Trinuclear and Tetranuclear Ruthenium Carbonyl Nitrosyls: Oxidation of a Carbonyl Ligand by an Adjacent Nitrosyl Ligand.

Trinuclear and tetranuclear ruthenium carbonyls of the types Ru 3 (CO) n (NO) 2 , Ru 3 (N)(CO) n (NO), Ru 3 (N) 2 (CO) n , Ru 3 (N)(CO) n (NCO), Ru 3 (CO) n (NCO)(NO), Ru 4 (N)(CO) n (NO), Ru 4 (N)(CO) n (NCO), and Ru 4 (N) 2 (CO) n related to species observed experimentally in the chemistry of Ru 3 (CO) 10 (µ-NO) 2 have been investigated using density functional theory. In all cases, the experimentally observed structures have been found to be low-energy structures. The low-energy trinuclear structures typically have a central strongly bent Ru-Ru-Ru chain with terminal CO groups and bridging nitrosyl, isocyanate, and/or nitride ligands across the end of the chain. The low-energy tetranuclear structures typically have a central Ru 4 N unit with terminal CO groups and a non-bonded pair of ruthenium atoms bridged by a nitrosyl or isocyanate group.