Bistability, low energy electron transter, and photomechanics: diimlne-bridged cobalt semiquinonate-catecholate coordination polymer

Summary form only given. Intramolecular shifts in charge distribution have been investigated for the Co/sup III/(N-N)(DBSQ) (DBCat)/Co/sup II/(N-N)(DBSQ)/sub 2/ tautomers for a series of N-donor coligands. Complexes have been studied that remain exclusively in the low-spin Co(III) and high-spin Co(II) limiting forms, with a series of intermediate species that exhibit Co(III)/Co(II) equilibria in solution and in the solid state. Solid state equilibria have been observed by monitoring changes in magnetism and the intensity of a low energy transition (2500nm) that appears characteristically for the Co(Ill) tautomers. This transition has been tentatively assigned as the Cat /spl rarr/ Co(III) CT band. Micromechanical effects that result from structural changes for individual complex units are propagated over the length of the polymer to give the photomechanical effect.