DALTON FULL PAPER J. Chem. Soc., Dalton Trans., 1998, 3199–3208 3199 The first alkynethiolate derivatives of bis(substituted cyclopentadienyl) titanium(IV) and their role in the synthesis of heterobimetallic compounds. Crystal structures of [Ti(Á5-C5H4SiMe3)2(SC]] CBut)2] and [(Á5-C5H4SiMe3)(SC]] CBut)Ti(Ï-Á5 :Í-P-C5H4PPh2)(Ï-SC]] CBut)- Pt(C6F5)2] † Irene Ara,a Esther Delgado,*b Juan Forniés,a Elisa Hernández, Elena Lalinde,*c Noelia Mansilla b and M.Teresa Moreno c a Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, Spain b Departamento de Química Inorgánica, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain. E-mail: esther.delgado@aumam.es c Departamento de Química, Universidad de la Rioja, 26001 Logroño, Spain Received 20th May 1998, Accepted 13th July 1998 The first thioalkyne derivatives of functionalised titanocene of formula [Ti(h5-C5H4R9)(h5-C5H4R0)(SC]] ] CR)2] (R = But, R9 = R0 = SiMe3 1a; R = Ph, R9 = R0 = SiMe3 1b; R = But, R9 = SiMe3, R0 = PPh2 2a; R = But, R9 = R0 = PPh2 3a) have been prepared by reaction of [Ti(h5-C5H4R9)(h5-C5H4R0)Cl2] and LiSC]] ] CR in diethyl ether.Complexes 1a and 2a have been used as precursors in the synthesis of Ti–M (M = d6 or d8 metal) heteronuclear complexes showing diVerent co-ordination modes. All compounds have been characterised by elemental analysis and 1H, 31P, 19F and 13C NMR and infrared spectroscopy. The crystal structures of two complexes have been solved.Introduction The synthesis and study of early–late heterobimetallic compounds is an active subject of research in organometallic chemistry.1 One of the reasons for this interest is related to some catalytic processes in view of the potential of this type of compound to promote activation of small molecules (e.g. CO).2 Owing to the propensity of sulfur to form M(m-SR)M9 bridges, an appropriate synthetic pathway to such species consists on the use of thiolate derivatives of group 4 metallocenes as metalloligands.Stephan and co-workers 3 have made an important contribution in this area by using diVerent thiolate derivatives of titanocene in their reactions with d10 transition metal species. In the last years we have studied the reactions between d6 and d8 metal fragments and [Ti(h5-C5H4R)2(SR9)2] (R = H, SiMe3 or PPh2; R9 = aryl or alkyl group), yielding bi- and tri-nuclear compounds stabilised by double homo (m-h5 :k-P-C5H4PPh2)2 and (m-SR)2 or hetero (m-h5 :k-PC5H4PPh2)( m-SR) bridging systems.4 On the other hand, the ability of alkynyl ligands to bind several metal centres through s and p bonds is now firmly established.5 In particular in this area we and others have also reported the synthesis of diVerent early–late binuclear doubly alkynyl bridged complexes.6,8 These complexes have been studied in order to gain understanding of the factors that govern the preferred geometries of the C]] ] C groups because of their relevance in C–C coupling alkynide processes,7 as well as C–C bond cleavage on butadiynes.8 By contrast with the amount of work devoted to thiolate and alkynide bridged heterobimetallics and their mononuclear precursors, reports on related alkynethiolates are exceedingly rare.Interestingly the few examples that have been published show a quite versatile co-ordination behaviour (Scheme 1). For † Dedicated to Professor Pascual Royo on the occasion of his 60th birthday.instance, Weigand et al. have reported 9 not only the syntheses of several alkyne thiolate mononuclear complexes of RuII and PtII with these ligands acting as h1-(S) bonded ligands (M–SC]] ] CR9), but also the ability of the phenylalkynethiolate to act as an h1-(C) bonded thioketenyl, [Ru]]] C(Ph)–C]] S, terminal group.9a Recently, the co-ordination as an alkyne thioketenyl h2-(C,C) with the ligand acting as a three electron donor has been also demonstrated,10 but, as far as we are aware, only a diiron carbonyl complex [Fe2(CO)6(m-C]] ] CPh)(m-SC]] ] CPh)] containing a sulfur alkynethiolate bridging group m-(S,S) has been reported.11 In the context of these groups it should be noted Scheme 1 M S C C R M S C C Ph M S C C Ph h1-( S) h1-( C) h2-( C, C) M C S C M' m-( S,S) R M = Pt, Ru Ru Mo, W Fe3200 J.Chem. Soc., Dalton Trans., 1998, 3199–3208 that some additional work has been developed with the isomeric thioacetylide ligands C]] ] CSR.12 In this paper we report on the preparation and properties of several mononuclear alkynethiolate titanocene complexes [Ti(C5H4R9)(C5H4R0)(SC]] ] CR)2] 1–3 and describe their reactivity towards several d6 [Mo(CO)4(nbd)] and [Mo(CO)3- (NCMe)3] and d8 cis-[M(C6F5)2(thf)2] (M = Pt or Pd) metal complexes containing labile ligands.The syntheses of homo bis(m-alkynethiolate) 4a–6b and hetero bis(m-alkynethiolate, m-cyclopentadienyldiphenylphosphine) bridged derivatives 7, 8, 9 and the solid-state structures of [Ti(h5-C5H4SiMe3)2(SC]] ] CBut)2] 1a and [(h5-C5H4SiMe3)(SC]] ] CBut)Ti(m-h5 :k-P-C5H4- PPh2)(m-SC]] ] CBut)Pt(C6F5)2] 8 are presented.Results and discussion Mononuclear derivatives The formation of metallocene alkynethiolate titanium(IV) derivatives [Ti(h5-C5H4R9)(h5-C5H4R0)(SC]] ] CR)2] 1a–3a was accomplished by treatment of [Ti(h5-C5H4R9)(h5-C5H4R0)Cl2] (R9 = R0 = SiMe3; R9 = SiMe3, R0 = PPh2, R9 = R0 = PPh2) with lithium alkynethiolate reagents LiSC]] ] CR13 (2 equivalents) at very low temperature (270 8C) in diethyl ether [eqn. (1)].After conventional work-up complexes 1–3 were isolated as green microcrystalline solids and their spectroscopic (IR, 1H, 13C and 31P NMR) and analytical data unequivocally confirm the structural proposal shown in eqn. (1) with the alkynethiolate ligands h1-(S) bonded. Further confirmation was obtained from the X-ray diVraction study of compound 1a.It should be noted that initial attempts to carry out the former reaction at room temperature, following similar reaction conditions to those reported for ruthenium(II) and platinum(II) complexes,9 failed to yield the alkynethiolate derivatives. The substitution of SiMe3 by PPh2 groups on the cyclopentadienyl rings reduces considerably the stability of these systems.Thus, whereas complexes 1a,1b and 2a show satisfactory elemental analysis, the instability of 3a in solution and in the solid state precludes a good analysis. In the same line we have previously shown that the stability of mixed [Ti(h5-C5- H4SiMe3)(h5-C5H4PPh2)X2] (X = Cl or SPh) derivatives is considerably higher than that of analogous [Ti(h5-C5H4PPh2)2X2].14 The most noticeable fact in the IR spectra of complexes 1–3 is the presence of a weak absorption in the 2129–2145 cm21 region corresponding to the C]] ] C stretching mode, clearly indicating that the acetylenic fragments are not involved in co-ordination.Their NMR data (1H and 13C) indicate that only one of the two expected isomers (syn or anti) is present in solution (see Experimental section).In the 1H NMR spectra the resonances due to cyclopentadienyl protons, two for 1a, 1b and 3a (d 6.40–6.62, 6.01–6.53) and four for complex 2a (6.54, 6.38, 6.34, 6.11) due to the presence of two diVerent substituted rings, are shifted upfield in relation to the dichloride starting precursors. This eVect can be accounted for the lowering in the electronegativity on going from the chloride to the alkynethiolate ligand.As expected, singlet signals are observed for the But or SiMe3 groups in all complexes. The presence of these groups is also confirmed by their characteristic 13C NMR Ti Cl Cl R' R'' RC CSLi Ti R' R'' 1a SiMe3 SiMe3 But 1b SiMe3 SiMe3 Ph 2a SiMe3 PPh2 But 3a PPh2 PPh2 But + -70 oC Et2O R' R" R SC CR SC CR (1) 2 resonances which appear in the expected range.Particularly evident are the acetylenic carbon resonances (d 80.8, 117.5 1a; 93.0, 107.3 1b; 80.2, 117.8 2a) which occur in a similar region to that previously reported for other h1-(S) bonded alkynethiolate (M–SC]] ] CR)9 or alkynyl (M–C]] ] CR)6,8 compounds. Complexes 1a and 1b show only three cyclopentadienyl carbon resonances while the mixed derivative [Ti(h5-C5H4SiMe3)- (h5-C5H4PPh2)(SC]] ] CBut)2] 2a exhibits five resonances for each substituted C5H4 ring suggesting that the five carbon atoms are inequivalent probably due to molecular steric strains.The shielding of the 31P resonances displayed by complexes 2a (d 215.2) and 3a (d 215.5) is typical of this type of compound.4a Crystal structure of [Ti(Á5-C5H4SiMe3)2(SC]] ] CBut)2] 1a This compound crystallises with two crystallographically independent molecules, which have essentially the same structure, in the asymmetric unit.Discussion will therefore be limited to only one of them. The monomeric structure of 1a is shown in Fig. 1 and selected bond distances and angles are listed in Table 1. The compound shows a distorted tetrahedral arrangement around the titanium atom made up of the two centroids of trimethylsilylcyclopentadienyl rings, which adopt a staggered disposition, and the two thiolate ligands.The S(1)–Ti(1)–S(2) angle of 92.30(13)8 as well as the Ti(1)–S(1,2) [2.451(4) Å], Ti(1)–centroid(1) [2.050(2) Å] and Ti(1)–centroid(2) [2.038(3) Å] distances are in the range reported for analogous compounds [Ti{h5-C5H4P(S)Ph2}2- (SPh)2],14b [Ti(h5-C5H4SiMe3)2(SC6F5)2] 14a and [Ti(h5-C5H5)2- (SMe)2].3e Once again the endo (anti) conformation shown by this titanium(IV) derivative confirms the relationship between the type of isomer and the S(1)–Ti–S(2) angle.The bond lengths S–C [1.688(11), 1.712(12) Å] and C]] ] C [1.174(13), 1.144(14) Å] and angles Ti–S–C [107.4(7), 114.2(3)], S–C–C [177.5(12), 174.0(12)] and C–C–C [173.3(13), 169(2)] found Fig. 1 View of molecular structure of [Ti(h5-C5H4SiMe3)2(SC]] ] CBut)2] 1a. Table 1 Selected bond lengths (Å) and angles (8) of complex 1a (molecule 1) Ti(1)–S(1) Ti(1)–S(2) S(1)–C(17) S(2)–C(23) S(2)–Ti(1)–S(1) cent(1)–Ti(1)–cent(2) S(2)–C(23)–C(24) Ti(1)–S(1)–C(17) 2.451(4) 2.451(4) 1.688(11) 1.712(12) 92.30(13) 130.9 174.0(13) 107.7(4) C(17)–C(18) C(23)–C(24) Ti(1)–cent(1) Ti(1)–cent(2) S(1)–C(17)–C(18) C(17)–C(18)–C(19) C(23)–C(24)–C(25) Ti(1)–S(2)–C(23) 1.174(13) 1.144(14) 2.050 2.038 177.5(12) 173.3(13) 169(2) 114.2(3)J.Chem. Soc., Dalton Trans., 1998, 3199–3208 3201 within the alkynethiolate fragments show no unusual features, being quite similar to those found in complexes [Pt(PPh3)2- {SC]] ] CC(Me)}2] 9b and [Fe2(CO)6(m-C]] ] CPh)(m-SC]] ] Ph)] 11 which to our knowledge are the only examples of thioalkyne derivatives of transition metals structurally characterised.Heterobinuclear derivatives We have previously shown that titanocene thiolate derivatives [Ti(h5-C5H4R9)2(SR)2] (R9 = H, SiMe3 or PPh2) can act as either bi- [R9 = H or SiMe3(S,S), PPh2(P,P)] or tetra-dentate [R9 = PPh2, bis(P,S) or P,P; S,S] ligands towards the d6 Mo(CO)4 and d8 M(C6F5)2 (M = Pd or Pt) metal fragments.4 The substitution of arene- or alkene-thiolates by alkynethiolates on the mononuclear titanocene supplies an additional co-ordination position.We have reported several examples illustrating the ability of bis(alkynyl) transition metal complexes [M9Ln- (C]] ] CR)2] (M9 = Pt,15a–d Ir 15e or Ti 6a) to bond “cis-M(C6F5)2” (M = Pt or Pd) metal fragments through h2-acetylenic bonding interactions.Therefore, we considered it of interest to explore the reactivity of the novel bis(alkynethiolate) derivatives 1–3 towards the same substrates: [Mo(CO)4(nbd)] and cis- [M(C6F5)2(thf)2] (M = Pt or Pd, thf = tetrahydrofuran), respectively.The results of this study are summarised in Scheme 2. Treatment of [Ti(h5-C5H4SiMe3)2(SC]] ] CR)2] with either [Mo(CO)4(nbd)] (excess) or cis-[M(C6F5)2(thf)2] (1 equivalent) in toluene at room temperature (for 1a and M = Pt in CH2Cl2) results in the formation of neutral bis(thiolato)bridged heterobinuclear complexes [(h5-C5H4SiMe3)2Ti(m-SC]] ] CR)2- MLn] [ MLn = Mo(CO)4 4a, Pt(C6F5)2 5a, 5b, or Pd(C6F5)2 6a, 6b] in moderate to high yield (60% 4a–88% 6b).Complex 4a is isolated as a green solid after chromatographic purification. Complexes 5a (orange) and 6b (red-garnet) are precipitated as solids by treatment of the residues with n-heptane and n-hexane respectively, while 5b and 6a can be isolated as orange solids only by removing the solvent. These latter compounds are extremely soluble even in hydrocarbon solvents such as nhexane, pentane or n-heptane.In spite of many attempts we have not been able to obtain suitable crystals for X-ray analysis of any of these dinuclear compounds 4–6, however their spectroscopic data are consistent with the S,S co-ordination mode of the difunctional metallocene [Ti](SC]] ] CR)2 chelating ligands.Thus, their IR spectra show a medium n(C]] ] C) absorption in the characteristic region of non-co-ordinated alkynes.13b Compared with the precursors (1a 2129 cm21 and 1b 2134 cm21) the stretching frequency n(C]] ] C) for 5 and 6 is shifted to higher wavenumbers (2168 5a, 2165, 5b, 6b; 2166 cm21 6a) suggesting that co-ordination of the sulfur lone pair to platinum or palladium probably reduces sulfur p-donor interactions with the acetylenic fragment.In marked contrast the solution IR spectrum of the Mo–Ti complex 4a shows the n(C]] ] C) at 2072 cm21. The relative lowering of n(C]] ] C) (ª57 cm21) is considerably smaller than those previously reported for coordinated thioalkynes,16 i.e. [S{(h2-C]] ] CPh)Co2(CO)6}2] 16a 1592 vs. S(C]] ] CPh)2 2180 cm21 and [{Cu(O3SCF3)2S(C]] ] CBut)2] 16b 1988 vs.S(C]] ] CBut)2 2200 cm21, suggesting that acetylenic fragments are not co-ordinated to Mo. The NMR data are consistent with the presence of the dinuclear species in the two isomeric forms syn and anti shown in Scheme 2. This structural feature, which arises from the relative orientation of the alkyne groups on the sulfur atoms, is not unusual and in many cases equilibrium studies find the two conformers to be of similar thermodynamic stability.In fact, a few [(h5-C5H5)2Ti(m-SR)2- Mo(CO)4] compounds have been reported as endo (anti/syn) stereochemically non-rigid mixtures in solution.17 We have previously found that the heterobimetallic Ti–Pt and Ti–Pd [(h5-C5H4R9)2Ti(m-SR)2M(C6F5)2] (M = Pt or Pd, R9 = H or SiMe3, R = Ph or C6F5) systems adopt both in the solid state (X-ray; M = Pd, R9 = SiMe3, R = Ph) and in solution an endo (syn) arrangement with respect to the central TiS2M core.4b The higher preference for the anti isomer found for these Ti–M mixed derivatives, related to the ones mentioned before, could be attributed to the bulkiness of the alkyne fragment on these Scheme 2 (i) [Mo(CO)3(NCMe)3], toluene, room temperature (r.t.); (ii) [M(C6F5)2(thf)2] (M = Pt or Pd), toluene, 220 8C; (iii) [Mo(CO)4(nbd)], toluene, r.t.; (iv) [M(C6F5)2(thf)2] (M = Pt or Pd), toluene, r.t.(for 5a, CH2Cl2). Ti R' R'' SC CR SC CR Ti P SiMe3 Mo OC CO CO Ph Ph SC CBut SC CBut S S SiMe3 SiMe3 S S SiMe3 SiMe3 S S SiMe3 SiMe3 Mo CO CO CO CO S S SiMe3 SiMe3 Mo CO CO CO CO Ti P Ph Ph SC CBut SiMe3 SC CBut C6F5 C6F5 C C6F5 M=Pt 8 M=Pd 9 C C6F5 M CR (iii) CR C C M C6F5 Ti (ii) (iv) 4a ratio syn:anti 1:1 7 C (i) C + R M 5:1 ratio syn: anti 5a But 0.9:1 6a But C Pd + Pt 6b Ph Pd CR M 10:1 5b Ph But Ti C C C Pt C 1:1 Ti C CR Ti But But But C6F53202 J.Chem. Soc., Dalton Trans., 1998, 3199–3208 m-SC]] ] CR bridging ligands. Similar steric considerations have previously been suggested to rationalise the shift of the equilibrium in favour of the anti isomer.18 The preference for the syn isomer is slightly higher for the phenyl derivatives 6b and 5b than for the tert-butyl complexes 6a and 5a respectively.The reason for the fact that the syn conformation seems to be more thermodynamically favoured on palladium than platinum mixed-metal complexes is less clear.According to the presence of an ª1:1 syn : anti mixture, the Ti–Mo complex 4a exhibits in its proton spectrum two singlet resonances (d 1.23, 1.20) due to But groups and, at high field, two signals of equal intensity (d 0.44, 0.33) assigned to the nonequivalent SiMe3 groups in the syn isomer and, a more intense signal at d 0.39 which belongs to the equivalent SiMe3 groups in the anti isomer. The expected three distinct cyclopentadienyl sets of resonances are observed slightly upfield shifted (d 6.31– 5.27) with respect to those seen for 1 (d 6.46, 6.38) indicating an increase of electron density on the Ti.This spectroscopic feature has been previously observed in related bis(alkyl) and aryl bridging thiolate Ti–Mo compounds.17 The proton spectrum is temperature dependent.Thus, on raising the temperature all signals broaden, and at 150 8C a single sharp But (d 1.24) and broad SiMe3 (d 0.41) resonances are observed while in the cyclopentadienyl region only two very broad humps are barely discernible suggesting that both isomers are interconverting on the NMR timescale. When the temperature is lowered the high-field region (But, SiMe3 resonances) does not change indicating a similar syn : anti ratio (1.1 : 1) but, however, the signals in the cyclopentadienyl region clearly broaden.In the lowest temperature spectrum (250 8C) ten distinct proton resonances [d 6.30 (2 H), 6.22 (2 H), 6.12, 5.84, 5.67 (1 H each), 5.52 (2 H), 5.26 (4 H), 5.12, 4.88, 4.79 (1 H each)] are seen implying rigid formulations with the lack of a symmetry plane passing through Ti and Mo atoms at low temperature.This fact could be tentatively related to hindrance of the rotation of either the bulky C]] ] CBut groups around the C(sp)–S bonds or the substituted h5-C5H4SiMe3 rings. As was previously found in related aryl (SPh, SC6F5) thiolate syn isomers [(h5-C5H4SiMe3)2Ti(m-SR)2M(C6F5)2] (M = Pt or Pd), the heterobinuclear Ti–Pt complexes 5 are relatively more rigid in solution than the Ti–Pd ones 6.Thus, both titanium– platinum complexes 5 display in their low (250 8C) and room temperature (20 8C) 19F NMR spectra the expected two diVerent sets (AFMRX systems) of rigid C6F5 fluorine resonances (one set assigned to each isomer), and similar spectra, but with a less defined pattern, were also observed at the highest accessible temperature (150 8C).No significant modification of the ratio of both isomers was observed in the range of temperature explored. Similar results were observed from the variable-temperature 1H NMR spectra. Only at high temperature (150 8C) the cyclopentadienyl and SiMe3 (also But groups for 5a) resonances of both isomers become broad (one SiMe3 is observed for 5b but coalescence of C5H4 signals is not reached) suggesting that the rate of interconversion syn–anti is still slow on the NMR timescale.By contrast, the 1H and 19F NMR spectra of the titanium–palladium complexes 6 at 150 8C show the presence of only one set of resonances for the C6F5, C5H4SiMe3 and But groups (this latter in the case of 6a).Selected ranges of the variable temperature 19F (Fortho) and 1H (C5H4SiMe3) spectra of 6b are shown in Figs. 2 and 3. As can be observed when the temperature is lowered the broad Fortho resonance (Fig. 2) is resolved into four distinct resonances with very diVerent 1 : 10 : 10 : 1 ratio. The signals with lower intensity which exhibit higher d(F2), d(F6) values (at 250 8C, 2115.8; 2117.6) are unequivocally assigned to the anti isomer in accordance with the proton data (Fig. 3). The proton spectrum at low temperature (250 8C) clearly reveals the presence of the two non-equivalent C5H4SiMe3 groups, which is consistent with that expected for the syn isomer (major isomer, d 6.81, 6.57, 6.36 and 6.28 CH; d 0.38, 0.22 SiMe3). The remaining signals of lower intensity (d 6.77, 6.45, 6.21 and 5.92 CH; 0.31 SiMe3) are therefore attributed to the anti isomer. When the temperature is increased the signals broaden and, finally, collapse to only two broad ones for the cyclopentadienyl resonances and one signal for the SiMe3 at ca. 150 8C. This pattern suggests fast interconversion of both isomers on the NMR timescale at this high temperature. Similar behaviour was observed for complex 6a, the most remarkable diVerence being the diVerent syn : anti (ª5 : 1) ratio found at low temperature.The 13C NMR spectra of all complexes have also been recorded (5, 6 at 250 8C, due to their low stability in solution, and room temperature for 4a, see Experimental section for data). A syn : anti mixture in approximately the expected ratio is observed for all complexes, particularly, for the SiMe3 and But (5a, 6a) resonances.Unfortunately, they are not very informative in the C]] ] C region. Only for 5b the expected four alkyne carbon resonances which appear slightly upfield shifted in relation to the starting material are clearly identified. For 6b the acetylenic carbon resonances of the major isomer (syn) are also shifted (d 103.5, 81.6 vs. 107.3, 93.0 1b) and, a small signal at d 99.2 can tentatively assigned to the minor anti isomer. For the remaining complexes, only one (4a) or two signals (5a, 6) in the d 67.78–75.5 range can be assigned. According to previous results 4c the preference for coordination through the phosphorus atom is evidenced by using the mixed-ligand mononuclear complex [Ti(h5-C5H4SiMe3)- (h5-C5H4PPh2)(SC]] ] CBut)2] 2a as precursor.Thus (Scheme 2), by treatment of 2a with [Mo(CO)4(nbd)] in toluene, at room temperature, a single heterodimetallic complex 7 was obtained in very low yield (12%). The IR spectrum (toluene solution) of the isolated material showed, in addition to a band at Fig. 2 Variable temperature 19F NMR spectra (Fortho region) of [(h5- C5H4SiMe3)2Ti(m-SC]] ] CPh)2Pd(C6F5)2] 6b (syn and anti).Fig. 3 Proton NMR spectra of the complex [(h5-C5H4SiMe3)2Ti(m- SC]] ] CPh)2Pd(C6F5)2] 6b (syn and anti) at diVerent temperatures.J. Chem. Soc., Dalton Trans., 1998, 3199–3208 3203 2070 cm21 assignable to n(C]] ] C), a clear CO 1956vs, 1895m, 1879s pattern attributable to a fac-Mo(CO)3 unit suggesting that the organometallic 2a fragment is acting as a tridentate (S,S,P) ligand to the Mo.Further evidence follows from the elemental analysis and the spectroscopic properties. Moreover, when [Mo(CO)3(NCMe)3] was used instead of [Mo(CO)4(nbd)] the reaction proceeded, as expected, in a cleaner way and complex [(h5-C5H4SiMe3)Ti(m-h5 :k-P-C5H4PPh2)(m-SC]] ] CBut)2- Mo(CO)3] 7 was obtained in a higher yield (53%).A similar behaviour has recently been observed by us when using related trifunctional ligand systems [Ti(h5-C5H4SiMe3){h5-C5H4P(E)- PPh2}(SPh)2] (E = O or S) and [W(CO)4(nbd)2].19 It seems that the three potential donor atoms (S, S and P) are well suited for the stabilisation of the fac-Mo(CO)3 fragment. The NMR data reveal that only one of the two expected isomers (syn and anti) is present in solution.A syn orientation is tentatively suggested on the basis of the 1H and 13C NMR spectra which display magnetically equivalent SC]] ] CBut ligands. Thus, the 1H NMR spectrum exhibits, in addition to four cyclopentadienyl proton resonances at d 6.23, 5.17 and 5.61, 5.49 assignable to diVerent C5H4PPh2 and C5H4SiMe3 rings, respectively, a single sharp But signal at d 1.20.The SiMe3 protons are observed at d 0.41. A similar pattern was observed in the 250 to 150 8C temperature range, suggesting the absence of any dynamic process. In the 13C NMR spectrum the proposed formulation is mainly supported by the observation of only one set of acetylenic carbon resonances (d 111.4 and 75.4) and a clear singlet signal at d 31.1 due to methyl carbon resonances of the equivalent But groups.Furthermore, in accordance with the P,S,S, coordination suggested, the 31P NMR spectrum shows the phosphorus resonances (d 39.7) strongly shifted to low field (D = 154.9) relative to the starting material (d 215.2 2a). Similarly, as shown in Scheme 2, treatment of complex 2a with 1 equivalent of cis-[M(C6F5)2(thf)2] (M = Pt or Pd) in toluene at low temperature (220 8C) aVords the heterodinuclear derivatives [(h5-C5H4SiMe3)(SC]] ] CBut)Ti(m-h5 :k-P-C5H4PPh2)- (m-SC]] ] CBut)M(C6F5)2] (M = Pt 8 or Pd 9).These complexes, isolated as violet microcrystalline solids, are moderately airstable in the solid state, but in solution they decompose in a few hours. The dimetallic formulation with an heteromixed bridging system is consistent with their spectroscopic data (IR, NMR) and confirmed by an X-ray diVraction study on the Ti–Pt complex 8 (see below).The presence of non-co-ordinated alkyne fragments is inferred from the IR spectra. Thus, both complexes show n(C]] ] C) absorptions assignable to the alkynethiolate ligands which lie approximately in the same region as for the corresponding mononuclear derivative [2157w, 2141m 8; 2158w, 2141m 9 vs. 2145 cm21 2a]. Moreover, co-ordination of the phosphorus atom is evidenced from their 31P NMR spectra, which show a singlet resonance (d 5.14 8, 10.93 9) shifted to higher frequency relative to that of 2a. For both complexes the signal is somewhat broad probably due to unresolved longrange phosphorus–fluorine couplings and, as expected, for 8 the signal is flanked by 195-platinum satellites [1J(Pt–P) = 2361 Hz].The 1H NMR spectra (at 250 8C and at room temperature) exhibit, in addition to phenyl resonances, two singlets at d 1.20, 1.11 for 8 and 1.22, 1.11 for 9 and another singlet at d 0.13 due to the methyl moieties of the inequivalent tertbutylalkynethiolate and free C5H4SiMe3 ligands, respectively.Seven proton signals (one of them with double intensity) are seen in the cyclopentadienyl region indicating magnetically non-equivalent halves on both substituted cyclopentadienyl rings. The 19F NMR spectra are not temperature dependent either, showing the presence of inequivalent C6F5 rings, for which the platinum co-ordination plane is not a mirror plane (AFMRX systems, see Experimental section).A single crystal X-ray structural determination of complex 8 (Fig. 4) confirmed that the mononuclear precursor acts as a P,S bidentate ligand towards the “cis-Pt(C6F5)2” fragment. The complex crystallises together with one molecule of toluene and 0.5 of hexane. Selected bond lengths and angles are collected in Table 2. The titanium atom is pseudo-tetrahedrally surrounded by two cyclopentadienyl ligands and the sulfur atoms of the two SC]] ] CBut ligands.The platinum centre exhibits a distorted “square-planar” geometry formed by the Cipso atoms of two mutually cis C6F5 groups, a sulfur atom of a m-SC]] ] CBut ligand and a phosphorus atom of the bridging C5H4PPh2 group. The centroid(1)–Ti–centroid(2) angle of 133.58 as well as the titanium–centroid distances (2.039 and 2.049 Å) are in the usual range found for related complexes such as [{(Mo(CO)4}2{m-(PPh2C5H4)2Ti(SPh)2}] (2.065 Å) 4e or [(h5-C5H4SiMe3)2Ti(m-SPh)2Pd(C6F5)2] [2.07(2), 2.05(1) Å] 4b with the cyclopentadienyl rings exhibiting an antiperiplanar (staggered) disposition.As was expected the two titanium to sulfur linkages are very diVerent, the shortest corresponding to the unco-ordinated SC]] ] CBut. The bond between the metal to the sulfur of the terminal thioalkyne ligand [Ti–S(2) 2.366(4) Å] is slightly shorter than that observed in 1a [2.451(4) Å] but in the range found for other mononuclear titanocene dithiolates such as [Ti(h5-C5H5)2(SEt)2] [2.398(3) and 2.387(3) Å].20 The other sulfur atom S(1) is bridging between titanium and platinum.The Ti–S(1) bond distance [2.532(4) Å] is substantially longer than the corresponding Pt–S(1) bond length [2.360(3) Å] and both slightly longer than those previously observed in the trimetallic complex [(OC)4Mo(m-PPh2C5H4)2- Ti(m-SPh)2Pt(C6F5)2] 4c [Ti–S 2.305(1), 2.456(2); Pt–S 2.256(1), 2.347(1) Å]. However, these distances lie in the range of those for other thiolate-bridged containing titanium or platinum centres.3,4,21,22 The Pt–P bond distance of 2.277(3) Å (and also the Pt–S) is comparable with that found in [Pt(SC5H9NMe2)( dppe)].22 The S(1)–Ti–S(2) angle of 89.39(12)8 is slightly Fig. 4 Molecular structure of [(h5-C5H4SiMe3)(SC]] ] CBut)Ti(m-h5 :k-PC5H4PPh2)( m-SC]] ] CBut)Pt(C6F5)2] 8. Table 2 Selected bond lengths (Å) and angles (8) for complex 8 Pt–C(7) Pt–P(1) Pt–C(1) Pt–S(1) Ti–S(2) Ti–S(1) Ti ? ? ? Pt C(1)–Pt–P(1) Ti–S(1)–C(38) C(1)–Pt–S(1) C(7)–Pt–S(1) P(1)–Pt–S(1) Pt–S(1)–Ti S(2)–Ti–S(1) Ti–S(2)–C(44) 2.023(13) 2.277(3) 2.039(12) 2.360(3) 2.366(4) 2.532(4) 3.817(3) 175.7(4) 106.6(4) 94.5(3) 178.1(4) 83.92(11) 102.51(12) 89.39(12) 111.1(4) S(1)–C(38) S(2)–C(44) Ti–cent(1) Ti–cent(2) C(38)–C(39) C(44)–C(45) C(39)–C(38)–S(1) C(38)–C(39)–C(40) C(45)–C(44)–S(2) S(1)–Ti–cent(1) S(1)–Ti–cent(2) C(7)–Pt–C(1) C(7)–Pt–P(1) C(44)–C(45)–C(46) 1.700(12) 1.668(12) 2.039 2.049 1.19(2) 1.20(2) 175.3(11) 178.2(13) 179.3(11) 102.0 109.7 87.0(5) 94.6(4) 178.2(13)3204 J.Chem. Soc., Dalton Trans., 1998, 3199–3208 smaller than that seen in 1a [92.30(13)8] and those observed in related mononuclear titanocene bis(thiolate) complexes [Ti(h5-C5H4SiMe3)2(SC6F5)2] [100.6(1)8],14a [Ti(h5-C5H5)2(SR)2] [R = Ph (99.48),23 or Et (93.88) 20] or titanocene thiolate bridged [(h5-C5H4SiMe3)2Ti(m-SPh)2Pd(C6F5)2] 4b [95.7(2)8] complexes. The internal angles at platinum and at bridging sulfur [P(1)–Pt– S(1) 83.92(11)8 acute and Pt–S(1)–Ti 102.51(12)8 obtuse] are in accordance with the very long Pt ? ? ? Ti distance [3.817(3) Å] found.The acetylenic fragments, C]] ] CBut, are located on the same side of the S(1)–Ti(1)–S(2) plane adopting an endo (syn) conformation. Their structural data, C]] ] C bonds [C(38)–C(39) 1.19(2), C(44)–C(45) 1.20(2) Å] and bond angles [S(1)–C(38)– C(39) 175.3(11); C(38)–C(39)–C(40) 178.2(13), S(2)–C(44)– C(45) 179.3(11), C(44)–C(45)–C(46) 178.2(13)8], are in the usual range and deserve no further comment.As was mentioned before, complex [Ti(h5-C5H4PPh2)2- (SC]] ] CBut)2] 3a is very unstable both in the solid state and in solution. In preliminary experiments it was treated with [Mo(CO)4(nbd)] (1 equivalent) in toluene either at room or lower (240 8C) temperature, but unfortunately the reaction failed, giving just decomposition products and, therefore, no more experiments were made with this precursor.In summary, bis(alkynethiolate)titanium complexes [Ti(h5- C5H4R9)(h5-C5H4R0)(SC]] ] CR)2] 1–3 have been prepared from [Ti(h5-C5H4R9)(h5-C5H4R0)Cl2], by using classical metal– halogen exchange reactions with LiSC]] ] CR reagents. In spite of the presence of two potential bifunctionalities, the lone pair at the sulfur atom and the acetylenic moiety on each SC]] ] CR, the mononuclear [Ti(h5-C5H4SiMe3)2(SC]] ] CR)2] (R = But 1a or Ph 1b) complexes serve only as bidentate (S,S) metalloligands when treated with d6 [Mo(CO)4(nbd)] or d8 cis-[M(C6F5)2(thf)2] (M = Pt or Pd) substrates.The co-ordination of the acetylenic fragments cannot be forced even in presence of an excess of these latter reagents, reactions which lead to the same doubly thiolate-bridged early–late heterodimetallic products 4–6 (see Experimental section).The NMR data reveal that in all cases the products are isolated as a syn : anti mixture of isomers with a clear thermodynamic preference for the syn conformation in the palladium mixed-metal complexes (ª1 : 1 for Ti–Mo 4a and Ti–Pt 5 vs. 5:1 6a, 10 : 1 6b). The variable NMR data confirm that both isomers interconvert on the NMR timescale at the highest accessible temperature (150 8C) (4a and 6 fast 5 slow). Similar to previous observations, a favoured co-ordination through phosphine ligands with these late transition metals is evidenced by the fact that the mixed ligand complex [Ti(h5-C5H4SiMe3)(h5-C5H4PPh2)(SC]] ] CBut)2] 2a acts as bidentate P,S when treated with cis-[M(C6F5)2(thf)2] (M = Pt or Pd) yielding 8 and 9, respectively and, as a tridentate organometallic metallo ligand toward [Mo(CO)4(nbd)] or [Mo(CO)3- (NCMe)3], giving [(h5-C5H4SiMe3)Ti(m-h5 :k-P-C5H4PPh2)- (m-SC]] ] CBut)2Mo(CO)3] 7.Experimental Reactions were carried out under an atmosphere of argon by means of conventional Schlenk techniques.24 Solvents were purified according to standard procedures.25 The complexes [Ti(h5-C5H4SiMe3)2Cl2],26 [Ti(h5-C5H4SiMe3)(h5- C5H4PPh2)Cl2],14b [ Ti(h5-C5H4PPh2)2Cl2],27 [ Mo(CO)4(nbd)],28 [Mo(CO)3(NCMe)3] 29 and cis-[M(C6F5)2(thf)2] 30 (M = Pt or Pd) were prepared as previously published.All other reagents were used as obtained commercially. Microanalyses were determined with Perkin-Elmer 2400 and 240-B microanalysers. Infrared spectra (KBr) were recorded on Perkin-Elmer 1600 FT and FT-IR 1000 spectrophotometers, NMR spectra on Bruker AMX-300 or ARX-300 with chemical shifts reported in ppm relative to external standards (SiMe4 for 1H and 13C, CFCl3 for 19F and H3PO4 for 31P) and mass spectra (FAB1) on a VG Autospec spectrometer. Syntheses [Ti(Á5-C5H4SiMe3)(SC]] ] CBut)2] 1a.To a diethyl ether solution (20 cm3) of LiBun (1.66 cm3, 2.66 mmol) cooled at 220 8C was added ButC]] ] CH (0.32 cm3, 2.66 mmol). After 10 min of stirring S8 (0.085 g, 0.33 mmol) was introduced in the Schlenk and the cooling bath was removed. The mixture was stirred for 45 min at room temperature and subsequently added dropwise to another diethyl ether solution (25 cm3) of [Ti(h5-C5H4SiMe3)2Cl2] (0.50 g, 1.27 mmol) cooled at 270 8C.The bright green solution obtained was kept under nitrogen with continuous stirring for 1 h while the temperature slowly reached 210 8C. The solvent was evaporated to dryness, the residue then extracted with pentane and filtered through a pad of Celite. The resulting solution was concentrated and cooled to 220 8C to yield dark green needles of complex 1a (0.63 g, 85%) (Found: C, 61.13; H, 8.03.C28H44S2Si2Ti requires C, 61.28; H, 8.08%); n& max/cm21 2129 (C]] ] C). MS: m/z 548 {(h5-C5H4SiMe3)2Ti(SC]] ] CBut)2]1, 8}, 435 {[(h5-C5H4SiMe3)2- (SC]] ] CBut)]1, 100} and 322 {[(h5-C5H4SiMe3)2Ti]1, 60%}. 1H NMR (CDCl3): d 6.46 (t, 4 H, C5H4SiMe3), 6.38 (t, 4 H, C5H4SiMe3), 1.35 (s, 18 H, But) and 0.24 (s, 18 H, SiMe3). 13C-{1H} NMR (CDCl3): d 123.3 (s, C1 of C5H4), 122.0 (s, C2,5 of C5H4), 119.4 (s, C3,4 of C5H4), 117.5 (s, C]] ] C), 80.8 (s, C]] ] C), 31.8 (s, But) and 0.17 (s, SiMe3). [Ti(Á5-C5H4SiMe3)2(SC]] ] CPh)2] 1b. This compound was obtained following the above procedure starting from [Ti(h5-C5H4SiMe3)2Cl2] (0.45 g, 0.76 mmol) and LiSC]] ] CPh (1.60 mmol).After 1.5 h of stirring the resulting diethyl ether solution was concentrated and filtered through a pad of Celite. Crystallisation from a saturated diethyl ether solution at 220 8C aVorded dark green crystals of compound 1b (85%) (Found: C, 65.03; H, 6.09. C32H36S2Si2Ti requires C, 65.28; H, 6.16%); n& max/cm21 2134 (C]] ] C). MS: m/z 588 {[(h5-C5H4SiMe3)2- Ti(SC]] ] CPh)2]1, 4}, 455 {[(Ti(SC]] ] CPh)]1, 100} and 322 {[(h5-C5H4SiMe3)2Ti]1, 95%}. 1H NMR (CDCl3): d 7.41–7.37 (m, 4 H, Ph), 7.23–7.19 (m, 6 H, Ph), 6.62 (t, 4 H, C5H4SiMe3), 6.53 (t, 4 H, C5H4SiMe3) and 0.28 (s, 18 H, SiMe3). 13C-{1H} NMR (CDCl3): d 138.8–126.9 (s, C6H5), 124.3 (s, C1 of C5H4), 122.2 (s, C2,5 of C5H4) 119.7 (s, C3,4 of C5H4), 107.3 (s, C]] ] C), 93.0 (s, C]] ] C) and 0.16 (s, SiMe3).[Ti(Á5-C5H4SiMe3)(Á5-C5H4PPh2)(SC]] ] CBut)2] 2a. This compound was obtained following the same procedure as for 1a but the final residue was extracted with heptane (73% yield). The precursors used were [Ti(h5-C5H4SiMe3)- (h5-C5H4PPh2)Cl2] (0.37 g, 0.56 mmol) and LiSC]] ] CBut (1.17 mmol) (Found: C, 66.82; H, 6.90. C37H45PS2SiTi requires C, 67.25; H, 6.86%); n& max/cm21 2145 (C]] ] C).MS: m/z 660 {[(h5-C5H4SiMe3)(h5-C5H4PPh2)Ti(SC]] ] CBut)2]1, 30}, 547 {[(h5- C5H4SiMe3)(h5-C5H4PPh2)Ti(SC]] ] CBut)]1, 100} and 432 {[(h5-C5H4SiMe3)(h5-C5H4PPh2)Ti]1, 50%}. 1H NMR (CDCl3): d 7.41–7.37 (m, 4 H, Ph), 7.23–7.19 (m, 6 H, Ph), 6.54 (m, 2 H, C5H4PPh2), 6.38 (t, 2 H, C5H4SiMe3), 6.34 (t, 2 H, C5H4SiMe3), 6.11 (m, 2 H, C5H4PPh2), 1.31 (s, 18 H, But) and 0.17 (s, 9 H, SiMe3). 31P-{1H} NMR: d 215.2 (s, C5H4- PPh2). 13C-{1H} NMR (CDCl3): d 133.8–128.5 (s, C6H5), 124.5, 123.5, 123.4, 121.8, 121.5, 120.3, 120.1, 120.0, 119.9, 119.1 (s, C5H4), 117.8 (s, C]] ] C), 80.2 (s, C]] ] C), 31.7 (s, But) and 0.11 s, SiMe3). [Ti(Á5-C5H4PPh2)2(SC]] ] CBut)2] 3a. The synthesis was performed as described for complex 1a starting from [Ti(h5-C5H4PPh2)2Cl2] (0.45 g, 0.73 mmol) and LiSC]] ] CBut (1.53 mmol).After 30 min of stirring the resulting diethyl ether solution was concentrated and filtered through a pad of Celite. The solvent was evaporated to dryness aVording 3a as a green solid (70%). n& max/cm21 2129 (C]] ] C). 1H NMR (CDCl3): d 7.27–7.17 (m, 10 H, Ph), 6.40 (t, 4 H, C5H4PPh2), 6.01 (m, 4J. Chem. Soc., Dalton Trans., 1998, 3199–3208 3205 H, C5H4PPh2) and 1.33 (s, 18 H, But). 31P-{1H} NMR: d 215.5 (s, C5H4PPh2). The 13C NMR spectrum could not be recorded due to the low stability in solution. [(Á5-C5H4SiMe3)2Ti(Ï-SC]] ] CBut)2Mo(CO)4] 4a (syn and anti). To a solution of [Ti(h5-C5H4SiMe3)2(SC]] ] CBut)2] 1a (0.20 g, 0.36 mmol) in toluene (25 cm3) was added [Mo(CO)4(nbd)] (0.32 g, 1.08 mmol) and the mixture stirred at room temperature for 30 h.The solvent was removed in vacuo and the solid obtained purified by chromatography on silica gel 100. Elution with hexane–toluene (3 : 1) aVorded a green-blue band of complex 4a (0.16 g, 60%) (syn : anti ratio ª1 : 1). Identical results were obtained starting from 1a and 1 equivalent of [Mo(CO)4(nbd)], but in that case longer periods of stirring (ª72 h) were necessary (Found: C, 50.51; H, 5.73.C32H44MoO4S2Si2Ti requires C, 50.79; H, 5.86%). n& max/cm21 2072 (C]] ] C); (toluene solution) 2019s, 1929s, 1915vs (CO). MS: m/z 756 {[(h5-C5H4SiMe3)2Ti- (m-SC]] ] CBut)2Mo(CO)4]1, <5}, 728 {[(h5-C5H4SiMe3)2Ti(m-SC]] ] CBut)2Mo(CO)3]1, <5%}, 700 {[(h5-C5H4SiMe3)2Ti(m-SC]] ] CBut)2Mo(CO)2]1, <5}, 672 {[(h5-C5H4SiMe3)2Ti(m-SC]] ] CBut)2- Mo(CO)]1, <5}, 644 {[(h5-C5H4SiMe3)2Ti(m-SC]] ] CBut)2Mo]1, 15}, 435 {[(h5-C5H4SiMe3)2Ti(SC]] ] CBut)]1, 50} and 322 {[(h5- C5H4SiMe3)2Ti]1, 100%}. 1H NMR (CDCl3): at 250 8C, d 6.30 (2 H), 6.22 (2 H, 6.12, 5.84, 5.67 (1 H each), 5.52 (2 H), 5.26 (4 H), 5.12, 4.88, 4.79 (1 H each) (C5H4 syn, anti isomers), 1.20s, 1.17s (But), 0.37 (s, SiMe3, anti isomer), 0.42s, 0.22s (SiMe3, syn isomer); at 20 8C, 6.31 (s, br, 2 H, C5H4, syn isomer), 6.21 (s, br, 2 H, C5H4, syn isomer), 5.55 (s, br, 6 H, C5H4, anti and syn isomers), 5.36 (s, br, 2 H, C5H4, syn isomer), 5.27 (s, br, 4 H, C5H4, anti isomer), 1.23 (s, But), 1.20 (s, But), 0.39 (s, 18 H, SiMe3, anti isomer), 0.44, 0.33 (s, SiMe3, syn isomer), (ratio syn : anti ª1 : 1); at 150 8C, cyclopentadienyl region very broad (ª6.2, 5.4 br), 1.24 (s, But), 0.41 (s, br, SiMe3). 13C-{1H} NMR (CDCl3): d 217.9 (s, CO equatorial, syn isomer), 217.2 (s, CO equatorial, anti isomer), 204.7 (s, CO axial, syn isomer), 203.1 (s, CO axial, anti isomer), 201.7 (s, CO axial, syn isomer), 129.3br, 123.4br, 116.8, 114.5, 113.3, 112.4, 106.2, 102.2, 101.2 (s, C5H4, C]] ] C), 75.9 (s, C]] ] C), 31.1 [s, C(CH3)3], 28.9 (s, CMe3) and 0.14 (s, SiMe3).[(Á5-C5H4SiMe3)2Ti(Ï-SC]] ] CBut)2Pt(C6F5)2] 5a (syn and anti). A deep green solution of [Ti(h5-C5H4SiMe3)2(SC]] ] CBut)2] (0.098 g, 0.178 mmol) in CH2Cl2 (10 cm3) was treated with cis-[Pt(C6F5)2(thf)2] (0.120 g, 0.178 mmol) and, immediately, turned red-brown. The mixture was stirred for 5 min and then the solvent was removed in vacuo.Addition of n-heptane (ª5 cm3) to the residue aVorded an orange-brown solid (0.153 g, 80% yield) identified as a mixture of syn and anti isomers of [(h5-C5H4SiMe3)2Ti(m-SC]] ] CBut)2Pt(C6F5)2] 5a. When the reaction was carried out in a molar ratio 1 : 2 using complex 1a (0.010 g, 0.019 mmol) and cis-[Pt(C6F5)2(thf)2] (0.025 g, 0.037 mmol) in CDCl3 (0.6 cm3) and monitored by 1H and 19F NMR spectroscopy at 20 8C the complex 5a was observed (major component) in addition to decomposition products (Found: C, 44.50; H, 3.70; S, 5.95.C40F10H44PtS2Si2Ti requires C, 44.57; H, 4.11; S, 5.48%). n& max/cm21 2168m (C]] ] C), 800vs, (br) (C6F5)X–sens. MS: m/z 1077 (M1, 28), 964 ([M 2 SC]] ] CBut]1, 32), 940 ([M 2 C5H4SiMe3]1, 25), 910 ([M 2 C6F5]1, 94), 631 {[(h5-C5H4SiMe3)2Ti(SC]] ] CBut)Pt]1, 58}, 475 {[(h5-C5H4- SiMe3)(C5H4)Ti(SC]] ] CBut)2]1, 100}, 435 {[(h5-C5H4SiMe3)2- Ti(SC]] ] CBut)]1, 70} and 322 {[(h5-C5H4SiMe3)2Ti]1, 100%}. 1H NMR (CDCl3): at 20 8C, d 6.46, 6.29, 6.23, 6.13, 5.94, 5.87, 5.73 (s, ratio 1:1:1:1:2:1:1, C5H4, syn and anti isomers), 1.21 (s, But), 1.14 (s, But), 0.39 (s, SiMe3, syn isomer), 0.33 (s, SiMe3, anti isomer), 0.25 (s, SiMe3, syn isomer), (syn : anti 0.9 : 1); approximately the same spectra is observed at 250 8C; at 150 8C, the signals are broad, 6.5, 6.3, 6.2, 5.98, 5.90, 5.80 (br, C5H4), 1.21, 1.17 (br, But), 0.35 (br, SiMe3 anti and syn isomers), 0.28 (SiMe3, syn isomer). 19F NMR [CDCl3, 3J(Pt–Fo)/Hz in parentheses]: at 250 8C, d 117.94 [dm (417)], 2118.07 [dm (ª355)], 2118.6 [dm (ª465)], 2119.4 [dm (392)] (Fo syn and anti isomers), 2161.3 (t, Fp, anti isomer), 2161.5 (t, Fp, syn isomer), 2164.2 (m, Fm, syn and anti isomers) (syn : anti 0.9 : 1); at 20 8C, 2117.6 [dm, overlapping of two Fo (ª411, ª337)], 2118.6 [dm (ª455)], 2119.3 [dm (ª385 Hz)] (ratio 2:1:1, Fo, syn and anti), 2162.0m, 2162.25m (ratio 0.9 : 1, Fp, syn and anti), 2164.5, 2165.0 (m, ratio 2 : 2, Fm, syn and anti); at 150 8C, 2117.5 [br (358)], 2118.6 [d, br (446)], 2119.2 [d, br (391)] (ratio 2:1:1, Fo, syn and anti), 2162.3 (m, br, overlapping of two Fp, syn and anti), 2164.6 (m, br), 2165.3m, (ratio 1 : 1, Fm, syn and anti). 13C-{1H} NMR (CDCl3): at 250 8C, d 148.05, 144.96, 138.5, 135.3, 123.3, 116.05 (br, C6F5), 130.1, 122.1, 120.8, 120.2, 120.0, 119.6, 113.1, 112.5, 109.6, 107.0 (s, C5H4 and C]] ] C), 67.98s, 67.78s (C]] ] C, syn and anti isomers), 30.3 [s, C(CH3)3], 29.1 (s, CMe3), 28.9 (s, CMe3), 0.0 (s, syn isomer), 20.14 (s, anti isomer) and 20.39 (s, syn isomer) [Si(CH3)3].[(Á5-C5H4SiMe3)2Ti(Ï-SC]] ] CPh)2Pt(C6F5)2] 5b (syn and anti). A solid mixture of [Ti(h5-C5H4SiMe3)2(SC]] ] CPh)2] (0.131 g, 0.223 mmol) and cis-[Pt(C6F5)2(thf)2] (0.150 g, 0.223 mmol) was treated with toluene (5 cm3).Immediately the resulting brown-red solution was concentrated in vacuo, giving an orange-red residue, identified as [(h5-C5H4SiMe3)2Ti(m- SC]] ] CPh)2Pt(C6F5)2] 5b (0.174 g, 70% yield) (syn : anti ratio at 250 8C, 1 : 1). When the reaction in a molar ratio 1 :2 {0.010 g, 0.0170 mmol of complex 1b and 0.023 g, 0.034 mmol of cis- [Pt(C6F5)2(thf)2] in 0.6 cm3 of CDCl3} was monitored by NMR spectroscopy at 20 8C considerable decomposition took place, with 5b being the major product.After longer periods (ª3 h) more decomposition was observed (Found: C, 47.47; H, 3.38; S, 5.31. C44F10H36PtS2Si2Ti requires C, 47.27; H, 3.24; S, 5.73%). n& max/cm21 2165m (C]] ] C), 801vs, (br) (C6F5)X–sens. MS: m/z 1117 (M1, 10), 619 {[(h5-C5H4SiMe3)2Ti(SC]] ] CPh)- (C6F5) 2 3H]1, 14}, 457 {[(h5-C5H4SiMe3)2Ti(SC]] ] CPh) 1 2H]1, 56} and 322 {[(h5-C5H4SiMe3)2Ti]1, 100%}. 1H NMR (CDCl3): at 250 8C, d 7.37–7.20 (Ph), 6.59, 6.46, 6.41, 6.37, 6.12, 6.09, 6.03, 5.91 (s, identical ratio, C5H4, syn and anti isomers), 0.43 (s, SiMe3, syn isomer), 0.36 (s, SiMe3, anti isomer), 0.28 (s, SiMe3, syn isomer) (syn : anti ª1 : 1); at 20 8C, 7.37–7.16 (Ph), 6.61, 6.48, 6.41, 6.17, 6.12, 6.10, 5.95 (s, ratio 1:1:2:1:1:1:1, C5H4, syn and anti isomers), 0.43 (s, SiMe3, syn isomer), 0.38 (s, SiMe3, anti isomer), 0.30 (s, SiMe3, syn isomer) (syn : anti ª1 : 1); at 150 8C, 7.36–7.15 (Ph), 6.60sh, 6.45br, 6.14br, 6.01sh (C5H4) and 0.39 (s, br, SiMe3). 19F NMR [CDCl3, 3J(Pt–Fo)/Hz in parentheses]: at 250 8C, d 2117.8 [d (430), 2F], 2118.5 [d (451), 2F], 2118.97 [d (365), 2F] 2120.0 [d (398), 2F] (Fo, syn and anti isomer), 2160.6, 2161.5 (t, Fp, syn and anti isomer), 2163.3, 2164.0 (m, Fm, syn and anti isomer) (syn : anti 1 : 1); at 20 8C, 2117.6 [d (408), 2F], 2118.6 [dm, overlapping of two Fo (ª458, ª389), 4F], 2119.8 [d (392), 2F], (Fo, syn and anti isomer), 2161.3, 2161.7 (t, Fp, syn and anti isomer), 2163.8, 2164.6 (m, Fm, syn and anti isomer) (syn : anti ª1 : 1); at 150 8C, 2117.5, 2118.3, 2118.5, 2118.98 (br, Fo), 2161.6, 2161.9 (br, Fp), 2164.0, 2164.9 (br, Fm) (syn and anti isomer). 13C-{1H} NMR (CDCl3): at 250 8C, d 148.2, 145.2, 138.7, 138.2, 135.4–134.0, 116.6, 113.8 (br, C6F5), 138.2, 131.3–112.5 (s, C6H5, C5H4), 99.3s, 96.4s (C]] ] C syn and anti isomers), 79.7s, 79.5s (C]] ] C syn and anti isomers), 20.0 (s, syn and anti isomer) and 20.35 (s, syn isomer) [Si(CH3)3]. [(Á5-C5H4SiMe3)2Ti(Ï-SC]] ] CBut)2Pd(C6F5)2] 6a (syn and anti).This product was prepared in a similar way to complex 5b by using the appropriate starting precursors, [Ti(h5-C5H4- SiMe3)2(SC]] ] CBut)2] (0.141 g, 0.256 mmol) and cis- [Pd(C6F5)2(thf)2] (0.150 g, 0.256 mmol). It was isolated by removing the solvent in vacuo, (yield 0.16 g 63%) (mixture of syn and anti isomers, ratio ª5:1 at 250 8C).When an excess of cis-[Pd(C6F5)2(thf)2] was employed {1 : 2 molar ratio; 0.012 g, 0.021 mmol of 1a and 0.025 g, 0.043 mmol of cis- [Pd(C6F5)2(thf)2] in 0.6 cm3 of CDCl3} a mixture of 6a and3206 J. Chem. Soc., Dalton Trans., 1998, 3199–3208 cis-[Pd(C6F5)2(thf)2] was observed by NMR spectroscopy (Found: C, 48.08; H, 4.21; S, 6.32.C40F10H44PdS2Si2Ti requires C, 48.56; H, 4.48; S, 6.48%). n& max/cm21 2166m (C]] ] C), 786s, 778s (C6F5)X–sens. MS: m/z 1011 ([M 1 Na]1, 2), 541 {[(h5-C5H4- SiMe3)2Ti(SC]] ] CBut)Pd]1, 7}, 492 {[(h5-C5H4SiMe3)2Pd- (SC]] ] CBut) 2 H]1, 7}, 435 {[(h5-C5H4SiMe3)2Ti(SC]] ] CBut)]1, 53} and 322 {[(h5-C5H4SiMe3)2Ti]1, 100%}. 1H NMR (CDCl3): at 250 8C, d 6.45, 6.39, 6.07, 6.00 (s, C5H4, syn isomer), 6.31, 5.72 (C5H4, anti isomer), 1.23 (s, But, syn isomer), 1.14 (s, But, anti isomer), 0.37 (s, SiMe3, syn isomer), 0.27 (s, SiMe3, anti isomer), 0.19 (s, SiMe3, syn isomer) (syn : anti 5 : 1); at 20 8C, 6.48, 6.43, 6.11, 6.07 (s, ratio 1:1:1:1, C5H4, syn isomer), 6.30, 5.81 (br, C5H4, anti isomer), 1.26 (s, But, syn isomer), 1.22 (sh, But, anti isomer), 0.37 (s, SiMe3, syn isomer), 0.30 (s, SiMe3, anti isomer) and 0.23 (s, SiMe3, syn isomer); at 150 8C, 6.42, 6.11 (br, C5H4), 1.25, (s, But) and 0.31 (s, SiMe3). 19F NMR (CDCl3): at 250 8C, d 2115.2 (d, anti isomer), 2115.5 (d, syn isomer), 2115.9 (dm, syn isomer), 2117.0 (d, anti) (Fo, ratio syn : anti 5 : 1), 2160.7 (t, overlapping of two Fp, syn and anti isomer), 2163.1, 2163.8 (br, Fm, syn and anti isomer); at 20 8C, 2114.9 (d, anti isomer), 2115.5 (m, overlapping of two Fo, syn isomer) 2116.8 (d, anti isomer) (Fo, syn : anti 3: 1), 2161.4 (t, Fp), 2163.8, 2164.5 (m, Fm, syn and anti isomer); at 150 8C, 2115.3 (br, Fo), 2161.7 (t, Fp), 2164.1, 2164.7 (br, Fm). 13C- {1H} NMR (CDCl3): at 250 8C, d 147.7, 144.7, 138.5–137.1, 135.3–133.8, 120.4 (br, C6F5), 129.4–110.0 (s, C5H4, C]] ] C), 70.0 (s, C]] ] C, anti isomer), 69.8 (s, C]] ] C, syn isomer), 30.4 [s, C(CH3)3, syn isomer], 29.3 [s, C(CH3)3, anti isomer], 29.1 (s, CMe3, syn isomer), 27.6 (s, CMe3, anti isomer), 20.17 [s, Si(CH3)3, syn isomer], 20.27 [s, Si(CH3)3, anti isomer] and 20.52 [s, Si(CH3)3, syn isomer].[(Á5-C5H4SiMe3)2Ti(Ï-SC]] ] CPh)2Pd(C6F5)2] 6b (syn and anti). The reaction was performed as described for complex 5a in toluene (5 cm3) starting from [Ti(h5-C5H4SiMe3)2(SC]] ] CPh)2] (0.150 g, 0.255 mmol) and cis-[Pd(C6F5)2(thf)2] (0.149 g, 0.255 mmol).In this case 6b was precipitated as a red-garnet solid by adding n-hexane (3 cm3) (0.23 g, 88% yield) (syn : anti at 250 8C, 10 : 1). When the reaction was carried out in a 1 : 2 molar ratio in 0.6 cm3 of CDCl3{0.013 g, 0.021 mmol of 1b and 0.025 g, 0.043 mmol of cis-[Pd(C6F5)2(thf)2]} a mixture of 6b and cis-[Pd(C6F5)2(thf)2] was observed by NMR spectroscopy (Found: C, 50.79; H, 3.61; S, 5.91.C44F10H36PdS2Si2Ti requires C, 51.34; H, 3.52; S, 6.23%). n& max/cm21 2165m (C]] ] C), 789vs, 778vs (C6F5)X–sens. MS: m/z 861 {[(h5-C5H4SiMe3)2Ti(SC]] ] CPh)2- Pd(C6F5)]1, 15}, 619 {[(h5-C5H4SiMe3)2Ti(SC]] ] CPh)- (C6F5) 2 3H]1, 14}, 457 {[(h5-C5H4SiMe3)2Ti(SC]] ] CPh) 1 2H]1, 15} and 322 {[(h5-C5H4SiMe3)2Ti]1, 100%}. 1H NMR (CDCl3): at 250 8C, d 7.29 (m), 7.17 (m) (Ph), 6.81, 6.57, 6.36, 6.28 (br, C5H4, syn isomer), 6.77, 6.45, 6.21 and 5.92 (C5H4, anti isomer), 0.38 (s, SiMe3, syn isomer), 0.31 (s, SiMe3, anti isomer), 0.22 (s, SiMe3, syn isomer) (syn : anti, 10 : 1); at 20 8C, 7.27 (m, Ph), 6.83, 6.59, 6.42, 6.31 (br, C5H4), 0.39 (s, SiMe3), 0.26 (s, SiMe3) (syn and anti isomer); at 150 8C, 7.33 (d), 7.23 (m) (Ph), 6.66 (vbr), 6.39 (vbr) (C5H4) and 0.34 (s, SiMe3). 19F NMR (CDCl3): at 250 8C, d 2115.8 (d, anti isomer), 2115.4 (d, syn isomer), 2116.7 (d, syn isomer), 2117.6 (d, anti isomer) (Fo, syn : anti 10 : 1), 2160.1 (t, Fp, anti isomer), 2160.4 (t, Fp, syn isomer), 2162.2, 2163.5 (m, Fm, syn and anti isomer); at 20 8C, 2114.8 (br, anti isomer), 2115.5 (d, syn isomer), 2116.1 (br, syn isomer), 2117.4 (br, anti isomer) (Fo, syn : anti ª7 : 1), 2161.0 (t, Fp, syn and anti isomer), 2162.9 (br), 2164.2 (m, br) (Fm, syn and anti isomer); at 150 8C, 2115.9 (br, Fo), 2161.2 (t, Fp), 2162.3 (br) and 2163.6 (br, Fm). 13C-{1H} NMR (CDCl3): at 250 8C, d 148.4, 147.6, 138.7, 138.1–137.2, 135.5, 134.9–133.8, 121.09, 118.2 (br, C6F5), 131.16, (s, Co, C6H5), 128.7, 128.4, 128.2 (s, Cm, C6H5), 125.2, 123.4, 123.1, 122.6 (s, C6H5, C5H4, syn), 103.5 (s, C]] ] C syn isomer), 81.6 (s, C]] ] C syn isomer), small signals seen at 121.1 and 99.2 (C]] ] C) tentatively attributed to the anti isomer, 20.13 [s, Si(CH3)3, anti isomer], 20.17 (s) and 20.39 (s) [Si(CH3)3, syn isomer].[(Á5-C5H4SiMe3)Ti(Ï-Á5 :Í-P-C5H4PPh2(Ï-SC]] ] CBut)2- Mo(CO)3] 7. To a toluene solution (25 cm3) of [Ti(h5-C5H4- SiMe3)(h5-C5H4PPh2)(SC]] ] CBut)2] 2a (0.20 g, 0.30 mmol) was added [Mo(CO)3(NCMe)3] (0.11 g, 0.36 mmol). After 3 h of stirring at room temperature the solvent was evaporated to dryness and the solid residue chromatographed on silica gel 100.A violet band was eluted by hexane–toluene (1 : 1) and its recrystallisation from heptane at 220 8C yielded 7 as a dark violet solid (0.13 g, 53%). Complex 7 can also be obtained in very low yield (12%) using 2a (0.23 g, 0.34 mmol) and [Mo(CO)4(nbd)] (0.12 g, 0.42 mmol) as precursors (Found: C, 56.51; H, 5.25. C40H45MoO3PS2SiTi requires C, 57.14; H, 5.39%).n& max/cm21 2070 (C]] ] C); (toluene solution) 1956vs, 1895m, 1879s (CO). MS: m/z 840 {[(h5-C5H4SiMe3)(h5-C5H4- PPh2)Ti(m-SC]] ] CBut)2Mo(CO)3]1, <5}, 784 {[(h5-C5H4SiMe3)- (h5-C5H4PPh2)Ti(m-SC]] ] CBut)2Mo(CO)]1, <5}, 756 {[(h5-C5H4- SiMe3)(h5-C5H4PPh2)Ti(m-SC]] ] CBut)2Mo]1, 100}, 547 {[(h5- C5H4SiMe3)(h5-C5H4PPh2)Ti(m-SC]] ] CBut)]1, 15} and 434 {[(h5- C5H4SiMe3)(h5-C5H4PPh2)Ti]1, 65%}. 1H NMR (CDCl3): d 7.61–7.52 (m, 4 H, Ph), 7.33–7.28 (m, 6 H, Ph), 6.23 (s, br, 2 H, C5H4PPh2), 5.61 (s, br, 2 H, C5H4SiMe3), 5.49 (s, br, 2 H, C5H4SiMe3), 5.17 (s, br, 2 H, C5H4PPh2), 1.20 (s, 18 H, But) and 0.41 (s, 9 H, SiMe3); similar spectra were obtained at low (250 8C) and high (150 8C) temperature. 31P-{1H} NMR: d 39.7 (s, C5H4PPh2). 13C-{1H} NMR (CDCl3): d 213.8 (s, CO), 133.3–128.4 (s, C6H5), 124.3–100.7 (s, C5H4), 111.4 (s, C]] ] C), 75.4 (s, C]] ] C), 31.1 [s, C(CH3)3], 28.9 [C(CH3)3] and 0.30 (s, SiMe3). [(Á5-C5H4SiMe3)(SC]] ] CBut)Ti(Ï-Á5 :Í-P-C5H4PPh2)(Ï-SC]] ] CBut)Pt(C6F5)2] 8. To a toluene solution (20 cm3) of complex 2a (0.120 g, 0.18 mmol) at 220 8C was added cis- [Pt(C6F5)2(thf)2] (0.122 g, 0.18 mmol).The cooling bath was then removed and the mixture stirred for 15 min. The resulting violet solution was subsequently filtered through a pad of Celite and concentrated (ca. 10 cm3). Addition of n-hexane (10 cm3) aVorded complex 8 as a violet crystalline solid (0.150, 70%) (Found: C, 49.85; H, 3.85. C49H45F10PPtS2SiTi requires C, 49.46; H, 3.81%). n& max/cm21 2157w, 2141m (C]] ] C), 800vs, 786vs (C6F5)X–sens.MS: m/z 1077 {[(h5-C5H4SiMe3)(h5-C5H4PPh2)- Ti(SC]] ] CBut)Pt(C6F5)2]1, 22}, 661 {[(h5-C5H4SiMe3)(h5-C5H4- PPh2)Ti(SC]] ] CBut)2]1, 55}, 548 {[(h5-C5H4SiMe3)(h5-C5H4- PPh2)Ti(SC]] ] CBut)]1, 100} and 434 {[(h5-C5H4SiMe3)(h5-C5H4- PPh2)Ti]1, 50%}. 1H NMR (CDCl3): at 250 8C, d 7.63 (m), 7.39–7.18 (m) (Ph), 7.01 (s, 2 H), 6.78, 6.68, 6.48, 6.16, 6.08, 5.90 (s, 1 H each) (C5H4), 1.20 (s, 9 H, But), 1.11 (s, 9 H, But) and 0.13 (s, 9 H, SiMe3); a similar pattern was observed at 20 8C with some of the C5H4 signals slightly displaced. 19F NMR [CDCl3, 3J(Pt–Fo)/Hz in parentheses]: at 20 8C, d 2116.6 [m (343), 1F], 2117.7 [dm (455), 1F], 2118.7 [d (414), 1F], 2120.0 [m, br (326), 1F] (Fo), 2162.7, 2163.4 (t, Fp), 2164.2 (m, 1F), 2164.5 (m, 1F), 2164.9 (m, 2F) (Fm); a similar pattern was observed at 250 8C. 31P-{1H} NMR (CDCl3): d 5.14 [s, C5H4- PPh2, 1J(Pt–P) = 2361 Hz].[(Á5-C5H4SiMe3)(SC]] ] CBut)Ti(Ï-Á5 :Í-P-C5H4PPh2(Ï-SC]] ] CBut)Pd(C6F5)2] 9. The synthesis was performed as described for complex 8 starting from 2a (0.15 g, 0.22 mmol) and cis-[Pd(C6F5)2(thf)2] (0.13 g, 0.22 mmol) (45%) (Found: C, 53.89; H, 4.19. C49H45F10PPdS2SiTi requires C, 53.44; H, 4.12%).n& max/cm21 2158w, 2141m (C]] ] C), 786vs, 776vs (C6F5)X–sens. MS: m/z 540 {[(h5-C5H4SiMe3)(h5-C5H4PPh2)Ti- (SC]] ] CBut)Pd 2 H]1, 42} and 434 {[(h5-C5H4SiMe3)(h5-C5H4- PPh2)Ti]1, 52%}. 1H NMR (CDCl3): at 250 8C, d 7.52–7.18 (m, Ph), 7.03, 7.00, 6.89, 6.71, 6.39 (s, 1 H each), 6.00 (s, 2 H), 5.86 (s, 1 H) C5H4), 1.22 (s, 9 H, But), 1.11 (s, 9 H, But) and 0.13 (s, 9 H, SiMe3); a similar pattern was observed at 20 8C. 19F NMRJ. Chem. Soc., Dalton Trans., 1998, 3199–3208 3207 Table 3 Crystal data and structure refinement for [Ti(h5-C5H4SiMe3)2(SC]] ] CBut)2] 1a and [(h5-C5H4SiMe3)(SC]] ] CBut)Ti(m-h5 :k-P-C5H4PPh2)- (m-SC]] ] CBut)Pt(C6F5)2] 8 Empirical formula Ma /Å b/Å c/Å a/8 b/8 g/8 U/Å3 Z Dc/Mg m23 F(000) m/mm21 Crystal size/mm q Range for data collection/8 hkl Index ranges Reflections collected Independent reflections Data/restraints/parameters Goodness of fit on F2 R1, wR2 Final indices [I > 2s(I)] (all data) Largest diVerence peak and hole/e Å23 1a C28H44S2Si2Ti 548.83 11.470(6) 14.170(7) 21.405(11) 94.04(3) 104.40(3) 106.26(4) 3198(3) 4 1.140 1176 0.487 0.46 × 0.13 × 0.08 2.05 to 23.53 212 to 12, 215 to 15, 0–24 9746 9454 [R(int) = 0.1162] 6527/0/547 0.967 0.0902, 0.1122 0.2820, 0.1703 0.655 and 20.665 8 C57H60F10PPtS2SiTi 1307.22 12.904(2) 14.069(1) 18.090(2) 70.18(1) 71.42(1) 74.91(1) 2885.6(6) 2 1.505 1312 2.749 0.34 × 0.30 × 0.12 2.10 to 25.00 214 to 1, 215 to 15, 220 to 20 10495 9885 [R(int) = 0.0788] 8882/0/685 1.049 0.0672, 0.1538 0.1217, 0.2064 2.599 and 1.748 Details in common: l 0.71073 Å; triclinic, space group P1� ; full-matrix least-squares refinement on F2; R1 = S(|Fo| 2 |Fc|)/S|Fo|; wR2 = [Sw(Fo 2 2 Fc 2)2/ SwFo 2]� �� ; goodness of fit = [Sw(Fo 2 2 Fc 2)2/(Nobs 2 Nparam)]; w = [s2(Fo) 1 (g1P)2 1 g2P]21; P = [max(Fo 2, 0 1 2Fc 2)]/3.(CDCl3): at 20 8C, d 2114.1 (d, 1F), 2115.05 (d, 1F), 2115.6 (d, 1F), 2117.5 (m, 1F) (Fo), 2161.95, 2161.99 (overlapping of two triplets, 2Fp), 2163.4 (m), 2163.7 (m) (3F), 2164.1 (m, 1F) (Fm); a similar pattern was observed at 250 8C. 31P-{1H} NMR (CDCl3): d 10.93 (s, C5H4PPh2). X-Ray crystallography Complex 1a. Crystals of compound 1a suitable for X-ray analysis were grown from a saturated pentane solution at 220 8C. A deep brown needle-shaped crystal was fixed with epoxy on top of a glass fiber and transferred to the cold stream of the low temperature device of a Siemens STOE/AED2 automated four circle diVractometer.Crystal data and structure refinement parameters are listed in Table 3. Data were collected at 200 K by the q–2q method. Three check reflections measured at regular intervals showed no loss of intensity at the end of data collection.An empirical absorption correction based on y scans was applied (maximum and minimum transmission factor3, 0.841). The structure was solved by the Patterson method. All non-hydrogen atoms were located in succeeding Fourier diVerence syntheses and refined with anisotropic thermal parameters. Hydrogen atoms were added at calculated positions and assigned isotropic displacement parameters equal to 1.2 or 1.5 times the Uiso value of their respective apparent carbon atoms.Two molecules of the compound were found per asymmetric unit. There was no electron density higher than 1 e Å23 in the final map. Complex 8?0.5 n-hexane?toluene. Suitable crystals of complex 8?0.5 n-hexane?toluene were obtained by slow diVusion of hexane into a toluene solution of 8 at 20 8C.A dark red crystal was mounted in inert oil on top of a glass fiber and transferred to the cold stream of the low temperature device of a Siemens P4 automated four circle diVractometer. Crystal data and structure refinement parameters are listed in Table 3. Cell constants were calculated from 50 well centered reflections with 2q angles ranging from 23 to 268.Data were collected at 173 K by the q–2q method. Three check reflections measured at regular intervals showed no significant loss of intensity at the end of data collection. The data were treated (maximum and minimum transmission factors 0.983 and 0.680) and the structure solved and refined as above. Regions of electron density located at non-bonding distances were modelled as interstitial solvent and refined with anisotropic displacement parameters.In total, there were a quarter of a molecule of n-hexane and a molecule of toluene per formula unit. Three carbon atoms, refined at half occupancy, were found for the hexane molecule, three other carbon atoms being generated by symmetry. The toluene molecule was found in two regions, with half occupancy in each and with the molecule disordered over a symmetry center.There were four peaks of electron density higher than 1 e Å23 in the final map, three located very close to the platinum atom having no chemical meaning and the other in the solvent area. 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