Synthesis of monoamine derivatives of [Ir4(CO)12].: X-ray crystal structure of [Ir4(CO)11(4-picoline)]

The mono-substituted amine derivatives [Ir-4(CO)(11)L] (L = pyridine (1), 4-methylpyridine (2), 4-ter-butyl pyridine (3), 3,5-dimethylpyridine (4), 3,4-dimethylpyridine (5)) were obtained by the reaction of [Ir-4(CO)(11)Br](-) with the corresponding aromatic amine. In the solid state, cluster 2 has an approximate C-S symmetry with all terminal ligands as shown by an X-ray analysis. In solution, this unbridged structure is in dynamic equilibrium with two other isomeric forms having three edge-bridging CO's on a common basal face and the amine ligand coordinated in axial or in radial position relative to this face. (c) 2005 Elsevier B.V. All rights reserved.