The synthesis and reactivity of some indenyl and bis-indenyl ruthenium carbonyl complexes

The reaction of [Ru₃(CO)₁₂] (1), with indene in refluxing xylene affords [{(η⁵-C₉H₇)Ru(CO)₂}₂] (2), in high yield. An analogous reaction of 1 with 2-phenylindene affords the expected dinuclear complex [{(η⁵-C₉H₆Ph)Ru(CO)₂}₂] (5), and a heptaruthenium cluster [(C₉H₄Ph)Ru₇(μ-H)(μ-CO)₂(CO)₁₆] (6). The indenyl ligand in compound 6 exhibits a novel bonding mode in which the benzenoid ring is μ₄,η¹:η¹:η²:η² bound to the cluster. Refluxing 1 with bis-indenyl methane affords the dinuclear complex [Ru₂(CO)₄{μ-(η⁵-C₉H₆)₂CH₂}] (7), which reacts with iodine via Ru-Ru bond cleavage to give [Ru₂I₂(CO)₄{(η⁵-C₉H₆)₂CH₂}] (8).     

Dppm-substituted ruthenium clusters with capping sulfido and selenido ligands derived from thiourea, tetramethylthiourea and elemental selenium

Treatment of [Ru₃(CO)₁₀(μ-dppm)] (4) [dppm = bis(diphenylphosphido)methane] with tetramethylthiourea at 66 °C gave the previously reported dihydrido triruthenium cluster [Ru₃(μ-H)₂(μ₃-S)(CO)₇(μ-dppm)] (5) and the new compounds [Ru₃(μ₃-S)₂(CO)₇(μ-dppm)] (6), [Ru₃(μ₃-S)(CO)₇(μ₃-CO)(μ-dppm)] (7) and [Ru₃(μ₃-S){η¹-C(NMe₂)₂}(CO)₆(μ₃-CO)(μ-dppm)] (8) in 6%, 10%, 32% and 9% yields, respectively. Treatment of 4 with thiourea at the same temperature gave 5 and 7 in 30% and 10% yields, respectively. Compound 7 reacts further with tetramethylthiourea at 66 °C to yield 6 (30%) and a new compound [Ru₃(μ₃-S)₂{η¹-C(NMe₂)₂}(CO)₆(μ-dppm)] (9) (8%). Thermolysis of 8 in refluxing THF yields 7 in 55% yield. The reaction of 4 with selenium at 66 °C yields the new compounds [Ru₃(μ₃-Se)(CO)₇(μ₃-CO)(μ-dppm)] (10) and [Ru₃(μ₃-Se)(μ₃-η³-PhPCH₂PPh(C₆H₄)}(CO)₆(μ-CO)] (11) and the known compounds [Ru₃(μ-H)₂(μ₃-Se)(CO)₇(μ-dppm)] (12) and [Ru₄(μ₃-Se)₄(CO)₁₀(μ-dppm)] (13) in 29%, 5%, 2% and 5% yields, respectively. Treatment of 10 with tetramethylthiourea at 66 °C gives the mixed sulfur-selenium compounds [Ru₃(μ₃-S)(μ₃-Se)(CO)₇(μ-dppm)] (14) and [Ru₃(μ₃-S)(μ₃-Se){η¹-C(NMe₂)₂}(CO)₆(μ-dppm)] (15) in 38% and 10% yields, respectively. The single-crystal XRD structures of 6, 7, 8, 10, 14 and 15 are reported.     

Reactions of 1,8-bis(diphenylphosphino)naphthalene with Os3(CO)12: C-H and C-P bond cleavage reactions

Reactions of Os₃(CO)₁₂ with 1,8-bis(diphenylphosphino)naphthalene (dppn) are described. Crystallographically characterised complexes isolated from a reaction carried out in refluxing toluene are Os₃(μ-H)₂{μ-PPh₂(nap)PPh(C₆H₄)}₂(CO)₆ (1), Os₃(μ-H){μ₃-PPh₂(nap)PPh(C₆H₄)}(CO)₈ (2) and Os₂(μ-PPh₂){μ-PPh₂(nap)}(CO)₅ (3) (nap=1,8-C₁₀H₆), while at r.t. in the presence of ONMe₃, only Os₃(CO)₁₁{PPh₂(1-C₁₀H₇)} (4) was isolated. While 1 and 2 contain ligands formed by metallation of a Ph group of dppn, as found also in complexes obtained from dppn and Ru₃(CO)₁₂, ligands in 3 and 4 are formed by cleavage of a P-nap bond, not found in the Ru series.     

Synthesis and structure of sulfur and selenium capped dihydride triruthenium clusters [Ru3(CO)7(μ-H)2(μ-dppm)(μ3-E)] (E = S, Se)

Reaction of [Ru₃(CO)₁₀(μ-dppm)] (1) with H₂S at 66 °C affords high yields of the sulfur-capped dihydride [Ru₃(CO)₇(μ-H)₂(μ-dppm)(μ₃-S)] (2), formed by oxidative-addition of both hydrogen-sulfur bonds. Hydrogenation of [Ru₃(CO)₇(μ-dppm)(μ₃-CO)(μ₃-S)] (3) at 110 °C also gives 2 in similar yields, while hydrogenation of [Ru₃(CO)₇(μ-dppm)(μ₃-CO)(μ₃-Se)] (4) affords [Ru₃(CO)₇(μ-H)₂(μ-dppm)(μ₃-Se)] (5) in 85% yield. The molecular structures of 2 and 5 reveal that the diphosphine and one hydride simultaneously bridge the same ruthenium-ruthenium edge with the second hydride spanning one of the non-bridged edges. Both 2 and 5 are fluxional at room temperature being attributed to hydride migration between the non-bridged edges. Addition of HBF₄ to 2 affords the cationic trihydride [Ru₃(CO)₇(μ-H)₃(μ-dppm)(μ₃-S)][BF₄] (6) in which the hydrides are non-fluxional due to the blocking of the free ruthenium-ruthenium edge.     

Ferrocene bridged and substituted tetramethylcyclopentadienyl (or indenyl) carbonyl complexes of iron, ruthenium, and molybdenum

Reactions of ferrocene bridged and substituted tetramethylcyclopentadiene ligands 1,1′-Fc(C₅Me₄H)₂ (1) (Fc = 1,1′-ferrocenediyl) and (C₅H₅FeC₅H₄)C₅Me₄H (5) with Ru₃(CO)₁₂, Fe(CO)₅, and Mo(CO)₃(CH₃CN)₃ in refluxing xylene gave the corresponding trinuclear and tetranuclear complexes Fc[(C₅Me₄)M(CO)]₂(μ-CO)]₂ [M = Ru (2), Fe (3)], Fc[(C₅Me₄)Mo(CO)₃]₂ (4) and [(C₅H₅ FeC₅H₄)C₅Me₄M(CO)]₂(μ-CO)₂ [M = Ru (6), Fe (7)], [(C₅H₅FeC₅H₄)C₅Me₄Mo(CO)₃]₂ (8). Reactions of (3-indenyl)ferrocene (9) with Ru₃(CO)₁₂ or Fe(CO)₅ in refluxing xylene or heptane, also gave the corresponding tetranuclear metal complexes [(C₅H₅FeC₅H₄)C₉H₆M(CO)]₂(μ-CO)₂ [M = Ru (10), Fe (11)]. The molecular structures of 2 and 3 were determined by X-ray diffraction analysis.     

Reactivity of the triruthenium ortho-metalated cluster [Ru3(CO)9{μ3-η,κ,κ-PhP(C6H4)CH2PPh}] with tri(2-thienyl)phosphine and tri(2-furyl)phosphine: Formation of 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine complexes via phosphorus-carbon bond formation

Reaction of [Ru₃(CO)₉{μ₃-η¹,κ¹,κ²-PhP(C₆H₄)CH₂PPh}] (1) with tri(2-thienyl)phosphine (PTh₃) in refluxing THF afforded [Ru₃(CO)₉(PTh₃)(μ-dpbm)] (3) {dpbm = PhP(C₆H₄)(CH₂)PPh} and [Ru₃(CO)₆(μ-CO)₂{μ-κ¹,η¹-PTh₂(C₄H₂S)}{μ₃-κ¹,κ²-Ph₂PCH₂PPh}] (5) in 18% and 12% yields, respectively, while a similar reaction with tri(2-furyl)phosphine (PFu₃) gave [Ru₃(CO)₉(PFu₃)(μ-dpbm)] (4) and [Ru₃(CO)₇(μ-η¹,η²-C₄H₃O)(μ-PFu₂){μ₃-η¹,κ¹,κ²-PhP(C₆H₄)CH₂PPh}] (6) in 24% and 27% yields, respectively. Compounds 2 and 4 are phosphine adducts of 1 in which the diphosphine ligand is transformed into 1,3-diphenyl-2,3-dihydro-1H-1,3-benzodiphosphine (dpbm) via phosphorus-carbon bond formation. Cluster 5 results from metalation of a thienyl ring, the cleaved proton being transferred to the diphosphine. Carbon-phosphorus bond cleavage of a PFu₃ ligand is observed in 6 to afford a phosphido-bridge and a furyl fragment, the latter bridging in a σ,π-vinyl fashion. The molecular structures of 3, 5 and 6 have been determined by X-ray diffraction studies.     

Synthesis and structures of the silyl bridged bis(indenyl) diruthenium complexes and a novel indenyl nonanuclear ruthenium cluster Ru9(μ6-C)(CO)14(μ3-η:η:η-C9H7)2

Thermal treatment of C₉H₇SiMe₂C₉H₇ and C₉H₇Me₂SiOSiMe₂C₉H₇ with Ru₃(CO)₁₂ in refluxing xylene gave the corresponding diruthenium complexes (E)[(η⁵-C₉H₆)Ru(CO)]₂(μ-CO)₂ [E = Me₂Si (1), Me₂SiOSiMe₂ (2)]. A desilylation product [(η⁵-C₉H₇)Ru(CO)]₂(μ-CO)₂ (3) was also obtained in the latter case. Similar treatment of C₉H₇Me₂SiSiMe₂C₉H₇ with Ru₃(CO)₁₂ gave a novel indenyl nonanuclear ruthenium cluster Ru₉(μ₆-C)(CO)₁₄(μ₃-η⁵:η²:η²-C₉H₇)₂ (5) with carbon-centered tricapped trigonal prism geometry, in addition to the diruthenium complex (Me₂SiSiMe₂)[(η⁵-C₉H₆)Ru(CO)]₂(μ-CO)₂ (4) and the desilylation product 3. Complex 4 can undergo a thermal rearrangement to form the product [(Me₂Si)(η⁵-C₉H₆)Ru(CO)₂]₂ (6). The molecular structures of 1, 2, 4, 5, and 6 were determined by X-ray diffraction.     

Synthesis and structural characterization of mesitylphosphinidene-capped ruthenium and osmium clusters

Thermal reaction of [Ru₃(CO)₁₂] with PH₂Mes (Mes = mesityl) in refluxing toluene afforded mesitylphosphinidene-capped ruthenium carbonyl clusters, [Ru₃(CO)₉(μ-H)₂(μ₃-PMes)] (1), [Ru₃(CO)₈(PH₂Mes)(μ-H)₂(μ₃-PMes)] (2), [Ru₃(CO)₉(μ₃-PMes)₂] (3), [Ru₄(CO)₁₀(μ-CO)(μ₄-PMes)₂] (4), and [Ru₅(CO)₁₀H₂(μ₄-PMes)(μ₃-PMes)₂] (5). All products were fully characterized and structurally confirmed by X-ray crystal structure analysis. Complexes 2-4 were also obtained in high yields by stepwise reaction starting from 1. Fluxional behavior of carbonyl groups was observed in case of 4. Complex 5 reveals a new type of skeletal structure, bicapped-octahedron having μ₃- and μ₄-phosphinidene ligands at the capping positions. Similar reaction of [Os₃(CO)₁₂] with PH₂Mes yielded a phosphido-bridged osmium cluster [Os₃(CO)₁₀(μ-H)(μ-PHMes)] (6) and a phosphinidene-capped cluster [Os₃(CO)₉(μ-H)₂(μ₃-PMes)] (7).     

Synthesis of new heterometallic complexes by tin-sulfur bond cleavage of pySSnPh3 (pySH = pyridine-2-thiol) at triruthenium and triosmium centres

The ruthenium-tin complex, [Ru₂(CO)₄(SnPh₃)₂(μ-pyS)₂] (1), the main product of the oxidative-addition of pySSnPh₃ to Ru₃(CO)₁₂ in refluxing benzene, is [Ru(CO)₂(pyS)(SnPh₃)] synthon. It reacts with PPh₃ to give [Ru(CO)₂(SnPh₃)(PPh₃)(κ²-pyS)] (2) and further with Ru₃(CO)₁₂ or [Os₃(CO)₁₀(NCMe)₂] to afford the butterfly clusters [MRu₃(CO)₁₂(SnPh₃)(μ₃-pyS)] (3, M=Ru; 4, M=Os). Direct addition of pySSnPh₃ to [Os₃(CO)₁₀(NCMe)₂] at 70 °C gives [Os₃(CO)₉(SnPh₃)(μ₃-pyS)] (5) as the only bimetallic compound, while with unsaturated [Os₃(CO)₈{μ₃-PPh₂CH₂P(Ph)C₆H₄}(μ-H)] the previously reported [Os₃(CO)₈(μ-pyS)(μ-H)(μ-dppm)] (6) and the new bimetallic cluster [Os₃(CO)₇(SnPh₃){μ-Ph₂PCH₂P(Ph)C₆H₄}(μ-pyS)[(μ-H)] (7) are formed at 110 °C. Compounds 1, 2, 4, 5 and 7 have been characterized by X-ray diffraction studies.     

Synthesis, characterization and electrochemistry of diruthenium complexes linked by aryl acetylide bridges

The reactions between Ru₂(ap)₄Cl and the appropriate lithiated aryl acetylene resulted in the complexes Ru₂(ap)₄(CC4-C₆H₄CCX) with X as SiMe₃ (1), H (2) and Ru₂(ap)₄ (3), 1,3-[Ru₂(ap)₄(CC)]₂(C₆H₄) (4), 1,3-[{Ru₂(ap)₄(CC)}₂]C₆H₃5-CCH (5) and 1-[Ru₂(ap)₄(CC)]C₆H₃3,5-(CCH)₂ (6), where ap is 2-anilinopyridinate. The spectroscopic and electrochemical properties of the new complexes have been assessed. Complexes 3, 4 and 6 display two-electron oxidation and reductions, implying the absence of any significant electronic interaction between the two Ru₂(ap)₄ units in these complexes.     

Diruthenium(I,I) saccharinate complexes: Synthesis, molecular structure, and evaluation as catalysts for carbenoid reactions of diazoacetates

The dinuclear ruthenium complexes [Ru₂(μ-sac)₂(CO)₆] (1), [Ru₂(μ-sac)₂(CH₃CN)₂(CO)₄] (3), [Ru₂(μ-sac)₂(CO)₅(PPh₃)] (4) and [Ru₂(μ-sac)₂(CO)₄(PPh₃)₂] (5) as well as the tetranuclear ruthenium complex [Ru₂(μ-sac)₂(CO)₅]₂ (2) (sac = saccharinate, C₇H₄NO₃S⁻) were synthesized starting from Ru₃(CO)₁₂ and saccharin. X-ray crystal structure analysis of 1, 3A × p-xylene, 4 × CH₂Cl₂ and 5 × 3CH₂Cl₂ showed that the core is bridged through the amidate moieties of the two saccharinate ligands, with a head-tail arrangement in complexes 1, 3A and 5, and a head-head arrangement in 4. For complex 3, an equilibrium mixture of the head-head regioisomer 3A and a second species 3b exists in solution. Complexes 1 and 2 are suitable catalysts for the cyclopropanation of nucleophilic alkenes (styrene, cyclohexene and 2-methyl-2-butene) with methyl diazoacetate.     

Ruthenium carbonyl clusters containing PMe2(nap) and derived ligands (nap = 1-naphthyl): generation of naphthalyne derivatives

Bis(dimethylphosphino)naphthalene, 1,8-(PMe₂)₂C₁₀H₆ (dmpn), reacts readily with Ru₃(CO)₁₂ or Ru₃(μ-dppm)(CO)₁₀ with replacement of one of the PMe₂ groups by H to give Ru₃(CO)_12 − n{PMe₂(nap)}_n (n = 1 2, 2 3) or Ru₃(μ-dppm)(CO)₉{PMe₂(nap)} 4; the complex Ru₃(CO)₁₀(dmpn) 1 is obtained only in small amount. Thermolysis of 2 or 4 gives Ru₃(μ-H)₂{μ₃-PMe₂(C₁₀H₅)}(μ-dppm)_n (CO)_8-2n (n = 0 5, 1 6, respectively) containing μ₃-naphthalyne groups.     

Synthesis of homo- and heteronuclear ruthenium-gold clusters with diphosphine and thiolato bridged ligands. Single crystal molecular structure of [Ru3(CO)10(μ-AuPPh3)(μ-SC5H4N)] and [Ru3(CO)8(μ-H)(μ-SC5H4N)(μ-dppe)]

The reaction between [Ru₃(CO)₁₀(NCMe)₂] and [AuClPPh₃] gave compound [Ru₃(CO)₁₀(μ-Cl)(μ-AuPPh₃)] (1) in quantitative yield under very mild conditions. The reaction of 1 with 4-mercaptopyridine (4-pyS) using ultrasonic reaction conditions gave the heteronuclear compound [Ru₃(CO)₁₀(μ-AuPPh₃)(μ-SC₅H₄N)] (2) in moderate yield. There was no spectroscopic evidence that indicates the formation of the hydride isolobal analog in this reaction. The homonuclear cluster [Ru₃(CO)₈(μ-H)(μ-SC₅H₄N)(μ-dppe)] (3) was prepared by a selective reaction employing the ruthenium-diphosphine derivative [Ru₃(CO)₁₀(μ-dppe)] (dppe = 1,2-bis(diphenylphosphine)ethane) with 4-pyS in THF solution. The isolobal analog to compound 3, compound [Ru₃(CO)₈(μ-AuPPh₃)(μ-SC₅H₄N)(μ-dppe)] (4) was synthesized by the reaction between compound 2 and dppe in refluxing dichloromethane. Compounds 1-4 were characterized in solution by spectroscopic methods and the molecular structure of compounds 2 and 3 in the solid state was obtained by single crystal X-ray diffraction studies.     

Reaction of the heteronuclear cluster RuOs3(μ-H)2(CO)13 with toluene

The heteronuclear cluster RuOs₃(μ-H)₂(CO)₁₃ (4) reacts with refluxing toluene to form the clusters Ru₂Os₃(μ-H)₂(CO)₁₆ (5) RuOs₃(CO)₉(μ-CO)₂(η⁶-C₆H₅Me) (6) and Ru₂Os₃(CO)₁₂(μ-CO)(η⁶-C₆H₅Me) (7). Cluster 5 exists as a mixture of five isomers. The inter-relationship among the clusters has also been investigated.     

Unsymmetrical alkyne binding to a triruthenium centre: Oxidative-addition of diphenyl ditelluride to the furyne cluster [Ru3(CO)7(μ-H)(μ3-η-C4H2O){μ-P(C4H3O)2}(μ-dppm)]

Oxidative-addition of PhTe₂Ph to the furyne cluster [Ru₃(CO)₇(μ-H)(μ₃-η²-C₄H₂O){μ-P(C₄H₃O)₂}(μ-dppm)] (1) results in the isolation of four complexes; (i) the previously reported 54-electron cluster [Ru₃(CO)₆(μ₃-Te)₂(μ-TePh)₂(μ-dppm)] (5) which results from elimination of trifuryl phosphine, (ii) the furenyl cluster [Ru₃(CO)₅(μ-η²-C₄H₃O){μ-P(C₄H₃O)₂}(μ-TePh)₂(μ-dppm)] (6) which results from carbon-hydrogen bond formation and (iii) two new 50-electron complexes [Ru₃(CO)₅(μ-H)(μ₃-η²-C₄H₂O){μ-P(C₄H₃O)₂}(μ-TePh)₂(к²-dppm)] (7) and [Ru₃(CO)₄(μ-H){P(C₄H₃O)₃}(μ₃-η²-C₄H₂O){μ-P(C₄H₃O)₂}(μ-TePh)₂(к²-dppm)] (8) both containing unsymmetrical furyne ligands. The structures of all the new compounds have been unambiguously established by single crystal X-ray crystallography. Further reactivity studies have provided a clear understanding of the relative sequence of the key oxidative-addition and reductive-elimination processes, showing that 6 is an intermediate in the formation of 7. DFT calculations have been used to shed light on the unsymmetrical binding of the furyne ligand in 7 and also to show that the adopted position of the heteroatom within the furyne ring can vary within complexes of this type.     

Synthesis and characterization of triosmium and triruthenium pyrene clusters

The reaction between 1-pyrenecarboxaldehyde (C₁₆H₉CHO) and the labile triosmium cluster [Os₃(CO)₁₀(CH₃CN)₂] gives rise to the formation of two new compounds by competitive oxidative addition between the aldehydic group and an arene C-H bond, to afford the acyl complex [Os₃(CO)₁₀(μ-H)(μ-COC₁₆H₉)] (1) and the compound [Os₃(CO)₁₀(μ-H) (C₁₆H₈CHO)] (2), respectively. Thermolysis of [Os₃(CO)₁₀(μ-H)(μ-C₁₆H₉CO)] (1) in n-octane affords two new complexes in good yields, [Os₃(CO)₉(μ-H)₂(μ-COC₁₆H₈)] (3) and the pyryne complex [Os₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (4).In contrast, when 1-pyrenecarboxaldehyde reacts with [Ru₃(CO)₁₂] only one product is obtained, [Ru₃(CO)₉(μ-H)₂(μ₃-η¹:η¹:η²-C₁₆H₈)] (5), a nonacarbonyl cluster bearing a pyrene ligand. All compounds were characterized by analytical and spectroscopic data, and crystal structures for 1, 2, 4 and 5 were obtained.     

Synthesis and X-ray structure study on new Au(I) polymer architectures based on multi-sulfur tentacles

Multi-thiolate ligands are used as a scaffold to construct a series of supramolecules, which cover the following entries; [(1,3-S₂-C₆H₄){AuP(C₆H₄-3-CF₃)₃}₂]_n (1), [(1,4-S₂-C₆H₄){AuP(C₆H₄-3-CF₃)₃}₂]_n (2), (1,4-S₂-C₆H₄){AuP(C₆H₅)₂(2-pyridine)}₂ (3), [(1,3,5-S₃-C₆H₃){AuP(C₆H₅)₂(2-pyridine)}₃]_n (4), and [(1,3,5-S₃-C₆H₃){AuP(C₆H₄-3-CF₃)₃}₃]_n (5). The molecular and crystal structures of these new derivatives have been elucidated by single crystal X-ray diffraction. Aurophilic interactions have been demonstrated for 1, 2, 4, and 5 to produce new supramolecular architectures. Nano-channels are formed by aurophilic and π-π interactions for 1, in which benzene molecules are trapped. An 8 (eight)-shaped loop is formed in solid state for 2. Infinite zigzag chains are constructed for 4 and 5.     

Synthesis, structures and comparative electrochemical study of 2,5-bis(trimethylsilylethynyl)thiophene coordinated cobalt carbonyl units

The reaction between 2,5-bis(trimethylsilylethynyl)thiophene and Co₂(CO)₈ or Co₂(CO)₆(X), (X = dppa, dppm), gave rise to the formation of substituted ethynylcobalt complexes containing one or two Co₂(CO)₆ or Co₂(CO)₄(X) units, 2-[Co₂(CO)₄(X){μ₂-η²-(SiMe₃)C₂}]-5-(Me₃SiCC)C₄H₂S (X = 2CO (1), dppa (3) or dppm (4)) and 2,5-[Co₂(CO)₄(X){μ₂-η²-SiMe₃C₂}]₂C₄H₂S (X = 2CO (2), dppa (5) or dppm (6)). Desilylation of the non-metallated and metallated alkynes in 3, 4 and 6 occurred on treatment with KOH and tetrabutylammonium fluoride to give 2-[Co₂(CO)₄(μ-X){μ₂-η²-SiMe₃C₂}]-5-(CCH)C₄H₂S (X = dppa (7), dppm (8)) and 2,5-[Co₂(CO)₄(μ-dppm){μ₂-η²-HC₂}]₂C₄H₂S (9), respectively. Crystals of 6 suitable for single-crystal X-ray diffraction were grown and the molecular structure of this compound is discussed. A comparative electrochemical study of all these complexes is presented by means of the cyclic and square-wave voltammetry techniques.     

Two modes of C-H bond activation of tris(2-thienyl)phosphine in trinuclear osmium carbonyl clusters

Tris(2-thienyl)phosphine, P(C₄H₃S)₃, reacts with [Os₃(CO)₁₂] at 110 °C to give the phosphine-substituted derivatives [Os₃(CO)₁₁{P(C₄H₃S)₃}] (1), [Os₃(CO)₁₀{P(C₄H₃S)₃}₂] (2) and [Os₃(CO)₉{P(C₄H₃S)₃}₃] (4), as well as the C-H activated product [Os₃(μ-H)(CO)₉{μ-P(C₄H₂S)(C₄H₃S)₂}{P(C₄H₃S)₃}] (3), in which the bridging ligand is equatorially coordinated to two osmium atoms. Thermolysis of 2 in refluxing toluene results in the formation of 3. Compound 1 can also be prepared in high yield from [Os₃(CO)₁₁(NCMe)]. The reaction of [Os₃(μ-H)₂(CO)₁₀] with tris(2-thienyl)phosphine at room temperature afforded [Os₃(μ-H)₂(CO)₉{P(C₄H₃S)₃}] (5) and [Os₃H(μ-H)(CO)₁₀{P(C₄H₃S)₃}] (6), with the ligand coordinated through the phosphorus atom whereas at elevated temperature the cyclometallated compounds [Os₃(μ-H)(CO)₉{μ₃-P(C₄H₂S)(C₄H₃S)₂}] (7) and [Os₃(μ-H)(CO)₈{μ₃-P(C₄H₂S)(C₄H₃S)₂{P(C₄H₃S)₃}] (8) were obtained in addition to 5. Heating 6 in refluxing heptane furnished 5 via loss of one carbonyl ligand. Thermolysis of 1 and 3 in refluxing toluene gives 7 and 8, respectively, in good yields. In 3, the μ-P(C₄H₂S)(C₄H₃S)₂ ligand is coordinated through the phosphorus to one Os atom and through a σ-Os-C bond to the second osmium atom. Compound 7 contains the μ₃-P(C₄H₂S)(C₄H₃S)₂ ligand bound through phosphorus to one Os atom, through a σ-Os-C bond to another and by an η² (π)-interaction to the third osmium atom. Compounds 1, 2 and 4 contain the ligand coordinated exclusively through the phosphorus atom. The crystal and molecular structures of 2, 3, 5, 6 and 7 are reported.     

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.