Mixed-valence state of a series of sulfur-bridged triangular trinuclear molybdenum and tungsten clusters [MonW3-nS4(Hnta)(3)](3-) (n=0-3)

The mixed-valence state of IV, IV, III of a series of triangular clusters h aving the general formula [M3S4(Hnta)(3)](3-), where M = MO3, Mo2W, MoW2 an d W-3, and H(3)nta = nitrilotriacetic acid, was electrochemically generated and characterized by vis-near-IR and ESR spectroscopy. The mixed-valence c lusters exhibited the characteristic intervalence band in the near-IR regio n. Hush analysis revealed that all the mixed-valence clusters are assigned to class II and that the order of degree of delocalization is [W-3](3-) > [ Mo2W](3-), [Mo-3](3-) > [MoW2](3-). (C) 1999 Elsevier Science S.A. All righ ts reserved.