Spin-chemical effects on intramolecular photoinduced charge transfer reactions in bisphenanthroline copper(i)-viologen dyad assemblies.

Two covalently linked donor-acceptor copper phenanthroline complexes (C-A dyads) of interest for solar energy conversion/storage schemes, [Cu(i)(phen(OMV) )] = CA with C = [Cu(i)phen] involving 2,9-methyl (R = Me) or 2,9-phenyl (R = Ph)-phenanthroline ligands that are 5,6-disubstituted by 4-(-butoxy) linked methylviologen electron acceptor groups (A = OMV), have been synthesized and investigated quantum chemical calculations and nanosecond laser flash spectroscopy in 1,2-difluorobenzene/methanol (dfb/MeOH) mixtures. Upon photoexcitation, charge transfer (CT) states CAA are formed in less than one ns and decay by charge recombination on a time scale of 6-45 ns. The CT lifetime of CAA has a strong dependence on MeOH solvent fraction when R = Me, but is unaffected if R = Ph.

Cyclic voltammetric study of cobalt poly-4-t-butylpyridine ligand complexes on glassy carbon electrodes: electrolyte dependence and mechanistic considerations.

Polypyridyl complexes of Co(II/III) have been gaining prominence as potential replacements for I(-)/I(3)(-) as mediators in dye sensitized solar cells. In that regard, homoleptic pseudo-octahedral complexes of 4,4'-di-t-butyl-2,2'-bipyridine, [Co(DTB)(3)](2+/3+), and 4,4',4″-tri-t-butyl-2,2':6,2″-terpyridine, [Co(TTT)(2)](2+/3+), have been of particular interest. These complexes show extreme electrode surface and electrolyte dependent electrochemical behavior.