1,1,2,2,2,3,3,3-Octacarbonyl-1,1,2,3-tetrakis(1,3,5-triaza-7-phosphatricyclo[3.3.1.1^3,7]decane-κP)-triangulo-triosmium(0)

The title compound, [Os3(C6H12N3P)4(CO)8], crystallizes in the orthorhombic space group Pbca with Z = 8. The molecule consists of a triangular triosmium(0) core surrounded by eight carbonyl ligands and four 1,3,5-triaza-7-phosphatricyclo[3.3.1.13,7]decane (or PTA) ligands. One Os atom is coordinated by two PTA ligands and two CO ligands, while the other two Os atoms are each bonded to a single PTA ligand and three CO ligands. There is a small disorder associated with the Os3 unit so that a minor orientation has an occupancy of 2.17 (4)%. The title compound represents the first structurally characterized triangular Os3 carbonyl cluster with four monodentate tertiary phosphane ligands.