Triruthenium, Hexaruthenium, and Triosmium Carbonyl Derivatives of 2-Amino-6-phenylpyridine

The triruthenium cluster complexes [Ru 3 (μ-H)(μ 3 -η 2 -HapyPh- N, N )(CO) 9 ] ( 1 ) and [Ru 3 (μ-Η) 2 (μ 3 -η 3 -HapyC 6 H 4 - N, N, C ) 2 (CO) 6 ] ( 2 ) and the hexaruthenium ones [Ru 6 (μ 3 -H) 2 (μ 5 -η 2 -apyPh- N, N )(μ-CO) 2 (CO) 14 ] ( 3 ) and [Ru 6 (μ 3 -H)(μ 5 -η 3 -apyC 6 H 4 - N, N, C )(μ-CO) 3 (CO) 13 ] ( 4 ) have been prepared from [Ru 3 (CO) 12 ] and 2-amino-6-phenylpyridine (H 2 apyPh). Compound 1 contains a deprotonated HapyPh ligand capping a face of the metal triangle. Compound 2 contains two cyclometalated HapyC 6 H 4 ligands, each spanning a Ru−Ru edge through the N atom of the amido fragment and chelating the remaining Ru atom through both the pyridine N atom and the C atom of the cyclometalated ring. The hexanuclear derivatives 3 and 4 have an uncommon basal edge-bridged square pyramidal metallic skeleton. The bridging ligand of 3 is a doubly deprotonated apyPh ligand which caps the metallic square through the exocyclic N atom, while is attached to the Ru atom that bridges the edge of the square pyramid through the pyridine N atom. Complex 4 is structurally related to 3 but has a cyclometalated phenyl ring. It has been established that compound 2 is formed by reaction of 1 with H 2 apyPh and that complex 3 is formed by reaction of 1 with [Ru 3 (CO) 12 ]. While the hydrogenation of 4 gives 3, the thermolysis of 3 gives 4 among other unidentified products. The reaction of the osmium cluster [Os 3 (CO) 10 (MeCN) 2 ] with H 2 apyPh gives a 1:5 mixture of the edge-bridged decacarbonyl derivatives [Os 3 (μ-Η)(μ-η 1 -HapyPh- N )(CO) 10 ] ( 5 ) and [Os 3 (μ-H)(μ-η 2 -HapyPh- N, N )(CO) 10 ] ( 6 ). Both compounds give the face-capped nonacarbonyl derivative [Os 3 (μ-H)(μ 3 -η 2 -HapyPh- N, N )(CO) 9 ] ( 7 ) upon irradiation with UV light. Curiously, while complexes 5 and 7 are stable in refluxing toluene, the thermolysis of 6 gives a mixture of 5, 7, and the cyclometalated dihydride [Os 3 (μ-H) 2 (μ-η 3 -HapyC 6 H 4 - N, N, C )(CO) 9 ] ( 8 ).