PMe2 Ph Research Articles

Steric control of a ruthenium-catalysed alkyne hydrogenation reaction

The cations [RuHL′ 5] + and [RuHL″ 3L′ 2] + have been used in a study of the effect of variation of group 15 donor ligands (L″, L′) on the hydrogenation reaction of alkynes. [RuHL′ 5] + was found to catalyse hydrogenation of both alkynes and alkenes, the course of the reaction being dependent on the size of the ligand L′. The rate of hydrogenation of alkynes catalysed by [RuHL′ 5] + was found to increase with the cone angle, θ, until ca 120° and then decrease as θ is raised still further. When the cone angle of L′ < 120° no alkene hydrogenation occurs. Addition of excess PMe 3 (10 equiv.) to reaction solutions containing [RuH(PMe 3) 5] + was found to increase the selectivity of the alkyne hydrogenation reaction, with concomitant decrease in the hydrogenation rate. Addition of a range of other ligands L′ (2–3 equiv.) to solutions of [RuH(COD)L″ 3] + (L″ = PMe 3, PMe 2Ph) also resulted in a decrease in the rate of the alkyne hydrogenation, but the decrease was dependent on the size of L′. The [RuHL″ 3L′ 2] + complexes were found to catalytically hydrogenate alkynes exclusively when the sum of the cone angles for the L′ and L″ ligands was 5θ = 610 ± 20°. No correlation between electronic parameters and the reaction rate and product selectivity is apparent from our results. Mechanistic features of the catalysed hydrogenation of alkenes and alkynes in the presence of these ruthenium complexes are discussed.

Further studies of the Pt II/SnCl 2 catalyzed hydroformylation

A convenient synthesis of the complexes trans-[PtCl(COEt)(PMePh 2) 2] and trans-[PtCl(COEt)(PMe 2Ph) 2] is described, and their NMR spectra in the presence of SnCl 2 are discussed. These complexes have been examined as catalysts in 1-hexene hydroformylation in the presence of an excess of SnCl 2. Their catalytic behaviour is compared with that of the systems based on complexes trans-[PtCl(COEt)(PPh 3) 2], trans-[PtHCl(PPh 3) 2], trans-[PtHCl(PEt 3) 2], and cis-[PtCl 2(PPh 3) 2].

Multi-substituted isonitrile and mixed ligand derivatives of Fe 3(CO) 12; the crystal structure of Fe 3(CO) 10(CNBu t) 2

Routes to isontrile complexes Fe 3(CO) 12− x (CNR) x (R = Bu t, Xylyl, x = 1−3) are described. The structure of Fe 3(CO) 10(CNBu t) 2 has been shown by an X-ray diffraction study to be related to that of Fe 3(CO) 12, with both isonitrile ligands attached to the unique iron atom, one in an axial and the other in an equatorial, site. The readily prepared Fe 3(CO) 9(μ 3-η 2-CNBu t) complex quantitatively takes up some Lewis bases L to give mixed-ligand derivatives Fe 3(CO) 9(CNBu t)L 2 (L = CNBu t, CNXy, P(OEt) 3, PMe 2Ph).

Disproportionation reactions of the dimeric allyliron compound [η 3-C 3H 5Fe(CO) 3] 2; formation of novel cationic η 3-allylironcarbonyl complexes

The metalmetal bonded dimer [(η 3-C 3H 5)Fe (CO) 3] 2 disproportionates on treatment with a variety of tertiary phosphines, forming the ionic allyl iron complexes [(η 3-C 3H 5)Fe(CO) 2L 2][(η 3- C 3H 5)Fe(CO) 3] (L = PMe 3, PEt 3, PMe 2Ph, PMePh 2, PPh 3). The iron(0) anionic complex has been reported previously but not the labile, iron(II) cationic complexes, which are better synthesized by treatment of (η 3-C 3H 5)Fe(CO) 3Br with the tertiary phosphines.

T-Butylimido complexes of chromium. X-ray crystal structures of Cr(NBu t) 2(PMe 2Ph)Cl 2 and [Cr(NBu t) 2(C 5H 4N) 2(η 1- O 3SCF 3)]O 3SCF 3

The compound Cr(NBu t) 2Cl 2 has been synthesized and converted to Cr(NBu t) 2(NHBu t)Cl, Cr(NBu t) 2(NHBu t) 2 and Li 2 Cr(NBu t) 4, the latter completing the series of Group 6 compounds, Li 2 M(NBu t) 4, M = Cr, Mo, W. The five-coordinate adducts, Cr(NBu t) 2Cl 2L, L = PMe 3, PMe 2Ph and Bu tNC, have been characterized as well as [Cr(NBu t) 2Cl 2] 2(μ-Ph 2PCH 2CH 2PPh 2) and the six-coordinate Cr(NBu t) 2Cl 2(2,2′-bipyridyl). Chloride substitution reactions of Cr(NBu t) 2Cl 2 lead to the compounds, Cr(NBu t) 2(η 1-O 2CMe) 2, [Cr(NBu t) 2(PMe 3) 2](O 3SCF 3) 2·0.5MeCN, [Cr(NBu t) 2py 2(η 1-O 3SCF 3)]SO 3CF 3 and [Cr(NBu t) 2(bpy) 2](PF 6) 2. The isocyanide, [Cr(NBu t) 2Cl 2(Bu tNC)], with MeLi gives the η 2-iminoacyl Cr(NBu t) 2[η 2-(Bu tNCMe)]Cl. Interaction of Cr(NBu t) 2Cl 2 with alkylating agents at low temperatures gives the chromium(V) dimer [Cl(Bu tN)Cr(μ-NBu t)] 2 in a one-electron per chromium reduction and the same product is obtained by reduction of the dihalide with (η 5-C 5H 5) 2Co. X-ray structures of compounds listed in the title have been determined.

Organoimido complexes of tungsten(IV) containing π-acceptor ligands

Reaction of PhCCPh with [WCl 2(NR)(PMe 3) 3] gives the cis-dichloro- trans- phosphine complexes [WCl 2(NR)(PhCCPh)(PMe 3) 2] [R = Ph ( 1), R = CHMe 2 ( 3)] in which the π-acceptor acetylene ligand lies cis to the imido function. For 1 v(CC) is at 1760 cm −1 and for 3, 1740 cm −1. Me 3SiCCSiMe 3 and PhCCPh do not replace phosphine ligands from [WCl 2(NPh)(PMe 3) 3] or [WCl 2(NPh)(PMePh 2) 3]. Reaction of PhCCPh with [WCl 2(NPh)(PMe 2Ph) 3] gives [WCl 2(NPh)(PhCCPh)(PMe 2Ph) 2] ( 2). Alkyl substituted acetylenes do not react cleanly with [WCl 2(NPh)(PMe 3) 3] but HCCH gives [WCl 2(NPh)(HCCH)(PMe 3) 2] ( 4). Reaction of PhCCH with [WCl 2(NR)(PMe 3) 3] gives [WCl 2(NR)(PhCCH)(PMe 3) 2] [R = Ph ( 5), R = CHMe 2 ( 6)]. The phenylacetylene ligand gives rise to asymmetry in 5 and 6 leading to AB system 31P{ 1H} NMR spectra. Different values of 1 J(PW) for the two phosphine ligands in both complexes indicate small differences in WP bonding. The acetylenic protons and carbons in the 1H and 13C{ 1H} NMR spectra of the phenylacetylene complexes couple differently to the two phosphines. For 5 3 J(HP) cis and trans = 5.90 and 17.26 Hz, 2 J(C[H]P) cis and trans = 5.29 and 21.99 Hz and 2 J(C[Ph]P) cis and trans = 4.88 and 15.63 Hz. The 13C{ 1H} NMR acetylenic carbon resonance positions in complexes 1, 3, 5 and 6 suggest that an isopropylimido ligand is a better π-donor than a phenylimido ligand, allowing more metal-acetylene π-back donation. Reduction of [WCl 3(NPh)(PMe 3) 2] with Na/Hg amalgam under CO gives [WCl 2(NPh)(CO)(PMe 3) 2] ( 7) for which v(CO) at 1925 cm −1 indicates considerable π- backbonding.

The first metal complexes containing tellurium-sulphur-nitrogen anions; X-ray structure of [Pt(TeSN 2H)(PMe 2Ph) 2][BF 4

Reaction of Te 3N 2SCl 2 with cis-PtCl 2(PMe 2Ph) 2 and 1,8-diazabicylo[5.4.0] undec-7-ene provides the first route to a metal-te

Structural and spectroscopic studies on the trinuclear clusters Re 3Cl 9(PMe 3) 3 and Re 3Cl 9(η 1-dppm) 3 (dppm  Ph 2PCH 2PPh 2)

The reactions of the trinuclear cluster Re 3Cl 9 with various phosphine ligands in ethanol have been used to prepare the new complexes Re 3Cl 9(PMe 2Ph) 3, Re 3Cl 9(η 1-dppm) 3, Re 3Cl 9(dmpm) 1.5, Re 3Cl 9(η 1-arphos) 3 and Re 3Cl 9(arphos) 1.5, where dppm = Ph 2PCH 2PPh 2, dmpm = Me 2PCH 2PMe 2 and arphos = Ph 2PCH 2CH 2AsPh 2. The 1H and 31P{ 1H} NMR spectra of several of these complexes and of Re 3Cl 9(PMe 3) 3 and Re 3Cl 9(PMePh 2) 3 are described, including studies of the dissociative ligand exchange in Re 3Cl 9(η 1-dPPM) 3. The structures of Re 3Cl 9(PMe 3) 3 and Re 3Cl 9(η 1-dppm) 3 have been established by X-ray crystallography. Crystallographic data for Re 3Cl 9(PMe 3) 3: hexagonal space group P6 3/ m, a = b = 11.614(1), c = 11.209(2) Å, α = β = 90, γ = 120°, V = 1309.4(5) Å 3 and Z = 2. The structure was refined to R = 0.038 ( R w = 0.064) for 524 data with I > 3.0σ( I). Crystallographic data for Re 3Cl 9(η 1-dppm) 3 · C 7H 8: triclinic space group P 1 , a = 11.883(3), b = 18.233(4), c = 20.102(5) Å, α = 103.32(1), β = 99.18(1), γ = 95.88(1)°, V = 4139(3) Å 3 and Z = 2. The structure was refined to R = 0.039 ( R w = 0.050) for 7190 data with I > 3.0σ( I). Both structures resemble that of the previously reported Re 3Cl 9(PEt 2Ph) 3, with Re  Re double bond distances spanning the narrow range of 2.471(1)–2.488(1) Å. The Re  P bond lengths are 2.634(4) Å for the Me 3P complex, and between 2.693(3) and 2.727(3) Å for Re 3Cl 9(η 1-dppm) 3; the presence of three monodentate dppm ligands is confirmed in the latter structure.

The preparation of mixed-ligand dithiolene complexes: X-ray structure of Pt(PMe 2Ph) 2(mnt) and [Bu 4N][Au(mnt) 2

Reaction Of PtCl 2(PR 3) 2 with sodium dithiolates gives mixed-ligand complexes such as Pt(PR 3) 2(mnt) ( 1). Attempts to prepare mixed SN/mnt complexes of gold were unsuccessful, [Bu 4N][Au(mnt) 2] ( 2) being obtained. New compounds were characterized by IR and NMR spectroscopy and microanalyses, and in the case of 1 and 2 by X-ray crystallography. Both 1 and 2 are square planar. In 2, one of the crystallographically independent anions lies over a symmetry related neighbour.

Reactions of the η 2- and η 4-isomers of Cp *Ir(2,5-dimethylthiophene) with phosphines, CO and H 2

The iridathiabenzene complex, Cp *Ir(η 2-2,5-Me 2T) ( 2), which may be formulated with a 16e − iridium centre, reacts with 2e − donor ligands (L = PMe 3, PMe 2Ph, PMePh 2, PPh 3, P(OPh) 3, and CO) to give adducts 3–8; the structures of two of these ▪ derivatives were determined by X-ray crystallography, and the bonding in their six-membered ring is contrasted with that in 2. The η 4-thiophene complex Cp *Ir(η 4-2,5-Me 2T) ( 1) also reacts with L to give the same adducts, 3–8; this reaction presumably involves 2 as an intermediate. Both 2 and 1 also undergo oxidative-addition with H 2 to give Cp *Ir(η 2-2,5-Me 2T)(H) 2 ( 9) which exists as the dihydride as determined by T 1 measurements.

Reaction of Se 4N 4 with Pt(PPh 3) 3: The preparation and X-ray structure of [Pt(Se 2N 2)(PPh 3)] 2·CH 2Cl 2

Reaction of Pt(PPh 3) 3 with Se 4N 4 in CH 2Cl 2 leads to a mixture of Pt(Se 2N 2)(PPh 3) 2 ( 1) and an intermediate species, which decomposes via loss of PPh 3 to give [Pt(Se 2N 2)(PPh 3)] 2·CH 2Cl 2 ( 2). X-ray crystallography reveals 2 to be dimeric, with [Pt(Se 2N 2)(PPh 3)] units bridged by PtN bonds in a Pt 2N 2 ring. The central [PtSe 2N 2] 2 core is planar and the geometry of the individual PtSe 2N 2 rings is comparable to that in the only other example reported, [Pt(Se 2N 2H)(PMe 2Ph) 2]Cl.

Synthesis, characterization and structure of dicarbonyl-(η 5-indenyl)(η 3-pentadienyl)molybdenum and its phosphine derivatives

The reaction between Mo(CO) 2(η 3-C 5H 7)(CH 3CN) 2Cl and LiC 9H 7 or NaC 13H 9 gives (η 5-C 9H 7)Mo(CO) 2(η 3-C 5H 7) ( 1) or (η 5-C 13H 9)Mo(CO) 2(η 3-C 5H 7) ( 2) respectively. Photolysis of 1 with excess PMe 3 and PMe 2Ph in ether at - 20°C yields (η 5-C 9H 7)Mo(CO)(PR 3)(η 3-C 5H 7) (PR 3 = PMe 3 ( 3), PMe 2Ph ( 4)). Complexes 3 and 4 exist as exo and endo isomers and have been fully characterized by elemental analyses, and from their IR, mass, and 1H NMR spectra. The crystal structure of 1 has been determined by an X-ray diffraction study; crystallographic data: space group P2 1/ C a 7.955(10), b 12.531(3), c 13.987(5) Å, β 100.86(7)°, Z = 4, R 2.4%, R w 2.3%.

Cluster Chemistry: LIX. Stereochemistry of group 15 ligand-substituted derivatives of M 3(CO) 12 (M = Ru, Os). D. Synthesis and characterisation of some tetra-substituted ruthenium complexes: X-ray structures of Ru 3(CO) 8(L) 4 (L = PMe 2Ph and P(OR) 3, R = Me, Et and Ph)

Several tetra-substituted derivatives of Ru 3(CO) 12 have been synthesised, and the molecular structures of Ru 3(CO) 8(L) 4 (L = PMe 2Ph and P(OR) 3, R = Me, Et, Ph) have been determined by single-crystal X-ray diffraction methods. The non-carbonyl ligands occupy equatorial positions in the Ru 3 triangle, one on each of two metal atoms, and two on the third. Twisting of the ML 4 moieties about the RuRu bonds is found, leading to the presence of one μ-CO ligand in the PMe 2Ph and P(OEt) 3 complexes; the latter also has two semi-bridging CO ligands about the other two RuRu bonds. The PMe 2Ph and P(OEt) 3 complexes exhibit 50 50 disorder of the Ru 3 core about a crystallographic inversion centre; the P(OMe) 3 complex has a similar 15 85 disorder in the Ru 3 core, and also in two of the OMe groups on one P(OMe) 3 ligand. A discussion of the major structural features of M 3(CO) 12− n (L) n ( n = 1–4) is given. Crystal data: Ru 3(CO) 8(PMe 2Ph) 4, triclinic, P 1 , a 12.040(2), b 10.482(6), c 9.549(4) Å, α 86.26(4), β 69.69(3), γ 78.72(3)°, U 1108.4(6) Å 3, Z = 1, N 0 (number of observed data with I > 3σ( I)) = 2056, R = 0.076, R′ = 0.075; Ru 3(CO) 8{P(OMe) 3} 4, monoclinic, P2 1, a 9.821(2), b 17.384(6), c 10.912(3) Å, β 94.88(2)°, U 1856(1) Å 3, Z = 2, N o = 2726, R = 0.041, R′ = 0.046: Ru 3(CO) 8{P(OEt) 2} 4, monoclinic, C2/ c, a 18.987(6), b 12.465(4), c 22.244(7) Å, β 102.03(3)°, U 5149(3) Å 3, Z = 4, N 0 ( I > 2σ( I) = 1729, R = 0.066, R′ = 0.048; Ru 3(CO) 8{P(OPh) 3} 4, monoclinic, P2 1/ c, a 21.14(1), b 13.820(9), c 27.24(3) Å, β 106.34(6)°, U 7637(7) Å 3, Z = 4, N 0 ( I > 2σ( I)) = 6107, R = 0.073, R′ = 0.052.

Nonplanar Rh(I) in Rh(PMe 2Ph) 4+: Magnitude and origin of the distortion

The crystal and molecular structure of Rh(PMe 2Ph) 4BF 4·0.5(tetrahydrofuran) has been determined at −144 °C. Space group P 1 with a = 11.416(2), b = 14.501(2), c = 11.195(2) Å, α = 96.53(1)°, β = 102.78(1)°, γ = 85.70(1)° and Z = 2. R( F) = 0.0497, R w( F) = 0.0519. The BF 4 − and THF do not interact with the Rh(PMe 2Ph) 4 + cation, which shows marked distortion from square planar towards tetrahedral geometry: transoid P-Rh-P angles are 150.77(8) and 150.01(8)°. Analysis of space-filling representations, and comparison to other related structures permits the conclusion that such distortions originate in the need to interleave the 12 R groups in Rh(PR 3) 4 + species.

Studies on the reactivity of the halo-hydride complexes [M(η 5-C 5H 5) 2HX] (M = Mo, W; X = Cl, Br, I)

A convenient preparation of the cations [Mo(η 5-C 5H 5) 2HL] + and [Mo(η 5-C 5H 5) 2H(LL)] + from [Mo(η 5-C 5H 5) 2HI] ( 1), L and TlPF 6(BF 4) is described for L = CO, C 2H 4, PMe 2Ph, PEt 2,Ph, PPh 3, NH 3, NCMe and LL = Ph 2PCH 2PPh 2, (dppm), H 2NCH 2CH 2NH 2 (en). Complex 1 and butadiene give [Mo(η 5-C 5H 5) 2(η 3-CH 3C 3H 4)]BF 4. The chloro and bromo analogues of 1 are less reactive, and the W analogue of 1 does not react under the conditions used for 1. Reaction of 1 with Ph 2PCH 2CH 2PPh 2 (dppe) gives the cation [Mo(η 5-C 5H 5)(η 4-C 5H 6)dppe] + ( 18) in the presence or absence of TlPF 6. The deuterido analogue of 1, 1d gives 18d having the deuterium on the exo face of the C 5H 5D ring.

Haloalkyl complexes of the transition metals: VI. A study of the reactions of halomethyldicarbonylcyclopentadienyliron complexes with some tertiary phosphine, amine and sulphur ligands

The reactions of [CpFe(CO) 2CH 2X] with a series of tertiary phosphines, amines, and SMe 2 have been investigated in both CH 3CN and THF (Cp = η 5-C 5H 5 and X = Cl, Br or I). Two types of cationic products, namely the ylide complexes [CpFe(CO) 2CH 2L] + or the disubstituted complexes [CpFe(CO)L 2] +, were obtained, depending on the halide (X), the ligand (L) and the solvent used. The reactions of [CpFe(CO) 2CH 2L]Br with L in CH 3CN gave [CpFe(CO)L 2]Br for L = PMe 3 and PMe 2Ph, suggesting that [CpFe(CO) 2CH 2L] + is an intermediate in the formation of [CpFe(CO)L 2] + from [CpFe(CO) 2CH 2X] on reaction with L. The relative rates of reaction of [CpFe(CO) 2CH 2Br] with L were determined by 1H NMR spectroscopy, and the rate found to increase with increasing p K a and decreasing cone angle of L. PBu t 3 was found not to react with [CpFe(CO) 2CH 2Cl] under any of the conditions used, although it readily reacts with [CpFe(CO) 2CH 2Br] to form the cationic ylide complex. In general, the rate of reaction of [CpFe(CO) 2CH 2X] with L increases in the sequence Cl < Br < I. The reaction of [CpFe(CO) 2CH 2Br] with bis(diphenylphosphino)ethane yields a bridged dicationic ylide complex [Cp(CO) 2FeCH 2P(Ph) 2(CH 2) 2P(Ph) 2CH 2Fe(CO) 2Cp] 2+.

Reactivity of MOCl(L) (M = Tc or Re; L = N-(2-oxidophenyl)salicylideneiminate or N-(2-sulphidophenyl)salicylideneiminate) with tertiary phosphines. X-ray molecular structure of μ-oxo-bis[( N-(2-oxidophenyl)salicylideneiminato(2-) NOO′)bis(dimethylphenylphosphine)technetium(III)

μ-O[Tc(L)(P) 2] 2 and ReOCl(L)(P) complexes (L = N-(2-oxidophenyl)salicylideneiminate (L 1) or N-(2-sulphidophenyl)salicylideneiminate (L 2) and P = PMe 2Ph or PPh 3) were synthesized starting from the MOCl(L) (M = Tc or Re) compounds. The characterization was performed by means of the usual physicochemical techniques and for μ-O[Tc(L 1)(PMe 2Ph) 2] 2 by means of X-ray structure determination. In the complex the coordination around each technetium atom is approximately octahedral with two phosphine ligands in the trans position and the remaining four equatorial sites occupied by ONO donor atom set of L 1 ligand and the bridge-oxo oxygen. Consequently the oxo oxygen is trans to the imino nitrogen of the L 1 ligand. The complex crystallizes in triclinic space group P 1 with a = 16.709(7), b = 15.255(6), c = 11.702(4) Å, α = 104.43(5), β = 86.49(6), γ = 106.91(6)° , U = 2763.6(1.8) Å 3, Z = 2. The structure has been refined to R = 0.08 for 2311 independent reflections.

Reactions of the hetero-metallic complexes [WReCO 2(μ 3-CC 6H 4Me-4)(CO) 15] and [ReCo 2(μ 3-CC 6H 4Me-4)(CO) 10] with secondary and tertiary phosphines

Reaction of the complex [WReCO 2(μ 3-CC 6H 4Me-4)(CO) 15] with PMe 2Ph gives a mixture of the mono- and bis-phosphine complexes [WReCo 2(μ 3-CC 6H 4Me4)(CO) 15− x (PMe 2Ph) x ] ( x = 1 or 2), whilst that with the bidentate phosphine Ph 2PCH 2PPh 2 (dppm) affords [WReCo 2(μ 3-CC 6H 4Me-4)(CO) 13(Ph 2PCH 2PPh 2)]. In contrast, reaction with two equivalents of the secondary phosphine PPh 2H gives the phosphido-bridged derivative [WCo 2(μ 3-CC 6H 4)(μ-PPh 2)(CO) 8(PPh 2H)]. Formation of the latter WCo 2 complex involves formal loss of [ReH(CO) 5] and a mechanism for this process is discussed. Treatment of the related ReCO 2 compound [ReCo 2(μ 3-CC 6H 4Me-4)(CO) 10] with dppm affords the mono- and bis-dppm derivatives [ReCo 2(μ 3-CC 6H 4Me-4)(CO) 8(Ph 2PCH 2PPh 2)] and [ReCo 2(μ 3-CC 6H 4Me-4)(CO) x (Ph 2PCH 2PPh 2) 2] ( x = 6 or 7) respectively. As previously reported, treatment of [ReCr(CC 6H 4Me-4)(CO) 9] with [Co 2(CO) 8] gives [CrReCo 2(μ 3-CC 6H 4Me-4)(CO) 15], which thermally rearranges to [ReCo 2(μ 3-CC 6H 4Me-4)(CO) 10]. The new complexes [Re 2Co 2{μ-(RCCR)}(CO) 12] and [CrReCo 2(μ 3-CC 6H 4Me-4)(CO) 13] have been identified as by-products in the latter reactions. Spectroscopic data for the new compounds are reported and discussed in the context of the structures proposed.

The preparation and X-ray structures of Pt(SeSN 2)(PMe 2Ph) 2 and [Pt(SeSN 2H)(PMe 2Ph) 2]BF 4

Reaction of [Se 2SN 2] 2Cl 2 with PtCl 2(PMe 2Ph) 2 in liquid ammonia gives Pt(SeSN 2)(PMe 2Ph) 2 ( 4), which may be protonated with HBF 4 to form [Pt(SeSN 2H) (PMe 2Ph) 2]BF 4 ( 5); the new compounds being characterized by IR, NMR and X-ray crystallography.

Cluster condensations. The decarbonylation and dimerization of the sulphur-bridged cluster complexes Ru 3(CO) 8L(μ 3-HC 2Ph)(μ 3-S) (L = CO and PMe 2Ph). X-ray crystal structures of Ru 3(CO) 8(PMe 2Ph)(μ 3-HC 2Ph)(μ 3-S), [Ru 3(CO) 8(μ 3-HC 2Ph)(μ 4-S)] 2 and two isomers of [Ru 3(CO) 7(PMe 2Ph)(μ 3-HC 2Ph)(μ 4-S)] 2

The compounds Ru 3(CO) 9(μ 3-HC 2Ph)(μ 3-S) ( 1) and Ru 3(CO) 8(PMe 2Ph)(μ 3- HC 2Ph)(μ 3-S) ( 2) are decarbonylated when heated to 68°C and condense to form the dimers [Ru 3(CO) 8(μ 3-HC 2Ph)(μ 4-S)] 2 ( 3) and two isomers of [Ru 3(CO) 7(PMe 2Ph)(μ 3-HC 2Ph)(μ 4-S)] 2 ( 4) and ( 5), respectively. Compounds 2, 3, 4 and 5 were characterized by single-crystal X-ray diffraction. Compounds 1 and 2 are open clusters that have a triply bridging sulphido ligand and a triply bridging HC 2Ph ligand. Compounds 3, 4 and 5 are dimers of the decarbonylated forms of 1 and 2 that are joined by two S → Ru donor-acceptor bonds, one from each cluster to the other. Compounds 3 and 4 are centrosymmetric and were formed by the combination of enantiomers of the cluster precursors. Compound 5 is chiral but has overall C 2 symmetry and was formed by the combination of enantiomerically similar monomeric units. Compound 5 is converted to 4 when heated, but the reverse does not occur.