Hexaruthenium and octaruthenium carbonyl cluster complexes derived from 2-amino-6-methylpyridine — Novel coordination modes for 2-imidopyridines

Abstract

The hexanuclear ruthenium cluster [Ru6(µ3-H)2(µ-H)2(µ4-κ2-ampy)2(CO)14] (1) and the octanuclear one [Ru8(µ-H)(µ4-κ2-ampy)3(µ3-κ2-Hampy)(µ-CO)2(CO)15] (2) have been prepared by treating [Ru6(µ3-H)2(µ5-κ2-ampy)(µ-CO)2(CO)14] with 2-amino-6-methylpyridine (H2ampy) in decane at reflux temperature. Their metal atoms are supported by ligands that derive from the activation of one (complex 2) or both N—H bonds (complexes 1 and 2) of the H2ampy amino fragment. Both contain at least one ampy ligand featuring an unprecedented coordination type: the imido N atom caps a triangle of metal atoms while the pyridine nitrogen is attached to an additional metal atom. One of the ampy ligands of cluster 2 also displays another unprecedented coordination type: it caps a distorted square of metal atoms through the imido N atom while the pyridine nitrogen is attached to one of the atoms included in that square.Key words: ruthenium, cluster compounds, amido ligands, imido ligands.