Langmuir-Blodgett films of a tetrathiafulvalene derivative substituted with an azobenzene group

The new tetrathiafulvalene derivative 1, functionalised with an azobenzene substituent, has been synthesised. Cyclic voltammetric and spectroelectrochemical studies in solution demonstrate the reversible formation of the radical cation of 1. UV-VIS spectroscopy suggests that there is a weak interaction between the TTF and azobenzene moieties in compound 1, and demonstrates that trans-cis isomerisation occurs upon photolysis of the azobenzene substituent. Semi-conducting LB films of 1 have been assembled without the need for added fatty acid: room temperature conductivity values of the films before and after doping with iodine vapour were σ_rt = 10^-3-10^-5 S cm^-1 and 2 × 10^-2-10^-3 S cm^-1, respectively. No change in the conductivity of the LB films was observed under irradiation.