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.