Carbonyl Cluster Complexes Research Articles

Addition of Alkynes to High Nuclearity Platinum–Ruthenium Carbonyl Cluster Complexes

The reactions of the mixed metal cluster complexes PtRu5(CO)16(μ6-C)[Pt(PBu \(^{{\rm t}}_3\))], 5 and PtRu5(CO)16(μ6-C)[Pt(PBu \(^{\rm t}_{3})\)]2, 6 with selected alkynes have been investigated. Compound 5 adds one and two equivalents of PhC2H to yield the new compounds PtRu5(CO)15(μ6-C)(μ3-PhC2H)[Pt(PBu \(^{{\rm t}}_3\))], 8 and PtRu5(CO) \(_{13}(\mu_6\)-C)( \(\mu_3\)-PhC2H)2[Pt(PBu \(^{{\rm t}}_3\))], 9 at 40 and 68°C, respectively. Compound 6 was found to react with PhC2H at 40°C to yield the new compound PtRu5(CO) \(_{16}(\mu_{6}\)-C)( \(\mu_3\)-PhC2H)[Pt(PBu \(^{{\rm t}}_3\))]2, 10. The reaction of 6 with PhC2Ph at 97°C yielded the new compound PtRu5(CO) \(_{12}(\mu_{6}\)-C)( \(\mu_3\)-PhC2Ph)2[Pt(PBu \(^{{\rm t}}_{3}\))]2, 11. All products were characterized crystallographically by single crystal X-ray diffraction techniques. The structure of 8 consists of a pseudo-octahedral PtRu5 cluster with a second platinum atom bridging a basal edge of the Ru5 square pyramid. A triply bridging PhC2H ligand is bonded to the two platinum atoms and one of the ruthenium atoms. The structure of 9 consists of a nido-dodecahedral Pt2Ru5 cluster with a carbido ligand in the interior that is not bonded to all seven of the metal atoms. It also contains two triply bridging PhC2H ligands. The structure of 10 consists of a central octahedral cluster of five ruthenium atoms and one platinum atom. Two additional platinum atoms are bonded to the platinum atom in this cluster but these atoms are not bonded to any other metal atoms of the PtRu5 cluster. A triply bridging PhC2H ligand is coordinated to the group of three platinum atoms. The structure of 11 consists of an octahedral PtRu5 cluster with two additional platinum atoms capping two PtRu2 triangular faces. There are two PhC2Ph ligands bridging two Ru3 triangular faces of the central octahedron.

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.

η2-Edge-Bridging and η3-Face-Capping Coordination of Conjugated Ynenyl Ligands in Triruthenium Carbonyl Cluster Complexes Derived from 1,1-Dimethylhydrazine

The reactions of the 1,1-dimethylhydrazine-derived cluster [Ru 3 (μ-H)(μ 3 -η 2 -HNNMe 2 )(CO 9 ] with conjugated diynes, RC 4 R (R = Me, Ph), afford the ynenyl derivatives [Ru 3 (μ 3 -η 2 -HNNMe 2 )(μ-η 2 -RCCCCHR)(μ-CO) 2 (CO) 6 ] (R = Me) and [Ru 3 (μ 3 -η 2 -HNNMe 2 )(μ 3 -η 3 -RCCCCHR)-(μ-CO)(CO) 7 ] (R = Me, Ph), featuring η 2 -edge-bridging and η 3 -face-capping coordination modes for their ynenyl ligands. DFT calculations have revealed that the face-capped products are slightly more stable than the edge-bridged ones. The regioselectivity of the reactions is affected by the nature of the R groups of the diynes.

Novel rhodium and ruthenium carbonyl cluster complexes with face- and edge-bridging GaCp* ligands. Synthesis and structural characterization of the Rh6(CO)12(µ3-GaCp*)4 and Ru6(η6-C)(µ2-CO)(CO)13(µ3-GaCp*)2(µ2-GaCp*) clusters

Reactions of hexanuclear carbonyl clusters of rhodium Rh(6)(CO)(16) and ruthenium Ru(6)(eta(6)-C)(micro(2)-CO)(CO)(16) with GaCp*(Cp*= C(5)Me(5)) in the mild conditions result in substitution of CO ligands and formation of the Rh(6)(CO)(12)(micro(3)-GaCp*)(4) and the Ru(6)(eta(6)-C)(micro(2)-CO)(CO)(13)(micro(3)-GaCp*)(2)(micro(2)-GaCp*) cluster derivatives.

Edge‐Bridging and Face‐Capping Coordination of Alkenyl Ligands in Triruthenium Carbonyl Cluster Complexes Derived from Hydrazines: Synthetic, Structural, Theoretical, and Kinetic Studies

The reactions of the triruthenium cluster complex [Ru3(mu-H)(mu3-eta2-HNNMe2)(CO)9] (1; H2NNMe2=1,1-dimethylhydrazine) with alkynes (PhC triple bond CPh, HC triple bond CH, MeO2CC triple bond CCO2Me, PhC triple bond CH, MeO2CC triple bond CH, HOMe2CC triple bond CH, 2-pyC triple bond CH) give trinuclear complexes containing edge-bridging and/or face-capping alkenyl ligands. Whereas the edge-bridged products are closed triangular species (three Ru-Ru bonds), the face-capped products are open derivatives (two Ru-Ru bonds). For terminal alkynes, products containing gem (RCCH2) and/or trans (RHCCH) alkenyl ligands have been identified in both edge-bridging and face-capping positions, except for the complex [Ru3(mu3-eta2-HNNMe2)(mu3-eta3-HCCH-2-py)(mu-CO)(CO)7], which has the two alkenyl H atoms in a cis arrangement. Under comparable reaction conditions (1:1 molar ratio, THF at reflux, time required for the consumption of complex 1), some reactions give a single product, but most give mixtures of isomers (not all the possible ones), which were separated. To determine the effect of the hydrazido ligand, the reactions of [Ru3(mu-H)(mu3-eta2-MeNNHMe)(CO)9] (2; HMeNNHMe=1,2-dimethylhydrazine) with PhC triple bond CPh, PhC triple bond CH, and HC triple bond CH were also studied. For edge-bridged alkenyl complexes, the Ru--Ru edge that is spanned by the alkenyl ligand depends on the position of the methyl groups on the hydrazido ligand. For face-capped alkenyl complexes, the relative orientation of the hydrazido and alkenyl ligands also depends on the position of the methyl groups on the hydrazido ligand. A kinetic analysis of the reaction of 1 with PhC[triple chemical bond]CPh revealed that the reaction follows an associative mechanism, which implies that incorporation of the alkyne in the cluster is rate-limiting and precedes the release of a CO ligand. X-ray diffraction, IR and NMR spectroscopy, and calculations of minimum-energy structures by DFT methods were used to characterize the products. A comparison of the absolute energies of isomeric compounds (obtained by DFT calculations) helped rationalize the experimental results.

Superloading of Tin Ligands into Rhodium and Iridium Carbonyl Cluster Complexes

The reactions of Rh4(CO)12 and Ir4(CO)12 with Ph3SnH have yielded the new Rh-Sn and Ir-Sn cluster complexes M3(CO)6(mu-SnPh2)3(SnPh3)3, 1 (M=Rh) and 2 (M=Ir). Both compounds contain triangular M3 clusters with three bridging SnPh2 and three terminal SnPh3 ligands. The M-M bonds are unusually long. Molecular orbital calculations indicate that this is due to the importance of M-Sn bonding and weak direct M-M interactions. Reaction of 1 with Ph3SnH at reflux in 1,2-dichlorobenzene solvent yielded the complex Rh3(CO)3(SnPh3)3(mu-SnPh2)3(mu3-SnPh)2, 3, which contains eight tin ligands: three terminal SnPh3, three edge-bridging SnPh2, and two triply bridging SnPh ligands.

Hexaruthenium carbonyl cluster complexes with basal edge-bridged square pyramidal metallic skeleton: efficient synthesis of 2-imidopyridine derivatives and determination of their reactive sites in carbonyl substitution reactions.

The reactions of [Ru(3)(CO)(12)] with half equivalent of 2-amino-6-methylpyridine (H(2)ampy) or 2-aminopyridine (H(2)apy) in refluxing xylene give the hexanuclear products [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-L)(mu-CO)(2)(CO)(14)] (L = ampy, 1; apy, 2). These reactions represent the first high-yield syntheses of hexanuclear complexes with a basal edge-bridged square pyramidal metallic skeleton. Five metal atoms of these complexes are bridged by the N-donor ligand in such a way that the edge-bridging metal atom is attached to the pyridine nitrogen, while the basal atoms of the square pyramid are capped by an imido fragment that arises from the activation of both N-H bonds of the NH(2) group. The reactive sites of these complexes in CO substitution reactions have been determined by studying the reactivity of 1 with triphenylphosphine. Two kinetically controlled monosubstitutions take place on the edge-bridging metal atom in positions cis to the pyridine nitrogen, leading to a mixture of two isomers of formula [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(13)(PPh(3))] (3 and 4). On heating at 80 degrees C, these monosubstituted isomers are transformed, via a dissociative pathway, into the product of thermodynamic control (5), which has the PPh(3) ligand on the apical Ru atom. The di- and trisubstituted derivatives [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(12)(PPh(3))(2)] (6) and [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(11)(PPh(3))(3)] (7) are stepwise formed from 3-5 and PPh(3). Compound 6 has the PPh(3) ligands on the edge-bridging and apical Ru atoms, and compound 7 has an additional PPh(3) ligand on an unbridged basal Ru atom. The compound [Ru(6)(mu(3)-H)(2)(mu(5)-eta(2)-ampy)(mu-CO)(2)(CO)(12)(mu-dppm)] (8), in which a basal and the apical Ru atoms are spanned by the dppm ligand, has been isolated from the reaction of 1 with bis(diphenylphosphino)methane.

On the Formation of Silver Carbonyl Clusters in CO Droplets

Neutral silver cluster CO compounds have been produced by pick-up of silver atoms by large CO droplets. FTIR spectra in the CO stretching frequency region reveal the presence of both fully covered Ag n clusters for n 45 and silver cluster carbonyl complexes Ag n (CO) m for n ≤ 15. Cationic Ag n (CO) + m 1 ≤ n ≤ 15 and m = 1, 2, 3 were produced by electron impact ionization and identified mass spectrometrically. A post ionization fragmentation mechanism has been proposed to explain the abundance pattern of ionic distributions.

The activation and transformations of acenaphthylene by osmium carbonyl cluster complexes

The reaction of Os 3(CO) 10(NCMe) 2 ( 1) with an excess of acenaphthylene at room temperature provided the complex Os 3(CO) 10(μ-H)(μ–η 2-C 12H 7) ( 2). Compound 2 contains a σ–π coordinated acenaphthyl ligand bridging an edge of the cluster. Compound 2 was converted to the complex Os 3(CO) 9(μ-H) 2(μ 3–η 2-C 12H 6) ( 3) when heated to reflux in a cyclohexane solution. Compound 3 contains a triply bridging acenaphthyne ligand. Compound 3 reacts with acenaphthylene again at 160 °C to yield four new cluster complexes: Os 4(CO) 12(μ 4–η 2:η 2-C 12H 6) ( 4); Os 2(CO) 6(μ–η 4-C 24H 12) ( 5); Os 3(CO) 9(μ-H)(μ 3–η 4-C 24H 13) ( 6); and Os 2(CO) 5(μ–η 4-C 24H 12)(η 2-C 12H 8) ( 7). All compounds were characterized crystallographically. Compound 4 is a butterfly cluster of four osmium atoms bridged by a single acenaphthyne ligand. Compounds 5 and 7 are dinuclear osmium clusters containing metallacycles formed by the coupling of two equivalents of acenaphthyne. Compound 6 is a triosmium cluster formed by the coupling of an acenaphthyne ligand to an acenapthyl group that is coordinated to the cluster through a combination of σ and π-bonding.

Syntheses and structures of selenido dimanganese and iron–manganese carbonyl cluster complexes

The bis-selenido tetramanganese complex, Mn 4(CO) 15(PPh 3) 2(μ 3-Se) 2 ( 1), was obtained from the reaction of Mn 2(CO) 9(NCMe) with SePPh 3. Three new bis-selenido bimetallic iron–manganese complexes, CpFeMn 3(CO) 13(PPh 3)(μ 3-Se) 2 ( 2), Cp 2Fe 2Mn 2(CO) 10(PPh 3)(μ 3-Se) 2 ( 3) and Cp 2Fe 2Mn 2(CO) 11(μ 3-Se) 2 ( 4) were obtained from the reaction of CpFeMn(CO) 7 with SePPh 3 in the presence of trimethylamine N-oxide. Compounds 1, 2 and 3 were characterized by single crystal X-ray diffraction analyses. All three complexes contain an M 4(μ 3-Se) 2 cluster core with a carbonyl bridged MnMn single bond.

Influence of the bridging ligand on the substitution chemistry of neutral and cationic triruthenium carbonyl cluster complexes derived from 1,1-dimethylhydrazine

The reactivity of the neutral triruthenium carbonyl cluster [Ru 3(μ-H)(μ 3-HNNMe 2)(CO) 9] ( 1) and its protonated derivative [Ru 3(μ-H) 2(μ 3-HNNMe 2)(CO) 9][BF 4] ( 2), both containing a face-capping 5-electron donor 1,1-dimethylhydrazido ligand, with triphenylphosphane has been studied. Compound 1 gives a mixture of two non-interconvertible isomeric carbonyl substitution products [Ru 3(μ-H)(μ 3-HNNMe 2)(CO) 8(PPh 3)] which bear the phosphane ligand attached to the same Ru atom as either the NMe 2 ( 3a) or the NH fragments ( 3b). Protonation of the 3a and 3b mixture with [HOEt 2][BF 4] gives a mixture of two non-interconvertible isomeric cationic dihydrido derivatives [Ru 3(μ-H) 2(μ 3-HNNMe 2)(CO) 8(PPh 3)][BF 4] ( 4a and 4b) which maintain the phosphane ligand in the same position as their neutral precursors. Compound 4a can be selectively prepared from complex 2 and triphenylphosphane. Deprotonation of complex 4a with triethylamine gives compound 3a, selectively. These results contrast with those previously known for carbonyl substitution reactions on triruthenium clusters isostructural with compounds 1 and 2 but containing other face-capping five-electron donor ligands. The hardness of the bridging ligand is presented as an important factor in relation to the observed regioselectivity. The X-ray structures of compounds 2 and 4a are reported.

Facile introduction of bridging MPh 2 groups (MGe, Sn, Pb) into platinum–pentaruthenium and hexaruthenium carbido carbonyl cluster complexes

The reactions of PtRu 5(CO) 16(μ 6-C) ( 1) with Ph 3GeH and Ph 3SnH afforded the trimetallic cluster complexes PtRu 5(CO) 15(μ-GePh 2)(μ 6-C) ( 4) and PtRu 5(CO) 15(μ-SnPh 2)(μ 6-C) ( 5), respectively, in good yields. Both the compounds consist of an octahedral cluster of one platinum and five ruthenium atoms with an interstitial carbido ligand in the center. The bridging CO ligand in 1 was replaced by a bridging GePh 2 group in 4 and a bridging SnPh 2 group in 5. The lead homologue PtRu 5(CO) 15(μ-PbPh 2)(μ 6-C) ( 6) was obtained from the reaction of 1 with Pb 2Ph 6. The reaction of PtRu 5(CO) 15(PMe 2Ph)(μ 6-C) ( 2) with Ph 3SnH yielded the phosphine derivative of 5, PtRu 5(CO) 14(μ-SnPh 2)(PMe 2Ph)(μ 6-C) ( 7). Compound 7 was obtained in a higher yield from the reaction of 5 with PMe 2Ph. The reaction of Ru 6(CO) 14(η 6-C 6H 6)(μ 6-C) ( 3) with Ph 3SnH yielded the new hexaruthenium complex Ru 6(CO) 13(μ-SnPh 2)(η 6-C 6H 6)(μ 6-C) ( 8) containing a bridging SnPh 2 ligand. Evidence for benzene formation in the formation of compound 5 indicates the fate of the phenyl group that was cleaved from the tin atom in that reaction.

Efficient Reduction of Sulfur Dioxide with Hydrogen over TiO2-Supported Catalysts Derived from Ruthenium Salts and Ruthenium Cluster Complexes

Catalytic reduction of SO2 to elemental sulfur was carried out over supported ruthenium catalysts that were derived not only from hexaruthenium carbonyl cluster complexes but also from RuCl3 as the precursor. The activity was largely dependent on the kind of metal oxide support used. Compared to the known systems, the TiO2-supported ruthenium catalysts operated with higher efficiency at lower temperature. Moreover, the selectivity was totally to elemental sulfur, forming no detectable amount of unfavorable H2S. H2S-free catalysis appeared to be a common feature of ruthenium catalysts regardless of the kind of precursors. The TiO2-supported catalyst derived from [N(PPh3)2]2[Ru6C(CO)16] was much more active within the 463–508 K temperature region than the catalyst conventionally prepared from RuCl3, while both showed similar activity at more elevated temperatures. The kind of cation in anionic cluster complexes and the presence of an interstitial atom are important factors in generating supported catalysts that operate under mild conditions.

Electrochemical behaviour, IR spectroelectrochemistry and theoretical studies of tetracobalt carbonyl cluster complexes with a facial cyclooctatetraene ligand

The redox properties of some cluster complexes with a facial cyclooctatetraene (cot) ligand were investigated using electrochemical and IR spectroelectrochemical techniques. Reduction of [Co4(CO)3(μ3-CO)3(μ3-C8H8)L2] 1 (L2 = η4-C8H8), 2 (L2 = η4-C6H8), and 3 (L2 = η4-6,6-Ph2C6H4) occurs in CH2Cl2 or THF solution in two consecutive one-electron electrochemically reversible steps. Both one- and two-electron primary reduction products are unstable on a longer timescale; eventually degradation (decapitation) of the tetranuclear clusters takes place, to give the stable anion [Co3(CO)3(μ-CO)3(μ3-C8H8)]−5. The electronic structure of 1, 2, the octacarbonyl derivative [Co4(CO)5(μ3-CO)3(μ3-C8H8)] 4, their monoanions, dianions and 5 was investigated using ab initio DFT MO calculations. The calculations showed the monoanions to be relatively stable compared to the neutral parent clusters, the relative stability depending on the type of apical ligand and reflecting its bonding capabilities, namely the possibility of ring slippage for a cot ring. Hence, an η4 → η2 haptotropic shift of the apical C8H8 ring is calculated to occur during the reduction of 1 to give the dianion [1]2−. In marked contrast, in complex 4 the haptotropic shift involves the facial, η8-coordinated cot, which is pushed into an η6-coordination in the optimized structure of the two-electron reduction product [4]2−. In all the cases studied, the second reduction step is however not favored energetically and reinforces the structural and electronic effects caused by the first reduction. The observed decapitation of the anionic tetranuclear cluster complexes can be traced to an ubiquitous weakening of the Coapical–Cobasal bonds.

ChemInform Abstract: The Coordination and Transformation of Arene Rings by Transition Metal Carbonyl Cluster Complexes

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The coordination and transformation of arene rings by transition metal carbonyl cluster complexes

A survey of the synthetic pathways and of the reactivity and catalytic activity of transition metal carbonyl clusters substituted with benzyne (and, for comparison, benzene and diene) ligands is given. Cluster-surface analogies are helpful in gaining an understanding of the homogeneous and heterogeneous catalytic behaviour of the clusters.

Mixed Ruthenium-Iridium Carbonyl Cluster Complexes. Synthesis of the Anions [Ru3Ir2(CO)14]2- and [Ru3Ir2(CO)14H]- and Crystal Structures of Their [tetraphenylphosphonium]+ Salts

The reaction of Ru3(CO)12 and [Ir(CO)4]- (as [PPh4]+ or [N(PPh3)2]+ salts) yields the anion [Ru3Ir2(CO)14]2- (1) which has been found to derive from the intermediate [Ru3Ir(CO)13]- anion. Treatment of (1) with acids gives the conjugated hydrido species [Ru3Ir2(CO)14H]- (2). The two anions were characterized by single-crystal X-ray diffraction of their [PPh4]+ salts. [PPh4]2[Ru3Ir2(CO)14]: space group C2/c, Z=4, a=22.121(5) A, b=10.546(5) A, c=25.931(5) A, β=103.870(5)°, R=0.052 and Rw=0.130 for 3128 independent reflections with I>2σ(I ). [PPh4][Ru3Ir2(CO)14H]: space group P21/c, Z=8, a=22.833(5) A, b=13.893(5) A, c=25.810(5) A, β=92.650(5)°, R=0.070 and Rw=0.150 for 12141 independent reflections with I>2σ(I). Both anions 1 and 2 have a trigonal bipyramidal metal frame. There are two independent anions in the asymmetric unit of 2 differing in their ligand stereochemistry.

The ring opening of 2-vinylthietane by a triosmium carbonyl cluster complex

The reaction of Os3(CO)11(NCMe) with 2-vinylthietane 2 at 25°C yielded two products: Os2(CO)6(η4-μ-SCH2CH2CHCHCH2) 3 (18% yield) and Os3(CO)10[η2-μ-OC(CH2CHCHCH2CH2S)] 4 (36% yield). Compound 4 was characterized by single crystal X-ray diffraction analysis. It contains a triangular triosmium cluster with ten linear terminal carbonyl ligands and a 3-hexeneoylthiolate ligand that bridges an open edge of the cluster through both the sulfur atom and the ketonyl group terminii. Compound 3 has only two osmium atoms, six carbonyl ligands and a bridging pentenylthiolate ligand. The ring opening of vinylthietane by a triosmium cluster occurs exclusively at the vinyl-substituted carbon atom.

Acetylide derivatives of transition metal cluster carbonyls

Modes of formation, structural features, reactivities, and stereochemical nonrigidity of cluster carbonyl complexes with acetylide ligands are considered.

Iridium carbonyl cluster complexes with bidentate phosphine ligands; the X-ray crystal structure of [Ir4(CO)8(dppa)2]·3(THF)

Reactions of [Ir4(CO)12] with 1,1-bis(diphenylphosphino)ethene, Ph2PC(CH2)PPh2 (dppen) and 1,1-bis(diphenylphosphino)amine, Ph2PN(H)PPh2(dppa) gave [Ir4(CO)12−n(L)n−2)] (L=dppen or dppa and n=2 or 4) depending upon the reaction conditions. The structures of the cluster complexes are discussed on the basis of IR, 31P-NMR spectroscopic data and FAB mass spectra. The structure of the disubstituted species [Ir4(CO)8(dppa)2]·3(THF) (THF=tetrahydrofuran, C4H8O) has been determined by X-ray crystallography.