A study of the photochemistry and thermal chemistry of Ru3(CO)9(PR3)3{R = Ph,OMe} with two-electron donor ligands

The photochemistry of the tris-substituted clusters Ru₃(CO)₉(PR₃)₃ (R=Ph or OMe) with no added ligands, with CO, C₂H₄, alkynes and H₂ is compared and contrasted with results obtained for analogous thermal reactions. Photolysis of a CH₂Cl₂ solution of Ru₃(CO)₉(PPh₃)₃ leads to the metallated complex HRu₃(CO)₈(PPh₃)₂(PPh₂C₆H₄). In CCl₄, Ru(CO)₃(PR₃)Cl₂ is formed on photolysis of Ru₃(CO)₉(PR₃)₃. Photolysis of CO saturated solutions of Ru₃(CO)₉(PR₃)₃ leads to Ru(CO)₄(PR₃). C₂H₄ saturated solutions of Ru₃(CO)₉(PR₃)₃ generate the novel Ru(CO)₃(PR₃)(²-C₂H₄) complexes upon photolysis. With C₂H₂, photolysis of solutions of Ru₃(CO)₉(PR₃)₃ leads to the novel complexes Ru(CO)₃(PR₃)(²-C₂H₂). Substituted alkyne complexes have been prepared. Thermolysis of Ru₃(CO)₉(PR₃)₃ with HCCPh leads to the novel acetylide clusters HRu₃(CO)₆(PR₃)₃(₃-²-C₂Ph). With PhC CPh, only Ru₃(CO)₉{P(OMe)₃}₃ reacts, yielding the novel alkyne cluster Ru₃(CO)₆{P(OMe)₃}₃(₃-²-C₂Ph₂). With H₂, photolysis of CH₂Cl₂ solutions of Ru₃(CO)₉(PR₃)₃ leads to H₂Ru(CO)₂(PR₃)₂. Irradiating a 4:1 CH₂Cl₂ to EtOAc solution of Ru₃(CO)₉(PR₃)₃ under an atmosphere of H₂ leads to the novel dihydrido species H₂Ru₃(CO)₇(PR₃)₃. Thermolysis of H₂ saturated solutions of Ru₃(CO)₉(PR₃)₃ leads to H₄Ru₄(CO)₈(PR₃)₄.     

Derivate des borols: IX. (η5-borol)metall-komplexe von ruthenium,osmium und rhodium

Dehydrogenating complexation of borolenes with carbonyls (Ru₃(CO)₁₂, Os₃(CO)₁₂), Wilkinson's catalyst (RhCl(PPh₃)₃) and related compounds (RuCl₂(PPh₃)₃, RuHCl(PPh₃)₃, OSCl₂(PPh₃)₃), and (η⁶-arene)ruthenium complexes (Ru(η-C₆H₆)(η⁴-C₆H₈), [Ru(η-C₆H₆)Cl₂]₂, [Ru(η-C₆-Me₆)Cl₂]₂) leads to the (η⁵-borole)metal complexes of Ru, Os, and Rh. Inter alia, the preparation of the complexes Ru(CO)₃(η⁵-C₄H₄BF) (R = Ph, OMe, Me), Os(CO)₃L (L = η⁵-C₄H₄BPh), MHClL(PPh₃)₂ (M = Ru, Os), RhClL(PPh₃)₂, and RuL(η-C₆R₆) (R = H, Me) is described. The structures of RuHClL(PPh₃)₂ and RhClL(PPh₃)₂ have been determined by X-ray diffraction analysis.     

Photochemically promoted regiospecific P–C bond cleavage in the diruthenium compound Ru2(CO)2(bmf): X-ray diffraction structure of Ru2(CO)6[μ-C=C(PPh2)C(O)OCH(OMe)](μ-PPh2)

The ruthenium cluster Ru₃(CO)₁₂ reacts with the diphosphine ligand 3,4-bis(diphenylphosphino)-5-methoxy-2(5H)-furanone (bmf) in refluxing toluene to furnish the donor–acceptor compound Ru₂(CO)₂(bmf) as a 1?:?1 mixture of diastereomers. Photolysis of Ru₂(CO)₂(bmf) using 366?nm light leads to the oxidative cleavage of a P–C bond and formation of the phosphido-bridged complex Ru₂(CO)₆[μ-C=C(PPh₂)C(O)OCH(OMe)](μ-PPh₂). The regioselective Ph₂P–C(furanone ring) bond activation attendant upon optical excitation is traced to the phosphine group that was β to the furanone carbonyl group, as established by X-ray analysis of one of the diastereomers of Ru₂(CO)₆[μ-C=C(PPh₂)C(O)OCH(OMe)](μ-PPh₂). Both diruthenium products have been fully characterized in solution by IR and NMR (¹H and ³¹P) spectroscopies and elemental analyses. The observed regioselectivity associated with the P–C bond activation in Ru₂(CO)₂(bmf) is discussed with respect to the chemistry of other bmf-substituted compounds prepared by our groups.     

Synthesis,Characterization, and X‐ray Structures of Ru3(CO)9(dotpm)(L) Complexes [L = PPh3, P(C6H4Cl‐p)3, and PPh2(C6H4Br‐p)]

The reaction of Ru₃(CO)₁₀(dotpm) ( 1 ) [dotpm = (bis(di‐ortho‐tolylphosphanyl)methane)] and one equivalent of L [L = PPh₃, P(C₆H₄Cl‐p)₃ and PPh₂(C₆H₄Br‐p)] in refluxing n‐hexane afforded a series of derivatives [Ru₃(CO)₉(dotpm)L] ( 2 – 4 ), respectively, in ca. 67–70 % yield. Complexes 2 – 4 were characterized by elemental analysis (CHN), IR, ¹H NMR, ¹³C{¹H} NMR and ³¹P{¹H} NMR spectroscopy. The molecular structures of 2 , 3 , and 4 were established by single‐crystal X‐ray diffraction. The bidentate dotpm and monodentate phosphine ligands occupy equatorial positions with respect to the Ru triangle. The effect of substitution resulted in significant differences in the Ru–Ru and Ru–P bond lengths.     

A convenient entry into diruthenium chemistry

In boiling toluene, diphenylacetylene is readily displaced from the dimetallocycle [Ru₂(CO)(μ-CO) {μ-C(O)C₂Ph₂} (η-C₅H₅)₂] by a variety of reagents (P(OMe)₃, SO₂, R₂CN₂, Ph₂PCH₂) to produce [Ru₂(CO){P(OMe)₃}(μ-CO)₂ - (η-C₅H₅)₂] or [Ru₂(CO)₂(μ-CO)(μ-L)(η-C₅H₅)₂] (L  SO₂, CR₂, CH₂) in high yield.     

The μ3-cyclopentadienylidene ligand: X-ray structure of [Ru4(CO)5 {P(OMe)3}(μ3-C5H4)2(η-C5H5)2]

UV irradiation of [Ru₂(CO)₄(η-C₅H₅)₂] yields the tri- and tetra-ruthenium complexes [Ru₂(CO)₄(η-C₅H₅){η-C₅H₄Ru(CO)₂(η-C₅H₅)}] and [Ru₄(CO)₆(μ₃-C₅H₄)₂(η-C₅H₅)₂]. The μ₃-C₅H₄ ligand in the latter has been characterised through an X-ray diffraction study on [Ru₄(CO)₅{P(OMe)₃}(μ₃-C₅H₄)₂(η-C₅H₅)₂].     

Addition and migration of ligands on a metal atom pair: The oxidative addition of hexafluoro-2-butyne to dinuclear dihydridoiridium(II) complexes [Ir(H)(μ-SBu-t)(CO)(PR3)]2(IrIr) (R = OMe or Me), and its dehydrogenation reaction when R = OMe

Dissymmetric dinuclear complexes (PR₃)(CO)(H)₂Ir(μ-SBu-t)₂Ir(C₄F₆(CO)-(PR₃) (III, R = OMe or Me), which can be described as the juxtaposition of dihydrido and alkyne adducts of Vaska's complex associated through thiolato bridges, were obtained by the reaction of hexafluoro-2-butyne with symmetric dinuclear dihydridoiridium(II) complexes, [Ir(H)(μ-SBu-t)(CO)(PR₃)]₂(]IrIr) (II). When R = OMe, after the loss of H₂, a molecular rearrangement leads to the symmetric dinuclear iridium(II) complex [Ir(μ-SBu-t)(CO)(P(OMe)₃)]₂(C₄F₆) (IV). A correlation between the presence of an intense absorption near 230 nm in the UV-visible spectra and the existence of a metal—metal bond is established. A sequence of formation, splitting and re-formation of the metal—metal bond is observed along the series of derivatives obtained from [Ir(μ-SBu-t)(CO)P(OMe)₃]₂ (I) to IV, via II and III.     

Substituted cyclopentadienyl ligands—10. Intramolecular steric interactions in [(η-C5H3(SiMe3)2)Mo(CO)2(L)I]

Reaction of C₅H₄(SiMe₃)₂ with Mo(CO)₆ yielded [(η⁵-C₅H₃(SiMe₃)₂)Mo(CO)₃]₂, which on addition of iodine gave [(η⁵-C₅H₃(SiMe₃)₂Mo(CO)₃I]. Carbonyl displacement by a range of ligands: [L  P(OMe)₃, P(OPrⁱ)₃,P(O-o-tol)₃, PMe₃, PMe₂Ph, PMePh₂, PPh₃, P(m-tol)₃] gave the new complexes [(η⁵-C₅H₃(SiMe₃)₂ MO(CO)₂(L)I]. For all the trans isomer was the dominant, if not exclusive, isomer formed in the reaction. An NOE spectral analysis of [(η⁵-C₅H₃(SiMe₃)₂)Mo(CO)₂(L)I] L  PMe₂Ph, P(OMe)₃] revealed that the L group resided on the sterically uncongested side of the cyclopentadienyl ligand and that the ligand did not access the congested side of the molecule. Quantification of this phenomenon [L  P(OMe)₃] was achieved by means of the vertex angle of overlap methodology. This methodology revealed a steric preference with the trans isomer (less congestion of CO than I with an SiMe₃ group) being the more stable isomer for L  P(OMe)₃.     

Supported metals and metal oxides as promoters for the metal dimer and cluster catalysed co substitution reaction

Promotional effects due to PtO₂, PdO, Pd/C and Pd/CaCO₃ on the metal dimer or cluster (e.g. [(η⁵-C₅H₅)Fe(CO)₂]₂, Ru₃(CO)₁₂, Ir₄(CO)₁₂) catalysed reaction between metal carbonyls and isonitriles are shown to lead to enhanced reaction rates for the metal carbonyl substitution reaction.     

Synthesis and structural characterization of the hydrido carbido ruthenium cluster [PPh4][Ru6C(CO)16H]

According to the protonation of [PPh₄]₂[Ru₆C(CO)₁₆] (1b) withp-toluene-sulfonic acid, a hydrido ruthenium cluster [PPh₄][Ru₆C(CO)₁₆H] (3b) was obtained in 53% yield, which readily decomposed in protic solvents even at –20°C to yield1b, Ru₆C(CO)₁₆H₂, and Ru₅C(CO)₁₅. Cluster3b was characterized by single-crystal X-ray analysis. The six metal atoms are arranged in the form of an octahedron with the carbido ligand located in the center. There are 13 terminal carbonyl, three bridging carbonyl, and a bridging hydrido ligands.     

Phosphine-substituted diiron 1,2-dithiolate complexes as the models for the active site of [FeFe]-hydrogenases

Abstract

In this article, five diiron 1,2-dithiolate complexes containing phosphine ligands are reported. Treatment of complex [Fe₂(CO)₆(μ-SCH₂CH₂S)] (1) with the phosphine ligands tris(4-methylphenyl)phosphine, tris(4-methoxyphenyl)phosphine, tris(3-chlorophenyl)phosphine, tris(3-methylphenyl)phosphine, or 2-(diphenylphosphino)biphenyl in the presence of Me₃NO·2H₂O as the decarbonylating agent afforded the target products [Fe₂(CO)₅(L)(μ-SCH₂CH₂S)] [L?=?P(4-C₆H₄CH₃)₃, 2; P(4-C₆H₄OCH₃)₃, 3; P(3-C₆H₄Cl)₃, 4; P(3-C₆H₄CH₃)₃, 5; Ph₂P(2-C₆H₄Ph), 6] in 80–93% yields. Complexes 2–6 have been characterized by elemental analysis, spectroscopy, and X-ray crystallography. Additionally, the electrochemical properties were studied by cyclic voltammetry.     

Synthesis and properties of Zr-Co heterodinuclear complexes with a bridging bis(cyclopentadienyl) ligand

[(η⁵-C₅H₅)ZrCl₂(η⁵-C₅H₄)CMe₂(C₅H₅)] reacted with Co₂(CO)₈ to produce a heterodinuclear Zr(IV)-Co(I) complex [(η⁵-C₅H₅)ZrCl₂(η⁵-C₅H₄)CMe₂(η⁵-C₅H₄)Co(CO)₂] (3). Complex 3 underwent oxidative addition of I₂ to give [(η⁵-C₅H₅)ZrCl₂(η⁵-C₅H₄)CMe₂(η⁵-C₅H₄)CoI₂(CO)] (4) having Zr(IV) and Co(III) centers. The carbonyl ligand of 4 was easily replaced with P(OMe)₃ and PPh₃ to afford [(η⁵-C₅H₅)ZrCl₂(η⁵-C₅H₄)CMe₂(η⁵-C₅H₄)CoI₂(L)] (5: L = P(OMe)₃, 6: L = PPh₃). Structures of 5 and 6 were determined by X-ray crystallography. These Zr-Co heterodinuclear complexes catalyzed polymerization of ethylene and propylene.     

Mixed-metal cluster synthesis: [Re(CO)3(μ-S2NC7H4)]2 as a precursor for tri- and tetranuclear 2-mercaptobenzothiolato capped clusters

The readily prepared [Re₂(CO)₆(μ-S₂NC₇H₄)₂] (1) reacts with Group 8 trimetallic carbonyl clusters to yield new mixed-metal tri- and tetranuclear clusters. With [Os₃(CO)₁₀(NCMe)₂] at 80 °C the tetranuclear mixed-metal cluster [Os₃Re(CO)₁₃(μ₃-C₇H₄NS₂)] (2) is the only isolated product. With Ru₃(CO)₁₂ products are dependent upon the reaction temperature. At 80 °C, a mixture of tetranuclear mixed-metal [Ru₃Re(CO)₁₃(μ₃-C₇H₄NS₂)] (5) and the triruthenium complex [Ru₃(CO)₉(μ-H)(μ₃-C₇H₄NS₂)] (4) results, while at 110 °C a second tetranuclear mixed-metal cluster, [Re₂Ru₂(CO)₁₂(μ₄-S)(μ-C₇H₄NS)(μ-C₇H₄NS₂)] (3), resulting from carbon-sulfur bond scission, is the major product. Reaction of 1 With Fe₃(CO)₁₂ at 80 °C furnishes the trinuclear mixed-metal cluster [Fe₂Re(CO)₈(μ-CO)₂(μ₃-C₇H₄NS₂)] (6). The reactivity of 6 has been probed with the aim of identifying any metal-based selectivity for carbonyl substitution. Addition of PPh₃ in presence of Me₃NO at 25 °C gives both the mono- and bis(phosphine)-substituted derivatives [Os₃Re(CO)₁₂(PPh₃)(μ₃-C₇H₄NS₂)] (7) and [Os₃Re(CO)₁₁(PPh₃)₂(μ₃-C₇H₄NS₂)] (8). In 7 the PPh₃ ligand occupies an axial site on wingtip osmium, while in 8 one PPh₃ ligand is equatorially coordinated to wingtip osmium and the other is bonded to a hinge osmium. New complexes have been characterized by a combination of spectroscopic data and single crystal X-ray diffraction studies.     

Carbonyl substitution chemistry of some trimetallic transition metal cluster complexes with polyfunctional ligands

The trimetallic clusters [Ru₃(CO)₁₀(dppm)], [Ru₃(CO)₁₂] and [RuCo₂(CO)₁₁] react with a number of multifunctional secondary phosphine and tertiary arsine ligands to give products consequent on carbonyl substitution and, in the case of the secondary phosphines, PH activation. The reaction with the unresolved mixed P/S donor, 1-phenylphosphino-2-thio(ethane), HSCH₂CH₂PHPh ( LH₂), gave two products under various conditions which have been characterised by spectroscopic and crystallographic means. These two complexes [Ru₃(μ-dppm)(H)(CO)₇(LH)] and [Ru₃(μ-dppm)(H)(CO)₈(LH)Ru₃(μ-dppm)(CO)₉], show the versatility of the ligand, with it chelating in the former and bridging two Ru₃ units in the latter. The stereogenic centres in the molecules gave rise to complicated spectroscopic data which are consistent with the presence of diastereoisomers. In the case of [Ru₃(CO)₁₂] the reaction with LH₂ gave a poor yield of a tetranuclear butterfly cluster, [Ru₄(CO)₁₀(L)₂], in which two of the ligands bridge opposite hinge wingtip bonds of the cluster. A related ligand, HSCH₂CH₂AsMe(C₆H₄CH₂OMe), reacted with [RuCo₂(CO)₁₁] to give a low yield of the heterobimetallic Ru-Co adduct, [RuCo(CO)₆(SCH₂CH₂AsMe(C₆H₄CH₂OMe))], which appears to be the only one of its type so far structurally characterised.The secondary phosphine, HPMe(C₆H₄(CH₂OMe)) and its oxide HP(O)Me(C₆H₄(CH₂OMe)) also react with the cluster [Ru₃(CO)₁₀(dppm)] to give carbonyl substitution products, [Ru₃(CO)₅(dppm)(μ₂-PMe(C₆H₄CH₂OMe))₄], and [Ru₃H(CO)₇(dppm)(μ₂,η¹-P(O)Me(C₆H₄CH₂OMe))]. The former consists of an open Ru₃ triangle with four phosphide ligands bridging the metal-metal bonds; the latter has the O atom symmetrically bridging one Ru-Ru bond, the P atom being attached to a non-bridged Ru atom.     

Steric and Electronic Influences in Os3(CO)11(PR3) Structures

The structures of Os₃(CO)₁₁(PR₃) with R=F, OPh, Et, p-C₆H₄Me, o-C₆H₄Me, p-C₆H₄(CF₃) and C₆H₁₁, and with PR₃=P(OCH₂)₃CMe have been determined. The Os–Os bond lengths in these compounds are compared to the Os–Os lengths for the other structures of Os₃(CO)₁₁(PR₃) clusters reported in the literature. In most cases, the Os–Os bond length remote from the P ligand [range, 2.8666(4)–2.9044(4) Å] and that in the pseudo-trans position [range, 2.8712(5)–2.900(1) Å] show little variation as the steric and electronic properties of the P ligand are varied. The Os–Os length cis to PR₃ shows more variation [range, 2.879(1)–2.9429(4) Å] and is sensitive to both the size and the -donor/-acceptor properties of the PR₃ ligand: larger or better donor PR₃ ligands cause an increase in the Os–Os bond length. The Os–P distances [range, 2.15(2)–2.478(1) Å] show a similar dependence on the steric and electronic properties of the PR₃ ligand.     

Cluster-containing carbon-rich molecules: Reactions of ruthenium cluster carbonyls with {Au(PR3)}2(μ-CCCC) (R = Ph, tol)

Complexes containing C₄ ligands attached to one or two AuRu₃ clusters by conventional σ, 2π interactions have been obtained from reactions between (R₃P)AuC≡CC≡CAu(PR₃) (R = Ph, tol) or Au(C≡CC≡CH){P(tol)₃} and either Ru₃(CO)₁₂, Ru₃(CO)₁₀(NCMe)₂ or Ru₃(μ-dppm)(CO)₁₀. The X-ray determined structures of {(R₃P)AuRu₃(CO)₉}₂(μ₃,η²:μ₃,η²-C₂C₂) [R = Ph (1) (three solvates), tol (2)], AuRu₃{μ₃,η²-C₂C≡CAu(PPh₃)}(CO)₉(PPh₃) (3) and {(Ph₃P)AuRu₃(μ-dppm)(CO)₇} (μ₃,η²:μ₃,η²-C₂C₂){Ru₃(μ-H)(μ-dppm)(CO)₇} (4) are reported.     

Metal Cluster Terminated “Molecular Wires”

The gold complexes Au(C≡CC₆H₄C≡CC₆H₄Me)(PPh₃) (3) and {Au(PPh₃)}₂(μ-C≡CC₆H₄C≡CC₆H₄C≡CC₆H₄C≡C) (6), prepared from the reaction of AuCl(PPh₃) with the corresponding terminal or trimethylsilyl protected alkynes, react readily with Ru₃(CO)₁₀(μ-dppm) to afford phenylene ethynylene derivatives featuring the Ru₃(μ-AuPPh₃)(μ-C₂R)(CO)₇ cluster “end-caps”. The hydrido cluster Ru₃(μ-H)(μ-C₂C₆H₄C≡CC₆H₄Me)(CO)₇ (4a) has also been obtained. There are significant differences in the absorption spectra of the organic precursors, the gold complexes and the clusters indicate a mixing of electronic states between the cluster and phenylene ethynylene moieties, while the presence of the Ru₃ and in particular Ru₃(μ-AuPPh₃) cluster end-caps leads to a quenching of the phenylene ethynylene centred emission. The crystallographically determined structures of 3, 4a and Ru₃(μ-AuPPh₃) (μ-C₂C₆H₄C≡CC₆H₄Me)(CO)₇ (4b) are reported.Dedicated to Professor B.F.G. Johnson, one of the pioneers of cluster chemistry, in recognition of his outstanding contributions to the field.     

Reaction of [Ru3(CO)12] with tri(2-furyl)phosphine: Di- and tri-substituted triruthenium and phosphido-bridged diruthenium complexes

Reaction of [Ru₃(CO)₁₂] with tri(2-furyl)phosphine, P(C₄H₃O)₃, at 40 °C in the presence of a catalytic amount of Na[Ph₂CO] furnishes two triruthenium complexes [Ru₃(CO)₁₀{P(C₄H₃O)₃}₂] (1) and [Ru₃(CO)₉{P(C₄H₃O)₃}₃] (2) with the ligand coordinated through the phosphorus atom. Treatment of 1 and 2 with Me₃NO at 40 °C affords the dinuclear phosphido-bridged complexes [Ru₂(CO)₆(μ-η¹,η²-C₄H₃O){μ-P(C₄H₃O)₂}] (3) and [Ru₂(CO)₅(μ-η¹,η²-C₄H₃O){μ-P(C₄H₃O)₂}{P(C₄H₃O)₃}] (4), respectively, that are formed via phosphorus–carbon bond cleavage of a coordinated phosphine followed by coordination of the dissociated furyl moiety to the diruthenium center in a σ,π-alkenyl mode. Reaction of [Ru₃(CO)₁₂] with tri(2-furyl)phosphine in refluxing benzene gives, in addition to 3 and 4, low yields of the cyclometallated complex [Ru₃(CO)₉{μ-η¹,η¹-P(C₄H₃O)₂(C₄H₂O)}₂] (5). Treatment of 3 with EPh₃ (E = P, As, Sb) at room temperature yields the monosubstituted derivatives [Ru₂(CO)₅(μ-η¹,η²-C₄H₃O){μ-P(C₄H₃O)₂}(EPh₃)] (E = P, 8; E = As, 9; E = Sb, 10). Similar reactions of 3 with P(C₄H₃O)₃, P(OMe)₃ and Bu^tNC yield 4, [Ru₂(CO)₅(μ-η¹,η²-C₄H₃O){μ-P(C₄H₃O)₂}{P(OMe)₃}] (11) and [Ru₂(CO)₅(μ-η¹,η²-C₄H₃O){μ-P(C₄H₃O)₂}(NCBu^t)] (12), respectively. The molecular structures of complexes 3, 4 and 8 have been elucidated by single crystal X-ray diffraction studies. Each complex contains a bridging σ,π-alkenyl group and while in 4 the phosphine is bound to the σ-coordinated metal atom, in 8 it is at the π-bound atom. Protonation of 3 and 4 gives the hydride complexes [(μ-H)Ru₂(CO)₆(μ-η¹,η²-C₄H₃O){μ-P(C₄H₃O)₂}]⁺ (6) and [(μ-H)Ru₂(CO)₅(μ-η¹,η²-C₄H₃O){μ-P(C₄H₃O)₂}{P(C₄H₃O)₃}]⁺ (7), respectively, while heating 3 with dimethylacetylenedicarboxylate (DMAD) in refluxing toluene gives the cyclotrimerization product, C₆(CO₂Me)₆.     

Preparation and characterization of mono-cyclopentadienylvanadium dihalide bis-phosphine complexes; crystal structure of (η5-C5H5)VCL2(PMe3)2

Mono-cyclopentadienyl complexes CpVX₂(PR₃)₂ and Cp′VX₂ (PR₃)₂ (Cp = η⁵- C₅H₅; Cp′ = η⁵-C₅H₄Me; R = Me, Et; X = Cl, Br) have been prepared by reaction of VX₃(PR₃)₂ with CpM (M = Na, T1, SnBuⁿ3, 1/2 Mg) or Cp′Na. Attempts to prepare analogous complexes with other phosphine ligands, PPh₃, PPh₂ Me, PPhMe₂, Pcy₃, DMPE and DPPE failed. Reduction of CpVCl₂(PEt₃)₂ with zinc or aluminium under CO (1 bar) offers a simple method for the preparation of CpV(CO)₃(PEt₃). The crystal structure of the trimethylphosphine complex CpVCl₂(PMe₃)₂ is reported.     

Carbonyl substitution of the dicobalt-iron complex (μ3-S)FeCo2(CO)9 with monophosphane or diphosphane ligands

Eight new dicobalt-iron clusters have been synthesised and structurally characterized. Treatment of (μ₃-S)FeCo₂(CO)₉ (A) with monophosphane ligands tris(4-fluorophenyl)phosphane, tris(4-methoxyphenyl)phosphane, or tris(2-furyl)phosphane in the presence of Me₃NO?2H₂O afforded monosubstituted complexes (μ₃-S)FeCo₂(CO)₈L [L = P(4-C₆H₄F)₃, 1; P(4-C₆H₄OMe)₃, 3; P(2-C₄H₃O)₃, 5] and disubstituted complexes (μ₃-S)FeCo₂(CO)₇L₂ [L = P(4-C₆H₄F)₃, 2; P(4-C₆H₄OMe)₃, 4; P(2-C₄H₃O)₃, 6]. Reaction of complex A with Ph₂PN[CH(CH₃)₂]PPh₂ in refluxing toluene gave complex (μ₃-S)FeCo₂(CO)₇{Ph₂PN[CH(CH₃)₂]PPh₂} (7) with an intramolecular bridging diphosphane ligand. Reaction of complex A with trans-1,2-bis(diphenylphosphino)ethylene (trans-dppv) and Me₃NO?2H₂O yielded complex [(μ₃-S)FeCo₂(CO)₈]₂(trans-Ph₂PCH = CHPPh₂) (8) with an intermolecular bridging diphosphane ligand. The new complexes 1–8 were characterized by elemental analysis, IR, ¹H NMR, ³¹P{¹H} NMR, and ¹³C{¹H} NMR spectroscopy, particularly for 1, 3, and 6–8 by X-ray crystallography.