The pyridazine-tetrathiafulvalene conjugates: synthesis, photophysical, and electrochemical properties

To study the electronic interactions in donor acceptor (D A) conjugates as a precursor of optoelectronic materials, a series monopyridazine-annulated tetrathiafulvalenes and a bispyridazine-annulated tetra-thiafluvalene were synthesized by a condensation reaction of 2,3-dimethoxycarbonyl-6,7-dibutylthiotetrathiafulvalene or/and 2,3,6,7-tetramethoxycarbonyltetrathiafulvalene with hydrazine hydrate and structurally characterized by conventional chemical and physical methods. Their electronic properties have been studied experimentally by the combination of electrochemistry and UV-vis spectroscopy. All of monopyridazine-tetrathiafulvalene conjugates 7-13 show intramolecular charge transfer interaction in ground states, which is rationalized on the basis of density functional theory. Their HOMO energy levels and Er values were estimated to be -4.88 to -5.07 eV from cyclic voltammetry and 2.43-2.79 eV from the absorption spectra, respectively. The X-ray crystallographic analyses of the pyridazine tetrathiafulvalene conjugates 7, 11-13 are also reported. (C) 2011 Elsevier Ltd. All rights reserved.