Reaction of [Os3(CO)10(MeCN)2] with 2,3-bis(2-pyridyl)pyrazine and pyrazyne.: Synthesis, characterization and electrochemical behavior of 1:1 and 1:2 ligand:cluster complexes

The diimine-bridged, bis-triosmium carbonyl complexes [{Os-3(CO)(10)(mu-H)}(2)(pyz)] 1b, [{Os-3(CO)(10)}(2)(dpp)] 2b, (pyz = pyrazine; dpp = 2,3-bis(2-pyridyl)pyrazine) and their corresponding 1:1 ligand:cluster complexes [Os-3(CO)(10)(mu-H)(pyz)], 1a, [Os-3(CO)(10)(dpp)], 2a, were synthesized by the reaction of [Os-3(CO)(10)(MeCN)(2)] with pyz and dpp ligands. All compounds were characterized by IR,H-1-NMR spectroscopy and elemental analysis. Electrochemistry was used to examine the redox properties of 1-2 and of complexes [Os-3(CO)(10)(mu-H)(py)], 3, for comparison purposes. The electrochemical behavior of the bridged bis-triosmium species 1b-2b provided strong evidence for the electronic interaction between the two metal centers. (C) 1998 Elsevier Science S.A. All rights reserved.