3.64 (4 H, s, CH,CO).2.89 (6 H, S, CH,N), 3.00 (4 H, t, CHIN), 3.23 (4 H, t, CHZN),Complex Formution-The following examples are represent-ative.[NiL5][C104]2.To a solution of the ligand L5 (62 mg, 0.2mmol) in methanol (4 cm3) was added a solution of nickelperchlorate hexahydrate (74 mg, 0.2 mmol) in methanol (1 cm3).After removal of solvent, the orange residue crystallised fromwater during slow evaporation to yield orange prismaticcrystals (75 mg, 66%) (Found: C, 37.6; H, 7.20; C1, 12.2; N, 10.1;Ni, 10.1. C18H4,C12N4NiOs requires C, 37.9; H, 7.00; CI, 12.45;N, 9.80; Ni, 10.3%); m/z (FAB. m-nitrobenzyl alcohol matrix)571 [ M + 11'; h,,,(H,O) 461 nm ( E 50 dm3 mol-' cm-').On further concentration of the mother-liquors and allowingthe solution to evaporate slowly, plate-shaped crystals weredeposited over a period of 7 d; h,,,(H20) 473 nm ( E 48 dm3mol-' cm-') (Found: C, 38.0; H, 7.30; N, 9.65.C18H4,C12N,-NiOs requires C, 37.9; H, 7.00; N, 9.80"/;;)J. CHEM. SOC. DALTON TRANS. 1992 353[CuL9][C10,],. To a solution of the H2L9*2HCI (26 mg,0.05 mmol) in water (2 cm3) was added a solution of copper(I1)perchlorate hexahydrate (19 mg, 0.05 mmol) in water (1 cm3).The pH was raised to 3 by careful addition of dilute potassiumhydroxide solution, the mixture filtered and the solutionallowed to stand. After 48 h at room temperature, blue crystalshad deposited, which were collected by filtration, washed withcold water and dried in air (25 mg, 78%) (Found: C, 29.6; H,5.80; C1, 11.2; N, 8.60. Cl,H3,C1,CuN,01, requires C, 29.9; H,5.60; C1, 11.0; N, 8.70%); h,,,(H20) 573 nm (E 75 dm3 mol-'cm-').Structural Analyses.-Details of the X-ray experimental con-ditions, cell data, data collection and refinement are sum-marked in Table 6.For compounds trans-[NiL5][C10,],,[CuL5][ PF,] ,, [Cu(H2L9)][C10,] 2*2H20 and [CuL8]-[H, L',] [ClO,] ,, complete structural analyses are reported.The cell and intensity data were collected with an Enraf-NoniusCAD-4 diffractometer using graphite monochromated Mo-Karadiation. All calculations were carried out on a PDPll-73computer system using the SDP-Plus system of programs anddata therein.23 The structures were solved by the heavy-atommethod. Hydrogen atoms (visible in difference maps) wereallowed for, and refinement was by full-matrix least-squarescalculations with all non-H atoms allowed anisotropic motion.Selected dimensions are in Tables 2-5, fractional coordinatesare in Tables 7-10.Additional material available from the Cambridge Crystallo-graphic Data Centre comprises H-atom coordinates.thermalparameters and remaining bond lengths and angles.The structure of cis-[NiL5][C10,], presented some diffi-culties (as noted in the Discussion section). The crystals onlydiffracted poorly at room temperature and even at - 100 "C wecould not obtain enough data adequately to define the structure(presumably because of disorder in the crystal lattice). Thesystematic absences allow the space group to be either Pnma orPn2,cr. A satisfactory solution to the Patterson function wasfound in the centrosymmetric space group with the asymmetricunit containing two independent half-cations having their Niatoms on mirror planes and four 'half' perchlorate anions withthe chlorine atoms on mirror planes.This situation thendemands that the cations be disordered. Solution in the non-centrosymmetric space group was also considered (in this casethere would be two independent cations in the asymmetric unit)but led to the same impasse as with the centrosymmetricsolution (with a pseudo-centrosymmetric map and very poorresolution). Work on this structure was then abandoned.AcknowledgementsWe thank the SERC and WR Grace for support under theCASE scheme and the Natural Science and EngineeringResearch Council (Canada) for continued support via operatinggrants. Drs. P. McArdle and D. Cunningham (UniversityCollege, Galway) are also thanked for their assistance incollecting an intensity data set at - 100 "C for cis-[NiL5]-[c10412.References1 L.F. Lindoy, The Chemistry qf Macrocyclic Ligand Complexes,Cambridge University Press, Cambridge, 1989.2 Th. A. Kaden, Top. Curr. Chem., 1984,121, 157.3 E. Kimura, Coord. Chem. Rev., 1986, 15, 1; T. R. Wagler and C. J.Burrows, J. Chem. SOC., Chem. Commun., 1987, 277; J. R. Morphy,D. Parker, R. Alexander, A. Bains, A. F. Carne, M. A. W. Eaton,A. Harrison, A. Millican, A. Phipps, S. K. Rhind and R. Titmas,J. Chem. SOC., Chem. Commun., 1988, 156; M. Ciampolini, M.Michelani, N. Nardi, P. Paoletti, P. Dapporto and F. Zanobini, J.Chem. Soc., Dalton Trans., 1984, 1357.4 D. Tschudin, A. Basak and Th. A. Kaden, Helv.Chim. Acta, 1988,71,100; M. Ciainpolini, L. Fabbrizzi, A. Perotti, A. Poggi, B. Seglin andF. Zanobini, Inorg. Chem., 1987, 26, 3527; M. Studer and Th. A.Kaden, Helv. Chim. Acta, 1986,69,2081.5 I. M. Helps, J. Chapman, D. Parker and G. Ferguson, J. Chem. SOC.,Chem. Commun., 1988,1094.6 I. M. Helps, D. Parker, J. R. Morphy and J. Chapman, Tetrahedron,1988,45, 2 19.7 V. J. Thorn, C. C. Fox, J. C. A. Boeyens and R. D. Hancock, J. Am.Chem. SOC., 1984,106,3198.8 (a) T. W. Hambley, J. Chem. SOC., Dalton Trans., 1986, 565; (b) Z.Krajewski, Z. Urbanczyk-Lipkowska and P. Gluzinski, Bull. Acad.Pol. Sci. Ser. Chim., 1977,25, 853.9 J. R. Morphy, D. Parker, R. Kataky, M. A. W. Eaton, A. T. Millican,R. Alexander, A. Harrison and C. Walker, J. Chem. Sot.., PerkinTrans. 2, 1990, 573.10 M. E. Phelps and J. C. Mazziotta, Science, 1985, 228, 799; A. DelGuerra, Phys. Scr., 1987, T19,481.11 S. Jurisson, E. 0. Schlemper, D. E. Troutner, L. R. Canning, D. P.Nowotnik and R. D. Neirinckx, Inorg. Chem., 1986,25, 543.12 Xu Jide, Ni Shisheng and Lin Yujuan, Inorg. Chim. Acta, 1986, 11 I,61; Inorg. Chem., 1988,27,4651.13 R. D. Hancock, S. M. Dobson, A. Evers, P. W. Wade, M. P.Ngwenya, J. C. A. Boeyens and K. P. Wainwright, J. Am. Chem. Soc.,1988,110,2788.14 Critical Stability Constants, eds. A. E. Martell and R. M. Smith,Plenum, New York, 1975, vol. 2.15 L. Fabbrizzi, J. Chem. SOC., Dalton Trans., 1979, 1857.16 J. W. Chang and R. B. Martin, J. Chem. Phj,s., 1969,73, 4277.17 R. W. Hay, B. Jeargh, G. Ferguson, B. Kaitner and B. L. Ruhl,18 P. A. Tasker and L. Sklar, J. Cryst. Mol. Struct., 1975,5, 329.19 A. Pajunen and E. Luukonen, Suom. Kemistil. B, 1969,42,348.20 A. Riesen, M. Zhender and Th. A. Kaden, J. Chem. SOC., Chem.Commun., 1985, 1336; M. K. Moi, M. Yanuck, S. V. Deshpande, H.Hope, S. J. DeNardo and C. F. Meares, Inorg. Chem., 1987,26,3458.21 L.-H. Chen and C.-S. Chung, Inorg. Chem., 1988.2- 1880.22 P. Gans, A. Sabatini and A. Vacca, J. Chem. Soc., Dalton Trans., 1985,1 196.23 B. A. Frenz and Associates, Inc., SDP Structure DeterminationPackage, College Station Texas and Enraf-Nonius. Delft, 1983.J . Chem. Sot.., Dalton Trans., 1982, 153 1.Received 24th Julji 199 1 ; Paper 1 /03807

ISSN:1477-9226    

DOI:10.1039/DT9920000345

出版商:RSC    

年代:1992

数据来源: RSC