CONDUCTING LANGMUIR-BLODGETT-FILMS OF AN AMPHIPHILIC UNSYMMETRICAL ETHYLENEDITHIOTETRATHIAFULVALENE DERIVATIVE - EDT-TTF-CH2OC(O)C17H35

Langmuir-Blodgett (LB) films of the novel amphiphilic ethylenedithiote trathiafulvalene derivative [EDT-TTF-CH2OC(O)C17H35, 5] assembled on a range of solid substrates have room temperature in-plane dc conductiv ity values as high as sigma(rt)=10(-2)-10(-3) S cm(-1) as deposited; i odine doping results in an immediate decrease in conductivity to value s of sigma(rt)=ca. 10(-6) S cm(-1), which subsequently increases over a few hours to sigma(rt)=ca. 10(-3) S cm(-1), as a stable mixed-valenc e state is attained. The LB films have been characterized by ellipsome try, UV-VIS spectroscopy and cyclic voltammetry. By comparison with an alogous long-chain TTF and BEDT-TTF derivatives, it appears that the c arbonyl group in the side chain of 5 facilitates LB film formation, an d the ethylenedithio bridge of 5 contributes to the unusually high con ductivity of the as-deposited films, possibly due to the presence of n on-bonded, intermolecular S-S interactions. Analogous derivatives of t rimethyl-TTF and ethylenediseleno-TTF substituted with the same side-c hain, i.e., triMe-TTF-CH2OC(O)C17H35, 10, and EDS-TTF-CH2OC(O)C(17)H(3 )5, 11, respectively, form LB films with significantly lower conductiv ity values than 5, both before and after iodine doping.