Manganese nitride complexes in oxidation states III, IV, and V: synthesis and electronic structure.

The synthesis and characterization of a series of manganese nitrides in a tripodal chelating tris(carbene) ligand framework is described. Photolysis of [(TIMEN(xyl))Mn(N(3))](+) (where TIMEN(xyl) = tris[2-(3-xylylimidazol-2-ylidene)ethyl]amine) yields the isolable molecular Mn(IV) nitride, [(TIMEN(xyl))Mn(N)](+). Spectroscopic and DFT studies indicate that this Mn(IV) d(3) complex has a doublet electronic ground state. The metal-centered one-electron oxidation of this Mn(IV) species results in formation of the pentavalent Mn(V) nitride, [(TIMEN(xyl))Mn(N)](2+). Unlike previously reported, tetragonal Mn(V) nitrides with a d(2), nonmagnetic S = 0 ground state, this trigonal bipyramidal complex has a triplet ground state S = 1. One-electron reduction of [(TIMEN(xyl))Mn(N)](+) produces the neutral, nonmagnetic trivalent [(TIMEN(xyl))Mn(N)] species with a d(4) low-spin, S = 0, ground state.