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

The hexanuclear ruthenium cluster [Ru-6(mu(3)-H)(2)(mu-H)(2)(mu(4)-kappa(2)-ampy)(2)(CO)(14)] (1) and the octanuclear one [Ru-8(mu-H)(mu(4)-kappa(2)-ampy)(3)(mu(3)-kappa(2)-Hampy)(mu-CO)(2)(CO)(15)] (2) have been prepared by treating [Ru-6(mu(3)-H)(2)(mu(5)-kappa(2)-ampy)(mu-CO)(2)(CO)(14)] with 2-amino-6-methylpyridine (H(2)ampy) 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 H(2)ampy 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.