Cluster Syntheses. 2. The Role of Heteroatoms in the Formation of High Nuclearity Transition-Metal Carbonyl Cluster Compounds. The Condensation of Small Clusters

Article abstract of DOI:10.1021/ja00342a031

The compounds HOs₃(μ3-S)(μ-HC=NR)(CO)9, Ia, R= C6H5, and Ia', R= C6H4-p-F, lose CO and/or H2 when heated to form the hexanuclear osmium complexes Os6(μ4-S)(μ-HC=NR)2(CO)18, IIa, R=C6H5, and IIa', R= C6H4-p-F.H2Os6(μ4-S)(μ3-S)(μ-HC=NR)2(CO)17, IIIa,b, R= C6H5, and IIIa',b', R = C6H4-p-F, which exist as two isomers, H2Os6(μ4-S)(μ3-S)(μ-HC=NR)2(CO)16, IVa-c, R=C6H5, and IVa'-c', R=C6H4-p-F, which exist as three isomers, and Os6(μ4-S)2(μ-HC=NR)2(CO)15, Va, R=C6H5, and Va', R=C6H4-p-F.All compounds have been analyzed by IR and 1H NMR spectroscopy.Compounds IIIa', IVa, and Va have also been characterized by single-crystal X-ray diffraction analyses.Compounds III can be converted to IV, and IV into V.III, IV, and V are believed to be part of a sequence of cluster growth processes in which the sulfido ligands mediate the initial linking of the clusters and the subsequent formation of metal-metal bonds between them.IIIa' contains two open triangular groups of three metal atoms linked by a tetrahedrally coordinated sulfido ligand.In IVa the six metal atoms are arranged in groups of four or two, with the two groups linked by a tetrahedrally coordinated sulfido ligand.In Va the six metal atoms have condensed into a central cluster of four which has the form of a butterfly tetrahedron with sulfido ligands bridging the two open triangular faces.The two remaining metal atoms are bonded to the hinge metal atoms of the central cluster, one to each.