Synthesis and characterization of a new pyrazine functionalized TTF derivative and crystal structure of its charge-transfer complex with iodine

Abstract

The new donor ligand 4,5-bis(2-pyrazylmethylsulfanyl)-4′,5′-bis(cyanoethylthio)tetrathiafulvalene ( 1) has been synthesized and characterized. The electrochemical properties of the ligand have been investigated by cyclic voltammetry (CV) and 1 shows two reversible oxidation processes at E 1 1 / 2 = 0.69 V and E 2 1 / 2 = 0.97 V (in DCM, versus Ag/AgCl). The charge-transfer complex ( 1 2) 2+[(I 2) 3/2I −] 2 · 2CH 2Cl 2 has been prepared by layer diffusion and characterized by X-ray crystallography. The oxidized ligand forms head-to-tail π-dimers which are embedded in layers of a 2D polyiodide network. The separation of these dimers by the anionic network and solvent molecules accounts for the insulating property of the charge-transfer complex.