Chalcogenation of tetrathiafulvalene (TTF): synthesis of alkylthio-TTF and alkylseleno-TTF derivatives and X-ray crystal structure of ethylenediseleno TTF (EDS-TTF)

Abstract

The reaction of mono-lithiated tetrathiafulvalene (TTF) with elemental sulfur or elemental selenium at –78 °C yields the transient species TTF-S^– Li⁺ and TTF-Se^– Li⁺, respectively, which have been trapped with a range of alkyl halides to yield new alkylthio- and alkylseleno-TTF derivatives. Reaction of the TTF-thiolate anion with 2-bromoethanol yields 4-(2-hydroxyethylthio)tetrathiafulvalene which is a particularly versatile building block for the synthesis of a range of new mono-functionalised TTF derivatives containing ether, ester, acrylate, urethane and vinylthio groups in the side chain. Onepot syntheses of ethylenedithio-TTF (EDT-TTF) and ethylenediseleno-TTF (EDS-TTF) from TTF are reported. The structure of EDS-TTF has been determined by single crystal X-ray analysis which reveals dimers with molecular planes orthogonal to each other.