摘要:

J. CHEM. SOC. DALTON TRANS. 1992 2765Geometrical Isomerism in 2-Hydroxypyridinate and2-thiolate Complexes derived from the Ruthenium(Bis(ally1) Dimer [{Ru(q3 : ~3-CloH16)Cl(p-Cl)}2] tJonathan W. Steed and Derek A. Tocher *Department of Chemistry, University College London, 20 Gordon St., London WC 1 H OAJ,Pyridine-v)UKReaction of the ruthenium(1v) chloro-bridged dimer [{Ru(q3: q3-Cl,H16)CI(p-CI)}2] with a range of 2-hy-droxypyridinate and pyridine-2-thiolate ligands (HL = 2-hydroxypyridine, 6-chloro-2-hydroxypyridine,2- hydroxy-6-methylpyridine,2- hydroxy-4-methylquinoline,8- hydroxyquinoline,pyrrolidin-2-one,quino-line-2-thiol and 6-methylpyridine-2-thiol) gives the neutral, chelate compounds [Ru(q3: q3-CloH16)Cl( L)]each of which exists as both axial and equatorial geometric isomers.These isomers occur in varyingratios and may be distinguished by their characteristic 'H NMR spectra. The X-ray crystal structures ofeq- [Ru(q3: q3-C,oH16)CI{NC6H3(0)CI-6}] and of eq- [Ru(q3: q3-C10H16)C((NC9H6S)] are reported.Recent interest has focused strongly on the chemistry ofthe hitherto neglected ruthenium(1v) bis(ally1) chloro-bridgeddimer [ { Ru( q : q 3-c ,H 6)C1(p-cl)} ,] 1 7*8 especially in con-nection with ligands related to pyridine-2-thi01,~ which are ofconsiderable interest in their own right.'.'' Previously we haveinvestigated the reactions of the closely related ruthenium(r1)arene complexes [{ Ru(q6-arene)C1(p-Cl)},] ' with a range ofligands related to 2-hydroxypyridine and with a wide range of1,3,5, C,H,Me,-1,2,4,5 or C6Me,).13 Cotton and co-workers l4have also characterised the complex [Ru(p-MeC,H,CHMe,)-Cl(NC,H,O)].Toerien and van Rooyen recently demon-strated that the reaction of 1 with benzothiazole-2-thiol(N,C,H,SH) and pyridine-2-thiol (NC,H,SH) proceeds via atwo-step process initially involving bridge cleavage to give aneutral complex ex ibiting equatorial co-ordination of thepyridyl nitrogen ato . Subsequent refluxing of these complexesin solutions contai ing Na,[C03] brings about the intra-molecular loss of HCl and gives complexes containingN,C7H,S and NC, ,S as anionic chelates.2-H ydroxypyridin 1 has been shown to co-ordinate initiallythrough the pyridone oxygen atom in ruthenium(r1) arenesystems, at room temperature, to give complexes such as[Ru(qh-C,H,)C1,(OC5H4NH)] 2.Subsequent deprotonationon refluxing forms the chelate complex [Ru(q6-C6H6)CI(NC5-H,O)] 3, which is related to those described by Toerien and vanRooyen for the ruthenium(1v) system. These workers alsoattempted the reaction of 1 with 2-hydroxypyridine but wereunable to identify the products formed. As an extension to ourprevious work we now report the reactions of 1 with a range ofligands related to 2-hydroxypyridine and pyridine-2-thiol.The geometry about the ruthenium ion in complex 1 is looselydescribed as trigonal bipyramidal with chloride ligandsoccupying the axial sites and one equatorial position, while thebis(ally1) ligand is in the remaining two equatorial sites.Complex 1 has been shown to exist as two diastereoisomers, ofC, and C', ~ymmetry,~ which arise as a consequence of thechirality of the 'CIOHl6Ru' unit.This phenomenon is readilyobserved in the 'H NMR spectrum which displays eight linescorresponding to the terminal allyl protons and four resonancesattributable to the methyl substituents. Mononuclear speciesderived from 1, while existing as two enantiomers, displaycarboxylates (arene = C6H6, p-MeC,H,CHMe,, C6H3Me3-t Supplementury data available: see Instructions for Authors, J . Chem.Soc., Dalton 7runs., 1992, Issue I , pp. xx-xxv.Ci isomerC2 isomer1signals corresponding to only a single diastereoisomer (fourterminal allyl and two methyl resonances) if the two halves ofthe bis(ally1) ligand are inequivalent (4.g. as a consequence ofinequivalent axial sites of the trigonal bipyramid 3 * 5 9 1 5 ) or, inthe more symmetrical equatorially substituted compounds[ R U ( ~ ~ : ~ ~ - C ~ , H , ~ ) C ~ , L ] (L = pyridine, PPh,, PF,, CO,Bu'CN, etc.),16 two terminal allyl and a single methyl resonance.Results and DiscussionIn our previous study we showed that the chelate complex[Ru(r16-C6H6)CI(02CCF3)] was a useful synthetic precursorto 3 and related products.This synthetic route is not availablein the case of the bis(allyl)ruthenium(Iv) system, however, sincethe reaction of 1 with trifluoroacetic acid or silvertrifluoroacetate gives the relatively inert aqua complex[Ru(q3 : q3-CloH16)(02CCF3)2(oH2)].17 Fortunately, we findthat direct interaction of 1 with 2-hydroxypyridine in CH,Cl,at room temperature gives a good yield (ca.70%) of an orange-red complex 4. The infrared spectrum showed no bandsattributable to v(0H) or to v(NH) but did display a band at1596 cm-' (cJ: 1585 cm-' for Tl[NC,H,O] and 1635 cm-' forthe free ligand ") which is tentatively attributed to v,,,,(OCN)of the co-ordinated hydroxypyridinate anion. The assignmen2766 J. CHEM. SOC. DALTON TRANS. 1992of v,,,(OCN) at lower wavenumber is ambiguous due to thepresence of bands arising from the pyridyl ring. A weak band isalso observed at 317 cm-’ corresponding to v(RuC1). The ‘HNMR spectrum shows the characteristic four-line pattern(Table 1) for the terminal allyl protons of the 2,7-dimethylocta-2,6-diene-1,8-diyl ligand (6 5.05, 4.24, 4.07 and 3.00) and tworelatively widely separated signals for the methyl substituents(6 2.38 and 2.24) indicative of inequivalent axial sites on thetrigonal-bipyramidal ruthenium atom.A fast atom bombard-ment (FAB) mass spectrum displayed a strong molecular ionpeak at m/z = 367 (based on lo2Ru and 35Cl) with the expectedisotope distribution pattern. Fragmentation peaks associatedwith loss of a single chloride ligand and loss of both chlorideand hydroxypyridinate ligands were also observed, and a peakat m/z = 136 is due to the 2,7-dimethylocta-2,6-diene-1,8-diylligand. These observations, in conjunction with microanalyticaldata, lead us to formulate 4 as a chelate complex [Ru(q3:q3-CloHl6)C1(NC5H,O)], which is structurally related to 3 and tothe complexes prepared by Toerien and van Rooyen.’ It wasalso noted that the ‘H NMR spectrum of crude 4 produced inthis way showed small traces of a second compound with onlytwo terminal allyl resonances (6 4.90 and 4.04) and a broad peakat 6 10.40.We were unable to isolate this second product buttentatively suggest it to be an analogue of the ruthenium(I1)monodentate pyridone adduct [Ru(q6-C6H6)C1,(OC5H4NH)],for which the amine proton is observed at 6 11.56. The readyformation of chelate complexes such as 4 markedly contrastswith studies on the pyridine-2-thiolate analogue^,^ and isattributed to the greater acidity of the hydroxyl proton.Unlike its ruthenium(I1) arene analogues, 4 might be expectedto exist as two geometrical isomers (4a, 4b) distinguishable by‘H NMR spectroscopy, as a consequence of the stereochemicalinequivalence of the axial and equatorial sites of the trigonal-bipyramidal ruthenium atom.However, both [Ru(q3 : q 3-C,0-H 16)C1(N2C7H5S)] and [Ru(q3 : q3-CloH16)C1(NC5H4S)]are reported to exist solely as equatorial isomers (type a), withthe pyridyl nitrogen atom occupying the equatorial site of thetrigonal-bipyramidal ruthenium atom. The ‘H NMR spectrumof 4 (obtained from a sample synthesised by direct interactionof 1 with the non-deprotonated 2-hydroxypyridine ligand) isinterpreted in terms of a single isomer, possessing a set ofresonances qualitatively similar, in the allyl region, to thoseexhibited by [Ru(q3:q3-CloH16)CI(N2C7H5S)1 and [Ru-(q3 : q3-CloH 6)C1(NCsH$)].5It might be supposed that, analogously to the ruthenium(I1)arene system,’ 2-hydroxypyridine would react with compound1 in a two-step process, co-ordinating initially via the pyridoneoxygen atom at the equatorial site of the ‘CloH16RUCI2’ unit (asobserved in all previous cases of monodentate co-ordination tothe CloH16RUC12 unit 3,4*6,16 and suggested by the ‘H NMRspectrum of the trace product described above).Subsequentdeprotonation of such an adduct would then be expected to givea complex possessing a pyridyl ring occupying an axial site, ageometry at variance with that observed crystallographicallyfor [Ru(q3 :~3-C,oH,6)C1(N2C,H5S)].5 However, at somestage in the reaction a rearrangement must take place such thatthe relatively unhindered pyridone oxygen atom of the 2-hydroxypyridinate ligand preferentially occupies the morehindered axial site.This proposal is consistent with theisomerisation of 1 in MeCN ~olution,~ where the predominantspecies is observed to be a monomeric, bridge-cleaved complexwith a chloride ligand in the equatorial position and theacetonitrile axially located.Indirect evidence for an intramolecular rearrangement of apyridone intermediate in the formation of compound 4 comesfrom reaction of sodium 2-hydroxypyridinate with 1. Again themajor product (95%, evaluated by integration of the ‘H NMRspectrum) consists of the isomer 4a, however smaller quantitiesof a geometric isomer 4b are also observed. The ‘H NMR dataof 4b are in Table 1.This reaction, which uses the performedanionic ligand, presumably increases the rate of the chelationstep such that there is insufficient time for the equatorial-axialrearrangement to occur and hence a significant quantity of theless-stable axial isomer is observed.In an attempt to confirm the formulation of 4a and 4band synthesise further compounds displaying both axial andequatorial pyridyl fragments, we investigated the reaction of1 with 6-chloro-2-hydroxypyridine, 2-hydroxy-4-methylquino-line and 2-hydroxy-6-methylpyridine. These ligands containbulky ortho substituents which might be expected to interactunfavourably with the remaining axial chloride ligand incomplexes of type a and thus may display less preference for theequatorial form, Reaction with the neutral pyridinols was foundto be slow at room temperature and significantly more efficientconversions were obtained through use of the sodium salts ofthe ligands or addition of anhydrous sodium carbonate tothe reaction mixtures.In this way compounds of formulaH16)Cl(NC9H5(o)Me-4}] 6 and [Ru(q3 : q3-CloHl 6)Cl(NC5-H,(O)Me-6)] 7 were obtained (C,H,N analysis) in good yields.Like 4, complexes 5-7 display no bands attributable to v(0H)or v(NH) in their infrared spectra but possess peaks at 1589 (5),1550 (6) and 1558 cm-’ (7) tentatively assigned to v,,,,(OCN)as well as peaks arising as a consequence of pyridyl C=Cmodes ’ (see Experimental section) and bands due to v(RuC1).The ‘H NMR spectra of these materials proved complex,each possessing two sets of signals, present in a ratio ofapproximately 3 : 1 in the case of 5,6 : 1 for 6 and 3 : 2 for 7.Thespectrum of 5, for example, displays four singlets for the majorproduct due to terminal allyl protons (6 5.25,4.36,4.27 and 4.96)and two methyl resonances (6 2.32 and 2.16) and similarly theminor product 5b displays resonances at 6 4.95, 4.66, 4.56 and3.73 (terminal allyl) and 2.49 and 2.37 (methyl). These spectracould conceivably be attributed to pairs of diastereoisomers of5 7 if the compounds were dimeric, since binuclear compoundscontaining two ‘q3:q3-CloH16Ru’ units have been shown todisplay a total of eight terminal allyl resonances and four methylsignal^.^.'^-^^ Ho wever, electron-impact mass spectra exhibitstrong molecular ion peaks at m/z 401 (5), 431 (6) and 381 (7)with isotope distribution patterns consistent with the presenceof a single ruthenium atom in each case, implying the formationof mononuclear complexes.The mononuclear nature of 5 wasconfirmed by a single-crystal X-ray structure determination (seebelow). Fractional crystallisation of 5 from an acetone solutiongave red-brown crystals of a single isomer which was shown tobe the major isomer 5a, by low-temperature dissolution of thecrystalline material and simultaneous recording of its ‘H NMRspectrum (193 K). The structure determination (Fig. 1) showed5a to be a mononuclear chelate compound, with the nitrogenatom equatorial, closely related to the equatorial structureassigned to 4a, and observed crystallographically in the case of[Ru(q3 :q3-CloH16)C~(N,C7H,S)].5 Complex 5b is thereforeassigned a similar structure with the pyridyl nitrogen atomaxial.By analogy, similar isomeric structures are assigned to 6a,6b and 7a, 7b. The major products are assigned the structureswith the nitrogen atoms equatorially co-ordinated, allowing thebulky pyridyl fragments to avoid the axial sites which aresterically crowded by the methyl groups of the bis(allyl), 2,7-dimethylocta-2,6-diene- 1,8-diyl ligand.Good evidence for the equatorial nature of compounds 4a-7acomes from their ‘H NMR spectra which, in common withthose of [Ru(q3: q3-C loH, ,)C1(N2C7H,S)] and [Ru(q3 : q3-CloH,6)Cl(NC,H4S)],5 have the two central resonances, due tothe terminal allyl protons, occurring at very similar chemicalshifts. The pattern differs markedly from that observed for4b7b and [Ru(q3:q3-ClOHl6)CI(L-L)][BF4] ’’ (L-L = 2,2‘-bipyridyl or 1 ,lo-phenanthroline) where one of these resonancesis shifted significantly upfield relative to the other three, possiblyas a consequence of ring-current effects of the aromatic moiety.Another observation which may serve to distinguish betweenthe two possible isomers is the differences in the resonancesassigned to the internal allyl protons.In the case of 4a-7a these[Ru(q3 : q 3-CloH 16)C1{ NCSH,(O)CI-6)] 5, [ R u ( ~ : 11 3-C,0Table 1 Proton NMR data for neb complexes"Compound4a [ Ru( q : q 3-C ,HI ,)CI(NC,H,O)]( N equatorial)4b [ Ru(q3 : q3-C ,H ,)C1( NC,H,O)](0 equatorial)5a [ Ru(q3 : q3-C I ,H Ih)C1( NC,H,(O)CI-6)]( N equatorial)5b [ Ru( q : q "C 1 OH 1 6)CI { NC,H 3(O)C1-6)](0 equatorial)6a [Ru(q : q 3-C ,H ,)CI{NC,H ,(O)Me-4)](N equatorial)6b [ Ru(v3 : q3-C1 ,H ,)C1{ NC,H,(O)Me-4}](0 equatorial)7a [I Ru(q : 7 3-C ,H ,)Cl{NC,H,(O)Me-6}](N equatorial)7b [ Ru(q : q '-C ,H ,)C1{ NC,H ,(O)Me-6 )](0 equatorial)8a [Ru(q3 : q3-CloH ,)CI(NC,H,O)](N equatorial)Terminal ally15.05 (s, 1 H)4.24 (s, 1 H)4.07 (s, I H)3.00 (s, 1 H)5.24 (s, 1 H)4.69 (s, 1 H)4.36 (s, 1 H)3.24 (s, 1 H)5.25 (s, 1 H)4.36 (s, 1 H)4.27 (s, 1 H)2.96 (s, 1 H)4.95 (s, 1 H)4.66 (s, 1 H)4.56 (s, 1 H)3.73 (s, 1 H)5.31 (s, 1 H)4.43 (s, 1 H)4.36 (s, 1 H)2.97 (s, 1 H)5.15 (s, 1 H)4.80 (s, I H)4.56 (s, I H)3.53 (s, 1 H)5.21 (s, 1 H)4.31 (s, 1 H)4.30 (s, 1 H)2.91 (s, 1 H)5.10 (s, 1 H)4.77 (s, 1 H)4.51 (s, 1 H)3.70 (s, 1 H)4.34 (s, 1 H)3.98 (s, I H)3.87 (s, I H)2.70 (s, 1 H)Internal ally14.19 (m, 1 H)3.46(m, 1 H)4.40(m, 1 H)3.31 (m, I H)4.32(m, 1 H)3.59 (m, 1 H)4.81 (m, 1 H)4.56 (t, 1 H, = 5.4)4.43 (m, 1 H)3.64 (m, 1 H)4.62 ( t , I H, 35 = 5.6)4.39 (m, 1 H)4.37(m, 1 H)3.56 (m, 1 H)4.61 (t, 1 H, 3J = 6.2)4.14(m, 1 H)Et h y lenic2.78 (m, 4 H)2.78 (m, 4 H)2.69 (m, 4 H)2.69 (m, 4 H)2.76 (m, 4 H)2.65 (m, 4 H)2.73 (m, 4 H)2.59 (m, 4 H)4.95 (AXX', I H, 3J = 6.2)4.37 (AXX', 1 H, ' J = 5.6)3.22 (m, 2 H)2.72 (m, 1 H)2.64 (m, 1 H)Me2.38 (s, 3 H)2.24 (s, 3 H)2.42 (s, 3 H)2.12 (s, 3 H)2.32 (s, 3 H)2.16 (s, 3 H)2.49 (s, 3 H)2.37 (s, 3 H)2.39 (s, 3 H)2.21 (s, 3 H)2.45 (s, 3 H)2.30 (s, 3 H)2.36 (s, 3 H)2.17 (s, 3 H)2.33 (s, 3 H)2.1 1 (s, 3 H)2.41 (s, 3 H)2.08 (s, 3 HTable I (continued)9b [Ru(q3 :~3-C10Hl,)CI(NC4H,0)](0 equatorial)11 [Ru(q3 : q3-C,oH 6)CI,{NC,H,(SH)Me-6}]12a [RU(q3 :q3-CloH,,)CI(NC9H,S)](N equatorial)12b [Ru(q3 q3-CloH 1 ,)CI(NC,H,S)](S equatorial)13a [ Ru(q : q ,-C, ,H , ) a { NC, H,(S)Me-6)](N equatorial)13b [Ru(q3 : q3.-ClOH I ,)Cl{NC,H3(S)Me-6)](S equatorial)Terminal allyl4.87 (s, 1 H)4.58 (s, 1 H)4.02 (s, 1 H)3.09 (s, 1 H)5.14 (s, 1 H)4.25 (s, 1 H)4.16 (s, 1 H)2.81 (s, 1 H)5.22 (s, 1 H)4.63 (s, 1 H)4.51 (s, 1 H)d3.15 (s, 1 H)d4.85 (s, 2 H)4.17 (s, 2 H)d4.80 (s, 2 H)4.16 (s, 2 H)d5.00 (s, 1 H)4.57 (s, 1 H)4.19 (s, 1 H)3.14 (s, 1 H)4.95 (s, 1 H)4.49 (s, 1 H)4.31 (s, 1 H)3.45 (s, I H)4.91 (s, 1 H)4.45 (s, 1 H)4.15 (s, 1 H)3.10 (s, 1 H)5.02 (s, I H)4.88 (s, 1 H)4.65 (s, 1 H)3.88 (s, 1 H)Internal allyl5.13 (m, 1 H)4.15 (m, 1 H)4.06(m, 1 H)3.29 (m, 1 H)4.32 (m, 1 H)3.72 (m, 1 H)5.16 (m, 2 H)5.09 (m, 2 H)4.88 (m, 1 H)4.06 (m, 1 H)4.63 (m, 1 H)4.43 (m, 1 H)4.79 (m, 1 H)3.96 (m, 1 H)5.02 (t, 1 H, 33 = 3.9)4.66 (m, 1 H)Et h ylenic3.22 (m, 2 H)2.72 (m, 1 H)2.64(m, 1 H)2.70 (m, 4 H)2.47 (m, 4 H)3.24 (m, 2 H)2.54 (m, 2 H)3.20 (m, 2 H)2.52 (m, 2 H)2.68 (m, 1 H)2.49 (m, 3 H)2.68 (m, 1 H)2.49 (s, 3 H)2.36 (m, 4 H)2.72 (m, 2 H)2.58 (m, 2 H)Me2.54 (s, 3 H)1.71 (s, 3 H)2.29 (s, 3 H)2.18 (s, 3 H)2.36 (s, 3 H)2.27 (s, 3 H)2.33 (s, 6 H)2.29 (s, 6 H)2.53 (s, 3 H)2.36 (s, 3 H)2.46 (s, 3 H)2.05 (s, 3 H)2.64 (s, 3 H)2.31 (s, 3 H)2.79 (s, 3 H)2.48 (s, 3 H)a In CDCI,, s = singlet, d = doublet, J(H-H) in Hz, t = triplet, m = multiplet.Coupling constant unmeasurable due to overlapping signals of majorbroader than those arising from other terminal allyl protons on the same moleculeJ. CHEM. SOC. DALTON TRANS. 1992 2769X = H(4), C1(5), Me(7)Equatorial isomer (type a) Axial isomer (type b)4aSa7a4b5b7b8a 8boccur as two broad, poorly resolved, singlet-like resonances at 6cn.4.3 and 3.5. Conversely, the spectra of 4b7b display thecorresponding resonances as much sharper signals at 6 ca. 4.7and 4.2 4.5, one occurring as a virtual triplet and the other as awell resolved five-line multiplet.To confirm these observations the reaction of compound 1with 8-hydroxyquinoline (NC9H60H) was examined, Bothisomers resulting from this reaction might be expected topossess an aromatic ring in the axial site and so display 'HNMR spectra typical of type b compounds. Two products wereindeed obtained, [Ru(q3:q3-CloH16)C1(NC9H60)] 8a, 8balthough, presumably due to the relatively unhindered nature ofthe ligand. the isomer ratio was in excess of 20: 1 (in retrospectan unsurprising result given the observation of only a singleisomer of 4 arising from reaction with the neutral ligand). Themononuclear nature of these materials was confirmed by a FABmass spectrum. The 'H NMR spectra of both materialsdisplayed the expected four-line patterns for the terminal allylprotons [S 4.34,3.98,3.87 and 2.70 (major isomer 8a); 4.87,4.58,4.02 and 3.09 (minor isomer Sb)] which are qualitatively similarto those of type b complexes.The signals attributed to theinternal ally1 protons occurred as sharp resonances stronglyresembling those observed for the cationic bipyridine andphenanthroline complexes.' ' Logically, and by analogy with4a, 4b, the major product will be of the N-equatorial, 0-axialtype. Evidence for this comes from the consistent upfield shift ofthe signals due to the allyl protons of the major isomer relativeto the minor one, presumably as a consequence of the closerproximity of the aromatic ring to the bis(ally1) ligand when thepyridyl fragment occupies the axial site.Reaction of compound 1 with a-pyrrolidinone, HNC4H60,also gives rise to an axial and an equatorial isomer, related to5-7, namely [Ru(q3:q3-CloH,,)CI(NC4H,O)] 9a, 9b.Thesolid-state infrared spectrum of 9 displays strong, broad peaksat 1540 and 1407 cm-' (signals due to individual isomers notresolved) corresponding to the antisymmetric and symmetricv ( 0 C N ) modes [in this particular case the assignment may bemade with confidence due to the absence of pyridyl v(C=C)bands]. The ' H NMR data are in Table I . The major product(present in a ratio of approximately 5:2) displays a pattern offour terminal ally1 proton resonances characteristic of anequatorial isomer.The relatively abundant minor isomerexhibits a spectrum similar to those of complexes of type b,although in the absence of an aromatic ring the distinction isless obvious. Clearly isomerism in 9 is unlikely to be aconsequence of unfavourable steric interactions between thechloride ligand and bulky ortho ring substituents which areabsent in this case. The formation of substantial quantities ofthe axial isomer is rather attributed to the stereochemical non-rigidity of the saturated five-membered ring of the hydroxy-pyrrolidinate ligand which allows the relief of otherwiseunfavourable steric interactions between the co-ordinatedligands.Reactions with Pyridine-2-thiols.-Sterically hindered lig-ands such as 6-chloro-2-hydroxypyridine, 2-hydroxy-4-methyl-quinoline and 2-hydroxy-6-methylpyridine are often observedto bridge across two metal centres 2' rather than form strainedfour-membered chelate rings.Nevertheless we have describedabove how the reaction of compound 1 with these ligands leadsto the formation of mononuclear complexes 5-7. We reasonedthough that reaction of 1 with ligands containing larger donoratoms such as sulfur, as well as a sterically hindering orthosubstituent, might lead to the formation of bridged, binuclearcomplexes. It should be noted however that pyridine-2-thiol hasalready been observed to form a mononuclear compound onreaction with 1,5 this mode of co-ordination being attributed tothe slowness of the deprotonation step relative to the rate of co-ordination of the ligand in a monodentate fashion uiu thepyridyl nitrogen atom.5We have now investigated the reaction of the more hinderedpyridinethiols, quinoline-2-thiol and 6-methylpyridine-2-thioland of their sodium salts with compound 1 in an attempt toprepare binuciear species.The reactions involving the freeligands gave only mononuclear bridge-cleaved species [Ru-(q3: q3-c10H16)C12(NC9H6SH)] 10 and [Ru(q3: q3-cloHl6)-Cl,(NC,H,MeSH)] 11 in which the ligands are probably co-ordinated in a monodentate fashion via the pyridyl nitrogenatom, by analogy with [ R U ( ~ ~ : ~ ~ - C ~ ~ H ~ ~ ) C ~ ( N ~ and [Ru(q3 :q3-C10H16)C1(NC5H4S)].5 The infrared spectra(Nujol) of both of these complexes display several strong bandsin the region 160&1400 cm-' corresponding to v(C=C) andv(C=N) ring modes, and v(RuC1) bands are observed at 316,289 and 317, 297 cm-' for 10 and 11 respectively.No bandsunambiguously assignable to v(SH) or v(NH) were seen, as wasthe case in Toerien and van Rooyen's study.' Reaction of 1with the preformed sodium salt of quinoline-2-thiol led to aspecies displaying a 'H NMR spectrum containing a four-linepattern for the terminal allyl protons (6 5.00, 4.57, 4.19 and3.14), which was difficult unambiguously to assign to eitheraxial or equatorial co-ordination but consistent with the chelatecomplex [Ru(q3 :q3-CloH16)CI(NC9H6S)] 12a.The internalallyl resonances, which consist of two narrow multiplets,occurring at 6 4.88 and 4.06, imply equatorial co-ordination.The solid-state infrared spectrum of 12a (KBr disc) displayssimilar bands to 10 at 1608, 1589, 1498 and 1421 cm-'. Inaddition, two bands of medium intensity are observed at 1545and 1448 cm-' and are tentatively assigned to v(S-C=N). TheNujol spectrum displays v(RuC1) 303 cm-' and the FAB massspectrum exhibits a strong molecular ion peak at mi: 433along with fragmentation peaks consistent with the proposedstructure. A quantity of a second isomer 12b was also observed(12a: 12b 5 : 1). A single-crystal X-ray structure determination(Fig. 2) revealed a complex possessing an equatorial struc-ture, very similar to that of 5a and [RU(q3:~3-C10H16)C1-(N ,C7H 5S)].5 Low-temperature dissolution of the crystallinesample and simultaneous recording of its 'H NMR spectrumshowed this structure to represent 12a, the form stronglypredominant in solution.The relationship between the mode of ligand co-ordinationand the 'H NMR spectral pattern is less well defined forthe pyridinethiolate complexes than it was for hydroxy-pyridinates, especially in terms of the positions of theterminal allyl resonances {the anomaly is, to some extent,shared by the pyridine-2-thiolate complex [Ru( q 3 : q '-C 6)-Cl(NCsH4S)]') to the extent that it is not possible un-ambiguously to assign structure for a given isomer in isolation2770fiC(10)J. CHEM.SOC. DALTON TRANS.1992Table 3 Fractional atomic coordinates ( x lo4) for [Ru(q3:q3-c,,H,,)c~(Nc,H,s)I 12aFig. 1611 5a showing the atom numbering scheme adoptedMolecular structure of [RU(~~:~~-C,,H,,)C~(NC,H~(~)C~-C(10)Fig. 2showing the atom numbering scheme adoptedMolecular structure of [Ru(q3: q3-CloH,,)Cl(NC9H,S)] 12aTable 2 Fractional atomic coordinates ( x lo4) for [Ru(q3:q3-C , ,H , ,)Cl{NC,H3(0)Cl-6)] 5aX1896( 1)2024(3)W 6 )- 1071(6)1224(11)800( 10)1904(12)3572( 15)4938( 12)4596( 10)4638( 13)3977( 10)11 13(14)5103( 19)- 608( 10)- 924( 13)- 1843( 13)- 1728( 18)- 7 10( 18)202( 17)4'37985845( 2)59 17(4)3826( 12)221 l(7)3783( 15)3695( 12)2728(8)2528( 12)3403( 10)3930( 12)3283( 10)3926( 14)4573( 11)2038( 12)4446( 12)394 l(25)2740( 19)2108( 13)2650( 11)5763(1)5592(2)7002(2)6687(4)6259(4)461 5(4)4757(6)4566(6)5312(5)5981(6)6 5 96( 4)4045(6)6050( 7)7145(6)7705(6)7782( 7)7319(6)6744(6)5 139(4)4347(5)A comparison of the spectra of two isomers of the samecompound may however provide a worthwhile indication as tothe likely geometry.Reaction of compound 1 with the sodium salt of 6-methylpyridine-2-thiol also led to mononuclear species (FABmass spectrum, molecular ion m/z 397), [ Ru(q3 : q3-C ,H 6 ) -CI(NC,H,(S)Me-611 (13a, 13b; ratio 1 : 3), directly analogousto 7a, 7b.Isomer Ratios.-If a model invoking two sets of competingsteric interactions (i) between axial ligand fragments andAtom s2539( 1)! 60 l(2)371 7(2)2364(5)619(7)936(7)1 0 14(6)! 51 7(8)297 3 (8)3727(7)4069( 6)4567(7)1208(9)3841(8)1892(6)1653(8)! 894(8)2342(7)2 5 5 5( 9)2954( 10)31 55(8)2959(8)256 1 (7)1'842( 1)1 2 ! 2(2)- 1 13(2)-601(4)21 l(6)! 167(6)206 1 (6)3 168(6)3!44(6)2 185( 5 )21 02(6)1 lOl(6)1233(7)2997(6)- 144(6)- 696(6)- I765(7)- 2304(6)-3421(7)- 3910(7)- 33237)-2217(6)- 1715(5)2926( 1)4190(1)1950( 1)3765(4)1946( 5 )155 l(5)2170(5)20 1 6( 6)201 6(5)2593(5)361 8(5)4@33(6)580( 5 )423 9(6)4435(4)5195(5)5265(5)4565( 6)4580(7)3892(8)3 136(7)3092(6)380 1 ( 5 )Table 4 Selected bond lengths (A) and angles (") for compound 5aRu-Cl( 1) 2.38 l(3)Ru-0 2.099(8)Ru-N 2.166(6)0-C( 15) 1.278( 14)N-C( 15) 1.361( 18)C1(2)-C( 1 1) 1.71 8( 15)C1( 1)-Ru-N 96.4(4)Cl(l)-Ru-O !58.1(2)N-Ru-0 6 1.9(4)Ru-C( 1) 2.219(8)Ru-C( 2) 2.239(8)Ru-C(3) 2.195(10)Ru-C(6) 2.222(8)Ru-C(8) 2.1 93( 8)Ru-C(7) 2.21 I( 10)Ru-O-C( 15) 95.6(7)Ru-N-C( 15) 90.2(7)N-C( 15kO 1 12.4( 10)Table 5 Selected bond lengths (A) and angles (") for compound 12aRU-Cl 2.461(2)R U-S 2.3 86( 2)Ru-N 2.22 l(5)s-C( 11) 1.74 l(7)N-C( 11) 1.35 l(9)Cl-Ru-N 93.7(2)Cl-RU-S 1 60.0( I )N-Ru-S 67.0(2)Ru-C( 1) 2.209(6)Ru-C(2) 2.206( 6)Ru-C(3) 2.229( 6)Ru-C(6) 2.23 l(7)Ru-C(7) 2.245( 6)Ru-C(8) 2.22 5( 7)Ru-S-C( 1 1) 83.2(3)N-C( 1l)-S 110.2(5)Ru-N-C( 11) 99.5(4)dimethyloctadienediyl methyl substituents and (ii) betweenortho-pyridyl substituents and axial chloride ligands is assumedit becomes possible to rationalise the preferences in isomerratio. The unsubstituted 2-hydroxypyridinate and pyridine-2-thiolate ligands display uniquely equatorial pyridyl co-ordination (type a).When bulky ring substituents are intro-duced ortho to the pyridyl nitrogen atom ( e g . complexes 5 7 )the interactions of these substituents with the axial chlorideligands destabilise the type a form relative to b and thus twoisomers are observed. The axial (type b) form would thus beexpected to become more predominant as the size of the ringsubstituent increases. This argument is qualitatively compatiblewith the observed isomer ratios for complexes 4-7.In the case of 13a, 13b the isomer ratio was observed to be1 : 3, i.e.for 13 it is the Naxial (type b) form which predominates.Evidence for this comes from the allyl region of the 'H NMRspectra of 7 and 13. The terminal allyl signals for the niqjorisomer in the spectrum of 13 display a grouping characteristic oJ . CHEM. SOC. DALTON TRANS. 1992 277 1an axial isomer with three signals between 6 4.5 and 5 and theother one shifted upfield to 6 3.88 (cf: 7b, 6 5.10, 4.77,4.51 and3.70). The signals for the minor isomer are much more evenlydistributed(64.91,4.45,4.15and3.10;cf7a,5.21,4.31,4.30and2.91). Turning to the internal allyl proton resonances, 4a, 5aand 7a (equatorial isomers) display poorly resolved, singlet-likemultiplets (6 4.19 and 3.46, 4 4.32 and 3.59 ppm, 5a; 4.37 and3.56,7a) as does the minor product in the case of 13 (6 4.79 and3.96), although the actual values are shifted downfield by 0.5ppm (an observation consistent with most of the other signalson moving to the sulfur donor atom of the pyridinethiolateligand).In contrast the corresponding signals for 5b and 7boccur as a sharp triplet and sharp, five-line multiplet pair (6 4.81and 4.56, 5b; 4.61 and 4.14, 7b) as do the correspondingresonances for the major isomer in the case of 13, again with anoverall downfield chemical shift ( 6 5.02 and 4.66).Complete proof of these deductions on the identity of 13a,13b must await a single-crystal X-ray structure determinationand concomitant low-temperature NMR experiment, but theevidence would seem to point towards a consistent relationshipbetween equatorial : axial isomer ratio and the relative mag-nitudes of the various steric interactions.X - Raj' Structure Determinations.-The crystal structures ofcompounds 5a and 12a are shown in Figs.1 and 2, and fractionalatomic coordinates and selected bond lengths and angles aregiven in Tables 2 and 3, and, 4 and 5. The details of the struc-ture solutions and refinement are in the Experimental section.As observed in previous structures containing the '(q3 :q3-Cl OH 1 6 ) R U ' Unit 2'4-6'8'1 the geometry about the rutheniumions in both 5a and 12a is conveniently described as a dis-torted trigonal bipyramid, although a pentagonal-bipyramidaldescription can also be justified in this type of bis(a1lyl)-ruthenium(1v) system.22 The 2,7-dimethylocta-2,6-diene-l,8-diyl ligand shows the usual local C2 symmetry and there is nosignificant variation in the Ru-C distances.The rutheniumchloride distances in 5a and 12a are 2.381(3) and 2.461(2) Arespectively. The former is similar to that observed forRu-Cl,,,,,,,, (2.386 A) in the parent chloro-bridged dimer butrather shorter than the norm for other (q3:q3-C,,H,,)R~systems (2.40-2.42 It is similar to that observed in [Ru-(r16-C6H,)Cl(NC,H3(0)Me-6)1 l 2 [2.392(2) A]. The longerRu-Cl bond in 12a may be attributed to the trans effect of thesulfur donor atom. The ruthenium-oxygen distance is rathershort in 5a [2.099(8) when compared to 2.120(5) l 2 and 2.153(6)A l 4 in related ruthenium(I1) arene systems] whereas theruthenium -nitrogen distance is somewhat longer [2.166(6) asagainst 2.091(5) * and 2.084(7) A].'" In general the structure of5a is closely related to that of [Ru(q6-C6H6)C1(NC,H3(o)Me-6)] " with one important difference.In the latter structure theortho-methyl group possesses apparently little stereochemicalconsequence and resides on the opposite side of the molecule tothe chloride ligand. The more sterically demanding nature ofthe bis(al1yl) ligand in 5a causes the chloride ligand and theo-chloride ring substituent to lie virtually eclipsed with oneanother (the pyridyl ring is inclined at 6.2" to the planecontaining the chlorine, nitrogen and oxygen atoms), thechlorine-chlorine non-bonded distance being 3.48( 1) A.As aresult the Ru-N-C(11) angle is opened up to 149(1)", comparedto 143.4(5) in the case of 3 l 2 and 124(1)' when the 2-hydroxy-6-methylpyridinate ion is in the less sterically demandingbridging mode,21 and is indicative of significant strain in thecomplex. Steric strain in the complex is also apparent in the verylarge Cl( 1 )-Ru-N angle 96.4(4)". In undistorted structuresthis angle averages ca. 85" ' 9 " and indeed the CI-Ru-S anglein [{RU(~~:~~-C~~H,~)C~(~-SCN))~] 2o is only 80.3(1)".Values of 88.6(3)" in [RU(~~:~~-C~~H~~)C~(N~C,H,S)] ' and90.3(1) in [(R~(q~:q~-C~~H~~)C1~)~(p-dpprn)] [dppm = bis-(dipheny1phosphino)methanel have been found.The steric strain in this complex is a significant contributoryfactor in the observation of appreciable quantities of the axialisomer 5b, where no strong chlorinexhlorine interactionswould be apparent.However, resulting steric interactionsbetween the bis(a1lyl) ligand and the chloride substituent in 5bmean that 5a is still the predominant isomer observed.For compound 12a the Ru-S distance [2.386(2) A] is sig-nificantly shorter than the equivalent distances in [Ru(q3 :q3-Cl0Hl6)C~(N2C,H5S)],~ [2.425(4) A] and in [{Ru(q3:q3-CloH16)Cl(p-SCN))2] [2.490(4) A] (where the sulfur atomoccupies the equatorial site). In the former case a geometricalfactor may be involved since the sulfur atom in 12a is attachedto a six-membered ring, as opposed to a five-membered one inthe N2C7H,S complex. This is also reflected in the angleC1-Ru-S which is opened out to 160.0(1)c' compared to156.4(1)" in [RU(~~:~~-C,,H,~)C~(N~C~H~S)].~ The ruthen-ium-nitrogen distance, 2.221(5) A, is remarkably long whencompared to the bond lengths noted above (2.09-2.16 A) andprobably, like the long Ru-Cl distance, is a reflection of thebetter donor properties of the sulfur atom and also perhaps itsgreater bulk.ConclusionIn spite of the use of preformed salts of ligands expected to bringabout bridged, binuclear complexation, only mononuclearspecies have been observed.It has been shown that ligandsrelated to 2-hydroxypyridine show two distinct chelate co-ordination geometries when bound to the 'q3 : q 3-C, ,H 6 R ~ ' V 'moiety. These isomers may be distinguished from one anotherby analysis of the allyl regions of their 'H NMR spectra. Byvariation of the substitution of the ortho site of the ligand andthe donor atoms it is possible selectively to synthesise apredominance of either co-ordination geometry.ExperimentalInstrumental.-The IR spectra were recorded on a PE983grating spectrometer between 4000 and 200 cm-' as either KBrdisks or Nujol mulls on CsI plates, NMR spectra on a VarianVXR4OO spectrometer. Microanalyses were carried out by thedepartmental service at University College London.Massspectra were run by the University of London IntercollegiateResearch Service (ULIRS) at the School of Pharmacy. Allmanipulations were carried out under nitrogen with degassedsolvents using conventional Schlenk-line techniques, althoughno significant air sensitivity of the products was noted.Starting Materials.-The compound [{ Ru(q3 : q3-c10H16)-Cl(p-Cl)),] was prepared by published literature methods 3s*7by prolonged heating of ruthenium trichloride in ethanol in thepresence of a large excess of isoprene. Ruthenium trichloridehydrate was obtained on loan from Johnson Matthey plc andwas purified before use by dissolution in water and boiling todryness. Sodium salts were prepared from reaction of sodiummetal with the relevant ligand in dry tetrahydrofuran (thf), or inthe neat ligand.All other reagents and materials were obtainedfrom the usual commercial sources, with the exception of 6-methylpyridine-2-thiol which was synthesised by the literaturem e t h ~ d .~ ~ , ~ ~Preparatioizs.--[Ru(q : q3-C ,H ,)CI(NC,H,O)] 4. Thecompound [ (Ru(q : q3-c loH, 6)cl(p-c1))2] (0.0970 g, 0.1 57mmol) was dissolved in dichloromethane ( 5 cm3) and 2-hydroxypyridine (0.101 8 g, 1.070 mmol) added. After stirring for5 h the reaction mixture was evaporated to ca. volume and thesolution diluted with hexane ( 5 cm3). The product separated onstanding at cu. 250 K for 1 h and was filtered off and washedwith hexane. Yield: 0.0844 g, 0.230 mmol, 73% (Found: C, 49.70;H, 5.70; Cl, 10.80; N, 4.50. Calc. for Cl,H,,CINORu: C, 49.10;H, 5.50; C1,9.70; N, 3.80%). Infrared: v,,,,(OCN) 1596, v(RuC1)317 cm-'. The product may also be prepared more cleanly, incomparable yield, by suspension of 1 in acetone (5 cm3) an2772 J. CHEM.SOC. DALTON TRANS. 1992addition of sodium 2-hydroxypyridinate. The reaction mixturewas stirred for 5 h during which time it changed from pink toorange and the starting material was taken up into solution. Themixture was filtered over Celite and evaporated to an oil. Thisoil was dissolved in diethyl ether (1 cm3) and layered withhexane (1 cm3) from which the product separated as orangecrystals after 12 h.[Ru(q3 : q3-C1 ,H1 ,)C1{NC5H3(0)C1-6}] 5. The compound[(Ru(~~:~~-C~~H~~)C~(~-C~)}~] (0.0728 g, 0.1 18 mmol) wassuspended in acetone ( 5 cm3) and sodium 6-chloro-2-hydroxypyridinate (0.0366 g, 0.242 mmol) added. The reactionmixture was stirred for 36 h during which time it changed frompink to orange and the starting material was taken up intosolution.The mixture was filtered over Celite and evaporated toan oil. This oil was dissolved in diethyl ether (1 cm3) and layeredwith hexane (1 cm3) from which the product separated as deepred crystals after 12 h. Yield: 0.0452 g, 0.1 13 mmol, 48% (Found:C, 44.85; H, 4.50; N, 3.35. Calc. for CI ,Hl,Cl,NORu: C, 44.90;H, 4.75; N, 3.50%). Infrared: 1589, 1437; v(RuC1) 312 cm-I.[Ru(q3 :q3-CloHl~)C1(NC,H5(0)Me-4)] 6. Following aprocedure analogous to that described for 5 using sodium 2-hydroxy-4-methylquinolinate an orange-yellow powder wasisolated. Yield: 0.104 g, 0.241 mmol, 67% (Found: C, 56.15; H,6.15; N, 2.85. Calc. for C,,H,,ClNORu: C, 55.75; H, 5.60 N,3.250/,). Infrared: 1657, 1600, 1550, 1507, 1465, 1446, 141 6, 1403;v(RuC1) 310 cm '.[Ru(q3 : q 3-C10H 16)Cl( NC,H,(O)Me-611 7.The compound{ Ru(q3: q3-CloH1,)CI(p-CI))21 (0.0920 g, 0.149 mmol) wasdissolved in dichloromethane ( 5 cm3) and 2-hydroxy-6-methylpyridine (0.0325 g, 0.298 mmol) added. The mixture wasstirred with Na,[CO,] (0.05 g, excess) for 24 h during whichtime an orange colouration was observed to form. The reactionmixture was filtered over Celite and the filtrate evaporated toan orange oil. The product was obtained as orange crystalsby recrystallisation from diethyl ether. Yield: 0.083 1 g, 0.21 8mmol, 73% (Found: C, 50.30; H, 5.80; N, 3.55. Calc. forC,,H,,CINORu: C, 50.45; H, 5.80; N, 3.70%). Infrared: 1558,1464; v(RuC1) 322 cm-'. The complex was also synthesised insimilar yield by use of the sodium salt of the ligand in a similarway to that outlined for 4.[Ru(q3 :q3-Cl0Hl6)Cl(NC9H60)] 8.The compound [(Ru-(q3:q3-C10H16)C1(p-C1))2] (0.0744 g, 0.121 mmol) was sus-pended in acetone (5 cm3) and 8-hydroxyquinoline (0.0361 g,0.249 mmol) added. The reaction mixture was stirred for 2 h inthe presence of Na,[CO,] (0.05 g, excess) during which time itchanged from pink to orange and the starting material wastaken up into solution. The mixture was filtered over Celite andevaporated to an oil which was recrystallised from diethyl etherto give an orange product. Yield: 0.0750 g, 0.180 mmol, 74%(Found: C, 54.40; H, 5.65; N, 3.40. Calc. for C,,H,,CINORu: C,54.75; H, 5.30; N, 3.35%). Infrared: 1591, 1562, 1493; v(RuC1)318 cm-I.[Ru(q3: q3-C,oH,6)CI(NC4H60)] 9.The compound [(Ru-(q3:q3-C,0H16)Cl(p-CI))2] (0.1 185 g, 0.192 mmol) was dis-solved in dichloromethane (5 cm3) and x-pyrrolidinone (0.05cm3, 0.6 mmol) added. The mixture was stirred with Na2[C03](0.05 g, excess) for 24 h during which time a dark colouration wasobserved. The reaction mixture was filtered over Celite and thefiltrate evaporated to an oil. The product was obtained asyellow crystals by recrystallisation from diethyl ether. Yield:0.0280 g, 0.078 mmol, 20% (Found: C, 45.85; H, 6.50; N, 4.00.Calc. for C,,H,,CINORu: C, 47.10; H, 6.20; N, 3.9573. Infrared:v(0CN) 1540, 1407; v(RuC1) 313 cm-'.[Ru(q3:q3-CloH,,)Cl,(NC,H,SH)] 10. The compound[ f Ru(q3 : q3-C1 ,H ,)Cl(p-CI)),] (0.1064 g, 0.173 mmol) wassuspended in acetone ( 5 cm3) and quinoline-2-thiol (0.0557 g,0.345 mmol) added.The reaction mixture was stirred for 3 hduring which time it changed from pink to orange and thestarting material was taken up into solution. The mixture wasfiltered and evaporated to ca. volume. Diethyl ether (4 cm3)was added and the product obtained as an orange precipitate.Yield: 0.0870 g, 0.185 mmol, 53% (Found: C, 48.60; H, 4.75; N,2.90. Calc. for CI9H,,CI,NRuS: C, 48.60; H, 4.95; N, 3.00%).Infrared: 1617, 1585; v(RuC1) 289, 316 cm-'.[Ru(q3: q3-CloHl,)C12{ NC,H,(SH)Me-6)] 11. Following aprocedure analogous to that outlined for compound 10 aboveusing 6-methylpyridine-2-thiol over a period of 24 h an orange-brown product was obtained. Yield: 0.0817 g, 0.205 mmol, 88%(Found: C, 43.35; H, 5.05; N, 2.60.Calc. for C1,H2,CI2NRuS:C, 44.30; H, 5.35; N, 3.25%). Infrared: 1612, 1589; v(RuC1) 297,317 cm-'.[Ru(q3: q3-CloHl6)C1(NC,H,S)] 12. Following a procedureanalogous to that described for compound 5 using sodiumquinoline-2-thiolate an orange-brown powder was isolated.Yield: 0.050 g, 0.11 5 mmol, 46% (Found: C, 52.10; H, 5.15; N,3.20. Calc. for C,,H,,CINRuS: C, 52.70; H, 5.10 N, 3.25%).Infrared: v(C=C) 1608, 1589, 1498, 1421; v(S-C=N) 1545, 1448;v(RuC1) 303 cm-'.[Ru(q3:q3-ClOHI6)CI{NC5H3(S)Me-6}] 13. Following aprocedure analogous to that described for compound 5 usingsodium 6-methylpyridine-2-thiolate an orange-brown powderwas isolated. Yield: 0.045 g, 0.124 mmol, 66% (Found: C, 48.50;H, 6.10; N, 2.95.Calc. for C,,H,,CINRuS: C, 48.40; H, 5.60; N,3.50%). Infrared: 1597, 1583, 1545; v(RuC1) 303 cm-I.X - Ray Crystal Structure Determinations.-(i) [Ru(q3 : q3-C ,H ,)CI(NC5H3(0)Cl-6)] 5a. Crystal data. C , 5H &l,-NORu, M = 401.32, orthorhombic, space group Pc2,n, a =7.636(3), b = 11.519(3), c = 18.054(8) A, U = 1588 A3 (byleast-squares refinement of diffractometer angles for 32 auto-matically centred reflections in the range 14 < 26 < 24", h =0.71073 A), F(000) = 808, D, = 1.68 g cmP3, p(Mo-Ka) =13.0 cm-l, 2 = 4. Orange block, 0.35 x 0.20 x 0.20 mm.Data coffection and processing. Nicolet R3mV diffractometerequipped with graphite-monochromated Mo-Ka radiation. Thew 2 6 technique was used to collect a data set ( + h , + k , + f )consisting of 17 15 reflections in the range 5 < 28 < 50". Of the1455 unique data 1302 were observed to have I 3 1.50(I) andused in structure solution and refinement.Three standardreflections monitored throughout the data collection showed noappreciable change in intensity. The data were corrected forLorentz and polarisation effects and for absorption, fromadditional azimuthal scan data (maximum, minimum trans-mission 0.903, 0.8 18).Structure solution and rejinement. The structure was solved byconventional direct methods and Fourier difference techniques.Refinement was attempted in the orthorhombic space groupsPcmn and Pc2,n and proceeded most smoothly in the latter,the asymmetric unit being observed to contain one completemolecule. All non-hydrogen atoms were refined anisotropically.Hydrogen atoms were placed in idealised positions with acommon isotropic thermal parameter [r(CH) 0.96 A, Uiso 0.08A'].Full-matrix least-squares refinement gave R = 0.0386,R' = 0.0439 in the final cycle from 180 parameters. A weight-ing scheme w1 = u2(F) + 0.003 058F' was applied and themaximum shift/e.s.d. in the final cycle was 0.03. The largestresidual peak was 0.51 e A-3. No short intermolecular contactswere observed.(ii) [Ru(q3:q3-C1,H1,)CI(NC,H,S)] 12a. Crystal data.C,,H,,CINRuS, M = 433.0, monoclinic, space group P2,/c,a = 10.434(3), h = 12.518(2), c = 14.561(4) A, p = 108.30(2)",U = 1805.6 A3 (by least-squares refinement of diffractometerangles for 29 reflections in the range 13 < 26 < 28", h =0.710 73 A), F(000) = 880, D, = 1.59 g ~ m - ~ , p(Mo-Ka) =11.1 cm-', Z = 4.Orange block, 0.50 x 0.40 x 0.25 mm.Data cdlection and rejinement. As described above. A total of349 1 reflections were collected ( + h, + k, f I ) . Of the 3 148 uniquedata 23 14 were observed [ I 3 3o(I)] and employed in structuresolution and refinement. An absorption correction was applied(maximum, minimum transmission 0.955,0.725).Structure anafjsis rind refinement. Direct methods followedby alternating cycles of least-squares refinement and FourierJ . CHEM. soc‘. DALTON TRANS. 1992 2773difference analysis. Non-hydrogen atoms anisotropic. Hydro-gen atoms were placed in idealised positions, r(CH) 0.96 A, anda common isotropic thermal parameter, Or,,,, refined to 0.090(6)A’.Full-matrix least-squares refinement gave R = 0.0435,R’ = 0.0503 in the final cycle from 209 parameters. A weightingscheme of w’ = 0 2 ( F ) + 0.003 564F2 was applied and themaximum shift/e.s.d. in the final cycle was 0.06. The largestresidual peak was 0.90 e A-3 associated with the rutheniumatom.All calculations were carried out using the SHELXTLPLUS 2 s program package on a MicroVax I1 computer.Additional material for both structures available from theCambridge Crystallographic Data Centre comprises H-atomcoordinates, thermal parameters and remaining bond lengthsand angles.AcknowledgementsWe thank Johnson Matthey plc for generous loans of rutheniumtrichloride and the SERC for a studentship (to J. W. S.) and forprovision of the X-ray diffractometer. Grateful acknowledge-ment is also given to the ULIRS mass spectrometry service atthe School of Pharmacy.References1 D. N. Cox, R. W. H. Small and R. Roulet, J. Chem. Soc., Dalton2 S. 0. Sommerer and G. J. Palenik, Organometallics, 1991, 10, 1203.3 D. N. Cox and R. Roulet, Inorg. Chem., 1990,29, 1360.4 J. W. Steed and D. A. Tocher, J. Organornet. Chem., 1991,412, C34.5 J. G. Toerien and P. H. van Rooyen, J. Chem. Soc., Dalton Trans.,6 J. G. Toerien and P. H. van Rooyen, J. Chem. Soc., Dalton Trans.,Truns., 1991, 2013.1991, 1563.1991,2693.7 L. Porri, M. C. Gallazzi, A. Colombo and G. Allegra, Tetrahedron8 A. Colombo and G. Allegra, Acfa Crystallogr., Sect. B, 1971,27, 1653.9 A. J. Deeming, M. N. Meah, P. A. Bates and M. B. Hursthouse. Znorg.Chim. Acta, 1988, 142, 37.10 E. Block, G. Ofori-Okai, H. Kang and J. A. Zubieta, Znorg. Chim.Acta, 1991, 187, 59.11 M. A. Bennett and A. K. Smith, J . Chem. Soc., Daltori Trans., 1974,233.12 E. C. Morrison, C. A. Palmer and D. A. Tocher, J . Orgunomst. Chem.,1988,349,405.13 D. A. Tocher, R. 0. Gould, T. A. Stephenson, M. A. Bennett, J. P.Ennett, T. W. Matheson, L. Sawyer and V. K. Shah. J. Chem. Soc.,Dalton Trans., 1983, 1571.14 P. Lahuerta, J. Latorre, M. Sanau, F. A. Cotton and W. Schwotzer,Polyhedron, 1988,7, 131 I.15 J. W. Steed and D. A. Tocher, Inorg. Chim. Acta, 1991,191. 29.16 R. A. Head, J. F. Nixon, J. R. Swain and C. M. Woodard, J.17 C. J. Pouchert (Editor), Aldrich Library qf’lnjrared Spectra. 3rd edn.,18 J. W. Steed and D. A. Tocher, Inorg. Chim. Acla, 1991,189, 135.19 J. W. Steed and D. A. Tocher, J . Chem. Soc., Dalton Trans., 1992,459.20 J. W. Steed and D. A. Tocher, unpublished work.21 A. R. Chakravarty, F. A. Cotton and D. A. Tocher, Znorg. Chem.,1985,24,2857.22 J. E. Lydon, J. K. Nicholson, B. L. Shaw and M. R. Truter, Proc.Chem. Soc., 1964,421; J. E. Lydon and M. R. Truter, J. Chem. Soc. A,1968,362.LRtt., 1965, 47,4 187.Organomet. Chem., 1974,76, 393.1981.23 J. Renault, Bull. Soc. Chim. Fr., 1953, 1001.24 H. L. Yale, in Pyridine and its Derivatives, ed. E. Klingsberger,Interscience, New York, 1964, part 4.25 G. M. Sheldrick, SHELXTL PLUS, an integrated system for refiningand displaying crystal structures from diffraction data, University ofGottingen, 1986.Received 14th May 1992; Paper 2/02505

ISSN:1477-9226    

DOI:10.1039/DT9920002765

出版商:RSC    

年代:1992

数据来源: RSC