Mixed-metal Carbonyl Clusters Research Articles

Routes to Higher Nuclearity Mixed-Metal Carbonyl Clusters Using the [Rh(η5-C5Me5)(NCMe)3]2+ Dication as a Building Block

Reaction of the [Rh(η5-C5Me5)(NCMe)3]2+ (1) dication with the hexaosmium [Os6(CO)17]2− (2) dianion leads to the initial formation of [Os6(CO)17Rh(η5-C5Me5)] (3). This cluster readily adds CO to form [Os6(CO)18Rh(η5-C5Me5)] (4) which has been characterised crystallographically. 3 also adds dihydrogen to give [Os6H2(CO)17Rh(η5-C5Me5)] (5) and undergoes a substitution reaction with PPh3 to form [Os6(CO)16(PPh3)Rh(η5-C5Me5)] (6). With the [Ru6(CO)18]2− (7) dianion, [Rh(η5-C5Me5)(NCMe)3]2+ (1) reacts to form three mixed-metal clusters [Ru5(CO)15Rh(η5-C5Me5)] (8), [Ru6(CO)18Rh(η5-C5Me5)] (9) and [Ru6(CO)18Rh2(η5-C5Me5)2] (10). The clusters have been characterised spectroscopically and the structures of 8 and 10 have been confirmed crystallographically. The cluster 8 undergoes a substitution reaction with P(OMe)3 to form the disubstituted product [Ru5(CO)13(P(OMe)3)2Rh((η5-C5Me5)] (11) which has also been characterised crystallographically.

TDDFT study on electronic excitations and first hyperpolarizabilities of mixed-metal carbonyl clusters MonIr4-n(μ-CO)3(β5-Cp)n (n = 1,2,3)

A series of mixed-metal carbonyl clusters, MonIr4-n(μ-CO)3(CO)9-n(η5-Cp)n (n = 1, 2; Cp = C5H4Me, C5HMe4, C5Me5, C5H5), have been investigated using the TDDFT method. The results estimated the medium magnitude of the first static hyperpolarizabilities (β tot ∼ 2 × 10−30esu) of these tetrahedral mixed-metal clusters, most of which originate from the intra-cluster charge transfer of the metal skeleton consisting of polar metal–metal interactions. No direct contributions of the Cp ligands to the relevant charge transfer were found, but the cooperative effect between the metal centres and Cp ligands impacts the β. Based on these studies a mixed-metal cluster Mo3Ir(μ-CO)3(CO)7(η5-Cp)2 was designed that exhibits enhanced first hyperpolarizability.

New High Nuclearity Platinum−Ruthenium Carbonyl Cluster Complexes Containing a Phenylacetylene Ligand: Structures and Properties

Reaction of the mixed-metal carbonyl cluster complex Ru 5 (CO) 1 5 (C)[Pt(PBu t 3 )], 3, with PhC 2 H yielded the new compound PtRu 5 (CO) 1 3 (PBu t 3 )(μ 5 -C)(μ 3 -PhC 2 H), 4, in 41% yield. Two new bimetallic cluster complexes,Pt 2 Ru 5 (CO) 1 3 (PBu t 3 ) 2 (μ 5 -C)(μ 3 -PhC 2 H), 5, and Pt 3 Ru 5 (CO) 1 3 -(PBut 3 ) 3 (μ 5 -C)(μ 3 -PhC 2 H), 6, were subsequently obtained in 44% and 40% yield, respectively, from the reaction of 4 with an excess of Pt(PBu t 3 ) 2 . All products were characterized crystallographically by single-crystal X-ray diffraction techniques. The structure of 4 consists of a square-pyramidal cluster of five ruthenium atoms with a Pt(PBu t 3 ) group capping one of the Ru 3 triangles. A PhC 2 H ligand bridges one of the PtRu 2 triangles. Compounds 5 and 6 are similar to 4 but have in addition one and two Pt(PBu t 3 ) groups bridging one and two edges of the Ru 5 square-pyramidal portion of the cluster. Compound 6 was shown to be dynamically active on the 3 1 P NMR time scale by a process that involves an interchange of two of its inequivalent Pt(PBu t 3 ) groups.

Ligand substitution reaction in the parent cluster (μ 3-FcCHC)FeCo 2(CO) 9 and structural characterization of its CO substituted derivatives

The new mixed metal carbonyl clusters (μ 3-FcCHC)FeCo 2(CO) 7dppm (Fc = C 5H 5FeC 5H 4, ferrocenyl; dppm = Ph 2PCH 2PPh 2) ( 1), (μ 3-FcCHC)FeCo 2(CO) 8L [L = PPh 3 ( 2); AsPh 3 ( 3)] and (μ-FcC CH)Co 2(CO) 5PPh 3 ( 4) have been synthesized by facile substituted reactions. The crystal and molecular structures of 1, 2 and 3 have been determined by single crystal X-ray analysis; the ligand dppm replaces two equatorial carbonyls from two Co(CO) 3 groups in the FeCo 2 core, and the ligands PPh 3 and AsPh 3 replace one equatorial carbonyl from a Co(CO) 3 group. The new compounds were characterized by IR, 1H, 13C, 31P (for 1, 2) NMR and MS. The electrochemical properties for 1, 2, 3 and 5 were investigated and the results show that the replacement of CO alters the electron density on the cluster core FeCo 2 leading to a variety of interactions between FeCo 2 and the apical FcCHC, and making the Fe of the ligand FcCHC in clusters 1, 2 and 3 turn into a redox center.

Novel Rh–Mn mixed-metal carbonyl cluster containing μ 3 and μ-bridging carbyne ligands, [(μ 3-CC 6H 5)(μ-CC 6H 5)Rh 2Mn 2Cp 2(μ-CO) 3(CO) 3]: structure, electrochemistry and catalytic properties

The cationic carbyne complex [Cp(CO) 2MnCC 6H 5]BBr 4 ( 1) reacts with PPN[Rh(CO) 4] ( 2) to give the title cluster [(μ 3-CC 6H 5)(μ-CC 6H 5) Rh 2Mn 2Cp 2(μ-CO) 3(CO) 3] ( 3) whose structure has been determined by X-ray diffraction. The electrochemical properties of 3 have been investigated using cyclic voltammetric method. At 60 °C and 2.0 MPa of initial total CO/H 2 (1:1) pressure, the catalytic activity of 3 towards hydroformylation of styrene has also been checked.

Iron-Iridium Mixed-Metal Carbonyl Clusters: A Mössbauer Study of the Structure and of the Adsorption of [Fe2Ir2(CO)12]2- on MgO

193Ir and 57Fe Mossbauer spectroscopy was used to investigate the structure of the [Fe2Ir2(CO)12]2- cluster compound and the adsorption of this cluster on hydrated MgO. Supported samples were prepared by impregnation of the magnesia with solutions of [Et4N]2[Fe2Ir2(CO)12] in acetone. The Mossbauer and FT-IR spectra of the MgO-supported cluster confirm that the bimetallic carbonyl is molecularly physisorbed onto MgO without undergoing any transformation or decomposition. The easy solvent extraction of the intact cluster from the oxide surface excludes ion pairing between the cluster anion and the Mg2+ surface sites. Mossbauer spectra are in agreement with the refined structure of the molecular cluster and the temperature dependence of the 57Fe Mossbauer spectra above 80 K is consistent with the low degree of interaction of the cluster with the support. This technique, therefore, appears to be promising in order to infer structural information when X-ray determination fails.

Synthesis and characterization of high-nuclearity iridium–ruthenium and –gold mixed-metal carbonyl clusters, [Ir7Ru3(CO)23]−, [Ir7Ru3(CO)23(AuPPh3)] and [Ir6Ru3(CO)21(AuPPh3)]−, possessing tetrahedrally capped octahedral iridium cores obtained by capping reactions with [Ru3(CO)12] and [AuCl(PPh3)

The new carbonyl cluster [PPh4][Ir7Ru3(CO)23] 1 has been obtained by the high yield reaction of [PPh4]2[Ir6(CO)15] with [Ru3(CO)12] in the presence of p-toluenesulfonic acid. The monoanionic decanuclear cluster 1 has an octahedral arrangement of the iridium atoms with three ruthenium atoms and an iridium atom tetrahedrally capping four triangular faces. Two terminal CO ligands are bound to each iridium atom and three to each ruthenium atom. In this synthesis p-toluenesulfonic acid served as a degradation reagent for [Ir6(CO)15]2− to generate the capping {Ir(CO)2}+ moiety. Reaction of 1 with [AuCl(PPh3)] in the presence of AgOSO2CF3 at ambient temperature yielded the undecanuclear neutral cluster [Ir7Ru3(CO)23(AuPPh3)] 2. The {AuPPh3}+ group co-ordinates to the apical iridium atom of the parent metal carbonyl monoanion 1 maintaining the cluster framework as well as the stereogeometry of the CO ligands. Thermal treatment of 1 with [AuCl(PPh3)] in refluxing 1,2-dichloroethane caused substitution of the capping {Ir(CO)2}+ group in 1 with an isolobal {AuPPh3}+ group, resulting in the formation of decanuclear monoanionic cluster [PPh4][Ir6Ru3(CO)21(AuPPh3)] 3.

The mixed-metal carbonyl cluster anion [Os 3Ir(CO) 13] −: synthesis, structure, reactivity and catalytic activity in the carbonylation of methanol

The cluster anion [Os 3Ir(CO) 13] − ( 1) was prepared in 50% yield by reaction of Os 3(CO) 12 with [Ir(CO) 4] −. The single-crystal X-ray structure analysis of the bis(triphenylphosphoranylidene)ammonium salt shows 1 to consist of a tetrahedral metal core with one of the 13 carbonyl ligands being bridging. Protonation of 1 led to the neutral cluster HOs 3Ir(CO) 13 ( 2), whereas the hydrogenation gave the cluster anion [H 2Os 3Ir(CO) 12] − ( 3). The catalytic activity of 1 for the carbonylation of methanol was studied. Using CH 3I as co-catalyst, catalytic turnover numbers up to 1800 were obtained (140°C, 30 bar) within 14 h.

Site-selective carbonyl substitution in the mixed-metal cluster anion [H2Ru3Ir(CO)12]−: synthesis and characterization of phosphine, phosphite, arsine and stibine derivatives

The reaction of the mixed-metal carbonyl cluster anion [H2Ru3Ir(CO)12]− with PPh3, PMe3, P(OPh)3, AsPh3 or SbPh3 leads to the mono-substituted derivatives [H2Ru3Ir(CO)11L]− (L=PPh31, L=PMe32, L=P(OPh)33, L=AsPh34, L=SbPh35). Protonation of the anions 1–5 gives the neutral trihydrido derivatives H3Ru3Ir(CO)11L (L=PPh36, L=PMe37, L=P(OPh)38, L=AsPh39, L=SbPh310). All new tetranuclear clusters invariably show a tetrahedral arrangement of the Ru3Ir skeleton, as predicted for 60 e systems. The ligand L is coordinated to one of the ruthenium atoms, except in the case of L=PMe3 where two substitution isomers are observed. While the anionic isomers [H2Ru3Ir(CO)11(PMe3)]− (2) could not be separated, the corresponding neutral isomers H3Ru3Ir(CO)11(PMe3) (7) could be resolved by thin-layer chromatography. In isomer 7a, the phosphine ligand is coordinated to one of the ruthenium atoms, whereas in isomer 7b the PMe3 ligand is bonded to the iridium atom. The molecular structures of 1,7b,8 and 9 were confirmed by a single-crystal X-ray structure analysis.

High-nuclearity mixed-metal carbonyl clusters of osmium and palladium; molecular structures of [Os5Pd6(CO)13(µ-CO)5(µ-H)2(µ-dppm)2] ·2CH2Cl2·C6H14 and [Os5Pd6(CO)13(µ-CO)6(µ-dppm)2

The high-nuclearity mixed-metal carbonyl clusters [Os5- Pd6(CO)13(µ-CO)5(µ-H)2(µ-dppm)2] 1 and [Os5Pd6(CO)13- (µ-CO)6(µ-dppm)2] 2 are synthesized from the reaction of [Os3(CO)10(µ-H)2] with [Pd2(µ-dppm)2Cl2]; their molecular structures are determined by X-ray analysis.

Synthesis and characterization of high-nuclearity osmium–rhodium mixed-metal carbonyl clusters; molecular and crystal structures of [Os12Rh9(CO)44(μ3-Cl)]·2CH2Cl2 and [Os4Rh3(μ3-H)(CO)14(μ3-CO)(η4-C7H8)2

The anionic triosmium cluster [N(PPh3)2][Os3(µ-H)(CO)11] reacts with [Rh(nbd)Cl)2 (nbd = norbornadiene) in the presence of AgPF6 to give two new high-nuclearity osmium–rhodium clusters [Os12Rh9(CO)44(µ3-Cl)] 1 and [Os4Rh3(µ3-H)(CO)14(µ3-CO)(η4-C7H8)2] 2 in moderate yields.

The chemistry of palladium–osmium mixed-metal carbonyl clusters

The chemistry of palladium–osmium mixed-metal carbonyl clusters

Preparation and crystal structure of [( η5-C 5H 4CH 3)MoFeCo(CO) 6( μ, η4-Ph 2PCH 2CH 2PPh 2) ( μ3-S)

The mixed-metal carbonyl cluster [( η 5-C 5H 4CH 3)MoFeCo(CO) 6( μ, η 4-Ph 2PCH 2 CH 2PPh 2) ( μ 3-S)] ( 2) has been prepared by the substituent reaction of [( η 5-C 5H 4CH 3) MoFeCo(CO) 8( μ 3-S )] ( 1) with 1, 2-bis(diphenylphosphino)ethane (Ph 2PCH 2CH 2PPh 2). The title cluster has been characterized by elemental analyses, IR and 1H NMR spectroscopy. Its structure, confirmed by X-ray crystallography, shows that the bidentate ligand Ph 2PCH 2CH 2PPh 2 bridges the Fe-Co bond. The result can be used to explain the active catalytic sites on the cluster for hydroformylation.

Unusual mixed metal cluster reactions: Formation of the mixed metal chain Rh 2Ru 3(CO) 10(μ-SEt) 8

The tetranuclear mixed metal carbonyl cluster HRuRh 3(CO) 12 reacts with ethanethiol to give a pentanuclear compound Rh 2Ru 3(CO) 10(μ-SEt) 8 as a minor product. An X-ray diffraction study has revealed that five metal atoms form a thiolate-bridged chain structure without direct metal-bonds. The rhodium atoms end the chain, and each metal has two terminal carbonyl ligands.

Au-Ir and Hg-Ir Mixed-Metal Carbonyl Clusters. Synthesis, Characterization, and Solid State Structure of [Ir6(CO)15(AuPPh3)2] and [Ir6(CO)14(HgCl)2]2-

Au-Ir and Hg-Ir Mixed-Metal Carbonyl Clusters. Synthesis, Characterization, and Solid State Structure of [Ir6(CO)15(AuPPh3)2] and [Ir6(CO)14(HgCl)2]2-

ChemInform Abstract: Organometallic Chemistry and Homogeneous Catalysis of Rhodium and Rhodium‐Cobalt Mixed Metal Carbonyl Clusters

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Iron-iridium mixed-metal carbonyl clusters. 4. Synthesis, characterization, and chemical behavior of [FeIr4(CO)13]2- and [Fe2Ir4(CO)16]2-. Solid-state structures of [PPh4]2[FeIr4(CO)13].C4H8O and [NEt4][NMe3(CH2Ph)][Fe2Ir4(CO)16

The cluster [FeIr 4 (CO) 13 ] 2- is obtained by decarbonylation of [FeIr 4 (CO) 15 ] 2- , either at room temperature or by moderate heating of a solution of the complex. The salt [PPh 4 ] 2 °FeIr 4 (CO) 13 ].C 4 H 8 O crystallizes in the triclinic space group P1

Organometallic chemistry and homogeneous catalysis of Rh and Rh-Co mixed metal carbonyl clusters

The reactions of hydrosilane and/or alkyne as well as isonitriles with rhodium and rhodium cobalt mixed metal carbonyl clusters, e.g., Rh4(CO)12 and Co2Rh2(CO)12, are studied. Novel mixed metal complexes, e.g., CoRh(CO)5 (HC≡CBu n ), (R3Si)2Rh(CO) n Co(CO)4, Rh(R−N≡C)4Co(CO)4, Co2Rh2(CO)10(HC≡CR), and Co2Rh2(CO)9(HC≡CBu n ), are synthesized and identified. The catalytic activities of these rhodium and rhodium-cobalt mixed metal complexes are examined in hydrosilyation, silylformylation, and novel silylcarbocyclization reactions. Possible mechanisms for these reactions are proposed and discussed.

Chemistry of iridium carbonyl cluster complexes. Synthesis, chemical characterization and solid state structure of the mixed-metal carbonyl cluster [PPh 4][Ir 6(μ-CO) 3(CO) 12{μ 3-Cu(NCMe)}] · CH 2Cl 2 and its conversion to the dianion [Ir 12(CO) 26] 2−

The cluster [Ir 6(CO) 15{Cu(NCMe)}] − is obtained by condensation of [Ir 6(CO) 15] 2− with [Cu(NCMe) 4] + at room temperature in tetrahydrofuran. The salt [PPh 4][Ir 6(CO) 15{μ 3-Cu(NCMe)}]. CH 2Cl 2 crystallizes in the monoclinic space group P2 1/ n (non-standard no. 14) with a = 21.146(12), b = 11.512(9), c = 20.450(9) Å, β = 90.58(4)°, and Z = 4; R = 0.038 and R w = 0.041 for 2175 observed reflections having I ≥ 3σ,( I). The monoanion consists of an octahedron of iridium atoms, face-capped by the CuNCMe group, with twelve terminal carbonyls (two for each iridium atom) and three edge-bridging carbonyls. Average distances (Å) and angles are: IrIr, 2.779; IrCu, 2.636; IrC t, 1.82; CO t, 1.18; IrCO t, 173°; IrC b, 2.02; CO b, 1.19; IrCO b, 138° (t = terminal, b = edge-bridging). In solution the mixed metal carbonyl cluster decomposes slightly and slowly by loss of copper metal and formation of the previously reported [Ir 12(CO) 26] 2−.

Comparative study of homogeneous catalytic activity of group 8–9 metal compounds in hydroformylation of 1-hexene

Group 8–9 transition-metal compounds, inorganic chlorides, the corresponding carbonyls, and two mixed-metal carbonyl clusters were studied as homogeneous catalyst precursors in 1-hexene hydroformylation under an equimolar carbon monoxide and hydrogen atmosphere (50 bar) at 100 °C. Of the metals studied, the Co and Rh compounds, both as chlorides and as carbonyls, were the most reactive as 1-hexene hydroformylation catalysts. In addition, Ru 3(CO) 12 showed a modest hydroformylation activity. The regioselectivity, i.e., the ratio of linear to branched products, of the catalysts studied was high for cobalt carbonyls as well as for phosphine- and phosphite-modified rhodium carbonyls and low for binary rhodium carbonyls. The addition of NEt 3 as a co-catalyst into the hydroformylation solution of RhCl 3·3H 2O, Rh 2(CO) 4Cl 2, Rh 4(CO) 12, and Co 2Rh 2(CO) 12 initiated hydrogenation of aldehydes to the corresponding alcohols in high yield (68–100%). A weaker hydrogenation effect was observed in the cases of Ru 3(CO) 12 and [PPN][RuRh 5(CO) 16]. However, the presence of phosphine or phosphite on the rhodium catalyst or in the hydroformylation solution prevented almost completely the effect of the amine as a co-catalyst.