M2 δ-to-oxalate π* conjugation in oxalate-bridged complexes containing M–M quadruple bondsElectronic supplementary information (ESI) available: Table of irreducible representations for [M2]n(OXA)n − 1 for all values of n. Fig. S1: plots of the frontier molecular orbitals of the D2h linear [Mo2]4(OXA)3 system and the D4h square [Mo2]4(OXA)4 system. See http://www.rsc.org/suppdata/cc/b1/b103898m/Dedicated to Professor Ernest R. Davidson on the occasion of his 65th birthday.

Abstract

The electronic structures of oxalate-bridged, quadruply-bonded dimolybdenum and ditungsten compounds have been investigated by a variety of computational methods employing density function theory (gradient corrected and time-dependent) which reveal the consequences of strong mixing of M₂ δ and oxalate π orbitals within extended chains and cyclic structures.