Octahedral iridium carbonyl clusters. Synthesis, characterization and solid state structure of the nitrosyl cluster [Ir 6(CO) 11(μ-CO) 3NO] −

Abstract

The nitrosylcarbonyl cluster [Ir 6(CO) 14NO] − has been prepared by one-electron oxidation of [Ir 6(CO) 15] 2−, followed by addition of NO at low temperature. The structure of the salt [NMe 3(CH 2Ph)][Ir 6(CO) 11( μ-CO) 3NO] was solved by direct methods and difference Fourier techniques and refined down to R = 0.036, for 3239 observed reflections having I > 3 σ( I). The cluster of idealized C s point group symmetry contains an octahedral metal framework of iridium atoms, an NO group linearly bound, which acts as a three-electron donor, 11 terminal and three edge-bridging carbonyl ligands. The IrN separation of 1.75(3) Å is the shortest metal-to-ligand bond distance. Average distances are: IrIr = 2.773 A ̊ , Ir C term = 1.86 A ̊ , C term −O term = 1.16 A ̊ , Ir C bridg = 2.02 A ̊ , C bridg − O bridg = 1.19 A ̊ .