Role of the coordination center in photocurrent behavior of a tetrathiafulvalene and metal complex dyad.

Small organic molecule-based compounds are considered to be promising materials in photoelectronics and high-performance optoelectronic devices. However, photoelectron conversion research based on functional organic molecule and metal complex dyads is very scarce. We design and prepare a series of compounds containing a tetrathiafulvalene (TTF) moiety substituted with pyridylmethylamide groups of formulas [Ni(acac)2L]·2CH3OH (1), [Cu2I2L2]·THF·2CH3CN (2), and [MnCl2L2]n·2nCH3CH2OH (3) (L = 4,5-bis(3-pyridylmethylamide)-4',5'-bimethylthio-tetrathiafulvalene, acac = acetylacetone) to study the role of the coordination center in photocurrent behavior. Complex 1 is a mononuclear species, and complex 2 is a dimeric species. Complex 3 is a two-dimensional (2-D) coordination polymer. Spectroscopic and electrochemical properties of these complexes indicate that they are electrochemically active materials. The tetrathiafulvalene ligand L is a photoelectron donor in the presence of electron acceptor methylviologen. The effect of metal coordination centers on photocurrent response behavior is examined. The redox-active metal coordination centers should play an important role in improvement of the photocurrent response property. The different morphologies of the electrode films reflect the dimensions in molecular structures of the coordination compounds.