High-Nuclearity Ruthenium Carbonyl Cluster Complexes Derived from 2-Amino-6-methylpyridine: Synthesis of Nonanuclear Derivatives Containing μ4- and μ5-Oxo Ligands
datasetposted on 24.07.2006, 00:00 by Javier A. Cabeza, Ignacio del Río, Pablo García-Álvarez, Daniel Miguel
Nonanuclear cluster complexes [Ru9(μ3-H)2(μ-H)(μ5-O)(μ4-ampy)(μ3-Hampy)(CO)21] (4) (H2ampy = 2-amino-6-methylpyridine), [Ru9(μ5-O)2(μ4-ampy)(μ3-Hampy)2(μ-CO)(CO)20] (5), [Ru9(μ5-O)2(μ4-ampy)(μ3-Hampy)2(μ-CO)2(CO)19] (6), and [Ru9(μ4-O)(μ5-O)(μ4-ampy)(μ3-Hampy)(μ-Hampy)(μ-CO)(CO)19] (7), together with the known hexanuclear [Ru6(μ3-H)2(μ5-ampy)(μ-CO)2(CO)14] (2) and the novel pentanuclear [Ru5(μ4-ampy)2(μ-CO)(CO)12] (3) complexes, are products of the thermolysis of [Ru3(μ-H)(μ3-Hampy)(CO)9] (1) in decane at 150 °C. Two different and very unusual quadruply bridging coordination modes have been observed for the ampy ligand. Compounds 4−7 also feature one (4) or two (5−7) bridging oxo ligands. With the exception of one of the oxo ligands of 7, which is in a distorted tetrahedral environment, the remaining oxo ligands of 4−7 are surrounded by five metal atoms. In carbonyl metal clusters, quadruply bridging oxo ligands are very unusual, whereas quintuply bridging oxo ligands are unprecedented. By using 18O-labeled water, we have unambiguously established that these oxo ligands arise from water.