Triruthenium, hexaruthenium, and triosmium carbonyl derivatives of 2-amino-6-phenylpyridine

The triruthenium cluster complexes [Ru-3(mu-H)(mu(3)-eta(2)-HapyPh-N,N)(CO)(9)] (1) and [Ru-3(mu-H)(2)(mu(3)-eta(3)-HapyC(6)H(4)-N,N,C)(2)(CO)(6)] (2) and the hexaruthenium ones [RU6(mu(3)-H)(2)(mu(5)-H)(2)-(mu(5-)eta(2-)apyPh-N,N)(mu-CO)(2)(CO)(14)] (3) and [RU6(mu(3)-H)(mu(5)-eta(3)-apyC(6)H(4)-N,N,C)(mu-CO)(3)(CO)(13)] (4) have been prepared from [RU3(CO)121 and 2-amino-6-phenylpyridine (1-12apyPh). 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 [OS3(mu-H)(mu-eta(1)-HapyPh-N)(CO)(10)] (5) and [OS3(mu-H)(mu-eta(2)-HapyPh-N,N)(CO)(10)] (6). Both compounds give the face-capped nonacarbonyl derivative [Os-3(mu-H)-(mu(3)-eta(2) -HapyPh-NN)(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(mu-H)(2)(mu-eta(3)-HaPYC(6)H(4)-N,N,C)(CO)(9)] (8).