Mixed-valence state of a series of sulfur-bridged triangular trinuclear molybdenum and tungsten clusters [Mo nW 3− nS 4(Hnta) 3] 3− ( n=0–3)

Abstract

The mixed-valence state of IV,IV,III of a series of triangular clusters having the general formula [M 3S 4(Hnta) 3] 3−, where M=Mo 3, Mo 2W, MoW 2 and W 3, and H 3nta=nitrilotriacetic acid, was electrochemically generated and characterized by vis–near-IR and ESR spectroscopy. The mixed-valence clusters exhibited the characteristic intervalence band in the near-IR region. 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−>[Mo 2W] 3−, [Mo 3] 3−>[MoW 2] 3−.