Thermolysis of [Ru3(CO)12] in cyclohexene for 24 h affords the complexes [Ru(CO)3(η4-C6H8)] (1), [Ru3H2(CO)9(μ2-η1:η2:η1-C6H8)] (2), [Ru4(CO)12(μ4-C6H8)] (3) [Ru4(CO)9(μ4-C6H8)(η6-C6H6)] (4a and 4b, two isomers) and [Ru5(CO)12(μ4-η2-C6H8)(η4-C6H8)] (5), where 1, 3, 4a and 4b have been previously characterised as products of the thermolysis of [Ru3(CO)12] with cyclohexa-1,3-diene. The molecular structures of the new clusters 2 and 5 were determined by single-crystal X-ray crystallography, showing that two conformational polymorphs of 5 exist in the solid state, differing in the orientation of the cyclohexa-1,3-diene ligand on a ruthenium vertex.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The ionic coupling reaction of the dianion [Os3(CO)9(R2C2)]2− (R=Me, Ph) with two equivalents of the monocation [Ru(η5-C5H5)(CH3CN)3]+ affords the neutral clusters [Os3Ru2(CO)9(R2C2)(η5-C5H5)2] [R=Me, 1 and R=Ph, 2] in ca. 80% yield. An X-ray crystallographic study of 1 confirms that these clusters exhibit a capped pseudo-octahedral Os3Ru2C2 core, with the alkyne bonded parallel to the hinge bond of the capped butterfly metal geometry in a μ4–η2 manner, the Ru atoms adopting the wing-tip and capping positions. Reaction of the activated cluster [Os3RuH(η5-C5H5)(CO)10(MeCN)] (3) with RCCR (R=Me, Ph) affords the related clusters [Os3RuH(CO)9(η5-C5H5)(R2C2)] (R=Me, 4 and R=Ph, 5) in ca. 35% yield. The reaction with PhCCPh also produces [Os3Ru(CO)8(η5-C5H5)(PhCCPh)(PhCC(H)Ph)] (6) in ca. 15% yield. An X-ray crystallographic study shows that this cluster has a pseudo-octahedral Os3RuC2 core, with the Ru(η5-C5H5) unit adopting the wing-tip position, the alkyne bonded in a μ4–η2 arrangement and the ethenyl ligand bridging an Os–Os edge in a μ2–η1:η2 configuration.

Thermolysis of [Ru3(CO)12] in cyclohexene for 24 h affords the complexes [Ru(CO)3(g -C6H8)] (1), [Ru3H2(CO)9(l2-g :g:g-C6H8)] (2), [Ru4(CO)12(l4C6H8)] (3) [Ru4(CO)9(l4-C6H8)(g -C6H6)] (4a and 4b, two isomers) and [Ru5(CO)12(l4-g -C6H8)(g -C6H8)] (5), where 1, 3, 4a and 4b have been previously characterised as products of the thermolysis of [Ru3(CO)12] with cyclohexa-1,3-diene. The molecular structures of the new clusters 2 and 5 were determined by single-crystal X-ray crystallography, showing that two conformational polymorphs of 5 exist in the solid state, differing in the orientation of the cyclohexa-1,3-diene ligand on a ruthenium vertex.

The reaction of [Os4(CO)9(RCCR)(η6-C6H6)] (R=Me, Ph) with Me3NO in the presence of 1,3-cyclohexadiene or 1,4-cyclohexadiene yields the clusters [{Os4(CO)8(RCCR)(η6-C6H6)}2(μ2-η2:η2-C6H8-1,3)] and [{Os4(CO)8(RCCR)(η6-C6H6)}2(μ2-η2:η2-C6H8-1,4)], respectively. The molecular structure of [{Os4(CO)8(MeCCMe)(η6-C6H6)}2(μ2-η2:η2-C6H8-1,3)] has been determined by single crystal X-ray diffraction, and represents the first example of two osmium cluster fragments linked by 1,3-cyclohexadiene through a μ2-η2:η2-bridge.

The reaction of the monoanion [Os3H(CO)11]– 1 with 1 equivalent of the cation [Ru(C5H5)(MeCN)3]+ 2, in CH2Cl2, formed the mixed-metal, tetranuclear cluster [Os3RuH(CO)11(η5-C5H5)] 3 in high yield. Subsequent deprotonation of 3 with 1,8-diazabicyclo[5.4.0]undec-7-ene, in CH2Cl2, afforded the anion [Os3Ru(CO)11(η5-C5H5)]– 4, and reaction of 4 with a second equivalent of [Ru(C5H5)(MeCN)3]+ provided the new bis-(cyclopentadienyl) cluster [Os3Ru2(CO)9(µ3-CO)2(η5-C5H5)2] 5 in ca. 80% yield. Alternatively, reduction of [Os3(CO)12] with K/Ph2CO afforded the known cluster dianion [Os3(CO)11]2– 6 which can be treated with 2 equivalents of [Ru(C5H5)(MeCN)3]+ to produce 5 in 75% yield. The clusters 3 and 5 have been fully characterised by both spectroscopic and crystallographic methods. The structure of 3 contains an Os3Ru tetrahedron in which the cyclopentadienyl ligand is co-ordinated to the Ru atom in an η5 terminal mode. The metal framework in 5 is a trigonal bipyramid, but may be viewed as an Os3Ru tetrahedral unit, as in 3, to which a second Ru atom capping an Os2Ru triangular face has been added. Both the cyclopentadienyl ligands remain in η5 terminal bonding sites co-ordinated to the two Ru atoms.

The reaction of the dianion [Ru5C(CO)(14)](2-) with 2 equivalents of [Ru(eta(5)-C5H5)(MeCN)(3)](+) afforded two new clusters, the hexanuclear anion [Ru6C(CO)(14)(eta(5)-C5H5)](-) 1 and the neutral heptanuclear cluster [Ru7C(CO)(14)-(eta(5)-C5H5)(2)] 2 in high yields. In a similar reaction the hexanuclear dianion [Ru6C(CO)(16)](2-) may be 'capped' by [Ru(eta(5)-(CH5)-H-5)(MeCN)(3)](+) to afford good yields of both the heptanuclear monoanion [Ru7C(CO)(16)(eta(5)-C5H5)](-) 3 and the neutral cluster 2. The clusters 1, 2 and 3 have been fully characterised by both spectroscopic and crystallographic methods. The crystal structures show that the metal framework of all three clusters is based on a central Ru6C octahedral core. In 1 one of the core atoms is co-ordinated to an eta(5)-C5H5 ligand, while in 2 an additional Ru(eta(5)-C5H5) group caps one triangular face of the octahedron to give a capped octahedral framework. In 3 the single eta(5)-C5H5 ligand is co-ordinated to the capping Ru atom in the capped octahedral framework.

Ionic coupling of the mononuclear cation [Ru(η5-C5H5)(MeCN)3]+ with the cluster dianion [Os5(CO)15]2– afforded the neutral heptanuclear cluster [Os5Ru2(CO)15(η5-C5H5)2] which has been shown by X-ray diffraction studies to contain a tricapped tetrahedral metal core.

Reduction of the heptaosmium cluster [Os7(CO)21] With [Et4N][NH4) gives the cluster dianion [Os7(CO)20]2−,1, in high yield. The reaction of the dianion with [AuPR3Cl] (R=Et or Ph) in the presence of TlPF6 forms [Os7((CO)20(AuPR3)2] [R=Et (2a);R = Ph(2b)] in 80% yield, while the corresponding reaction with (Os(C6H6)(CH3CN)3]2+ gives [Os8(CO)20 (η6-C6H6)] (3) in reasonable yield (ca. 30%). The dianion,1, and the clusters2 and3 have been fully characterized by bout spectroscopic and crystallographic methods. The crystal structure of the [Ph4P]+ salt of1 shows that the metals in the anion adopt a capped octahedral geometry, with all twenty carbonyl ligands in terminal sites. The metal core geometry in2a is best described as a tricapped octahedron, and is based on the structure of the dianion1 with two adjacent octahedral faces capped by the Au atoms of the two AuPEt3 groups. In a similar fashion, the geometry of3 is related to that of1 with the addition of an Os(C6H6) unit capped to a triangular face, to give a bicapped octahedral framework.

Reactions of the cluster dianion [Os5(CO)15]2– with [Os(η6-C6H6)(MeCN)3]2+ and [Os(C6H5Me)(CF3SO3)2] provided [Os6(CO)15(η6-C6H6)]1 and [Os6(CO)15(η6-C6H5Me)]2, respectively, in good yield (≈45%). Reduction of the hexaosmium cluster [Os6(CO)18] with K–Ph2CO gave the cluster dianion [Os6(CO)17]2–3 in quantitative yield. When this dianion was treated with [Os(η6-C6H6)(MeCN)3]2+ the heptanuclear cluster [Os7(CO)17(η6-C6H6)]4 was obtained in fair yield, while the corresponding reaction with [Os(η6-C6H5Me)(CF3SO3)2] gave [Os7(CO)17(η6-C6H5Me)]5 in similar yield (ca. 25%). The four arene clusters have been characterised by spectroscopic techniques, and the molecular geometries of 1, 2 and 4 established by single-crystal X-ray diffraction techniques. In both 1 and 2 the metal framework geometry is best described as a bicapped tetrahedron. In 1 the η6-C6H6 ligand occupies a site on the central Os4 tetrahedron while in 2 in the η6-arene is co-ordinated to one of the capping Os atoms. The metal framework in 4 may be viewed as derived from a bicapped tetrahedron with the seventh metal capping one of the caps to give a chain of four fused tetrahedra. The η6-C6H6 ligand in 4 occupies a similar site to that found in 1.

Reaction of the alkyne-substituted cluster anion [Os3(CO)9(R1CCR2)]2− with the cation [Os(η6-C6H6)(CH3CN)]2+ affords the neutral tetranuclear cluster Os4(CO)9(η6-C6H6)(R1CCR2) (R1=R2=Me (1a); R1=Me, R2=Ph (1b); R1=R2=Ph (1c)). The structure of 1a has been confirmed by a single-crystal X-ray analysis. The metals adopt a ‘butterfly’ geometry with the alkylenic CC vector parallel to the ‘hinge’ vector of the ‘butterfly’, and the η6-C6H6 ligand occupies a terminal site on one of the ‘wingtip’ Os atoms. Complexes 1a and 1b may also be prepared by the reaction of the activated arene cluster Os4H2(CO)9(η6-C6H6)(CH3CN) with MeCCMe and MeCCPh, respectively. Under similar reaction conditions, with PhCCPh, the arene and acetonitrile ligands are substituted by the alkyne to give the known complex Os4H2(CO)9(PhCCPh)2 (2c).