Synthesis, structure, and reactivity of some new dipyridyl and diamine-bridged dinuclear oxomolybdenum(VI) complexes

Some new diimine and diamine-bridged dinuclear Mo(VI) complexes of the general formula [(MoO2L)(2)(mu-N-N)] [(mu-N-N) = 4,4-bipyridine (4,4'-bpy) (2); trans-1,2-bis(4-pyridyl) ethene (bpe) (3); trans-1,2-bis(4-pyridyl) ethane (bpa) (4) and p-phenylenediamine (ppda) (5)] along with their common mononuclear precursor [MoO2L(C2H5OH)] (1) have been synthesized, using 2-hydroxy benzoylhydrazone of 2-hydroxybenzaldehyde as tridentate ONO donor Ligand (LH2), and structurally characterized. Structures of all the three dinuclear complexes 2, 3 and 5 are centrosymmetric with both the Mo(VI) acceptor centers existing in the same coordination environment. One 2 from the four dinuclear complexes has taken part in oxo-transfer to the substrate PPh3 forming the corresponding dinuclear Mo(IV)-Mo(IV) complex [(MoOL)(2)(mu-N-N)] (2a). (c) 2006 Elsevier Ltd. All rights reserved.