Quadridentate Bridging EO42-(E = S, Mo, W) Ligands and Their Role as Electronic Bridges

Abstract
Three compounds containing two quadruply bonded Mo2(DAniF)3 (DAniF = N,N‘-di-p-anisylformamidinate) units linked by tetrahedral EO42- anions (E = S, Mo, W) have been prepared and characterized by crystallography and NMR. The linkers in these [Mo2(DAniF)3]2(μ-EO4) compounds hold the Mo2 units in an approximately perpendicular orientation and mediate strong electrochemical communication between them. Each of the three compounds shows two quasireversible (μ-SO4) or fully reversible (μ-MoO4, μ-WO4) features in its cyclic voltammogram corresponding to successive oxidation of each of its Mo2 units. The ΔE1/2 values are the largest thus far measured for Mo2−X−Mo2 bridged complexes and may be sufficiently large to permit isolation of the singly oxidized species.