The heating of the 18-electron complex [3,3-(dppb)-3-H-3-Cl-closo-3,1,2-RuC2B9H11] (3) in benzene at 80 °C in the presence of a small amount of CCl4 as initiator afforded paramagnetic 17-electron s...

Carborane complexes of ruthenium(III): studies on thermal reaction chemistry and the catalyst design for atom transfer radical polymerization of methyl methacrylate.

Large-cage (11–13-vertex) dicarbon metallacarboranes of platinum metals with mono- and polycyclic diolefin ligands

Mononuclear closo-ruthenacarborane complexes containing a rare eight-membered metal-diphosphine ring

The determination of the molecular structures of metallacarboranes by X-ray diffraction remains critical to the development of the field, in some cases being the only viable way in which the overall architecture and the isomeric form of the molecule can be established. In such studies one problem frequently met is how to distinguish correctly {BH} and {CH} vertices, and this review begins by describing two relatively new methods, the Vertex-Centroid Distance (VCD) and Boron-Hydrogen Distance (BHD) methods, that have been developed to overcome the problem. Once the cage C atoms are located correctly, the resulting metallacarborane structure can frequently be analysed on the basis that cage B has a greater Structural Trans Effect (STE) than does cage C. In the absence of significant competing effects this gives rise to unequal M–L distances for a homogeneous ligand set and to a preferred Exopolyhedral Ligand Orientation (ELO) for a heterogeneous ligand set. ELO considerations can be used, amongst other things, to rank order the STEs of ligands and to identify suspect (in terms of cage C atom positions) metallacarborane structures.

What Can We Learn from the Crystal Structures of Metallacarboranes

Metallacarboranes (carboranes incorporating one or more metal atoms in the cage framework, alternatively described as metal-carborane complexes), comprise a huge family of compounds of which thousands have been prepared and characterized. This chapter presents a detailed summary of this area in its many facets, including methods of synthesis, molecular and electronic structures, physical properties, and reactivity. An overview of general synthetic approaches is followed by a review of the preparation, structures, and properties of the smaller (6- and 7-vertex) metallacarboranes, intermediate-sized 8-11 vertex clusters, the 12-vertex icosahedral systems, and finally the supraicosahedral (13- to 15-vertex) cages.

Metallacarboranes of the transition and lanthanide elements

A facile preparative procedure was developed for the synthesis of 17-and 18-electron closo-(diphosphine)ruthenacarborane complexes. This method is based on the replacement of PPh3 ligands with bis(diphenylphosphino)alkanes Ph2P(CH2)nPPh2 (n = 2—4) in ruthenacarborane 3,3-(PPh3)2-3-Cl-3-H-closo-3,1,2-RuC2B9H11. The resulting complexes exhibit high activity in controlled radical polymerization of vinyl monomers.

Facile method for the synthesis of ruthenacarboranes, diamagnetic 3,3 -[Ph2P (CH2)nPPh2]-3-H-3-Cl-closo-3,1,2-RuC2B9H11 (n = 3 or 4) and paramagnetic 3,3 -[Ph2P (CH2)nPPh2] -3 -Cl -closo -3,1,2 -RuC2B9H11 (n = 2 or 3), as efficient initiators of controlled radical polymerization of vinyl monomers

A. S. Nikiforov

Papers

Facile method for the synthesis of ruthenacarboranes, diamagnetic 3,3 -[Ph2P (CH2)nPPh2]-3-H-3-Cl-closo-3,1,2-RuC2B9H11 (n = 3 or 4) and paramagnetic 3,3 -[Ph2P (CH2)nPPh2] -3 -Cl -closo -3,1,2 -RuC2B9H11 (n = 2 or 3), as efficient initiators of controlled radical polymerization of vinyl monomers