Synthesis of highly functionalised tetrathiafulvalenes

Abstract

A range of functionalised symmetrical and unsymmetrical tetrathiafulvalene (TTF) derivatives containing substituted 4,5-(propylene- 1,3-dithio) units fused to the TTF framework has been prepared. In particular, TTF derivatives bearing hydroxy or ketone functionality have been obtained. Cyclic voltammetric studies establish that the new TTF derivatives are efficient π-electron donors; they undergo two reversible, single-electron redox waves. A series of new bis- and tris-tetrathiafulvalene derivatives has been prepared. The TTF-thiolate anion has been used as a key intermediate and shown to be a particularly versatile reagent for this purpose. 4-(Benzoylthio) tetrathiafulvalene has been prepared and serves as a convenient shelf-stable precursor of the TTF-thiolate anion. A novel pentakis-tetrathiafulvalene macromolecule has been efficiently synthesised. The solution electrochemistry of the new multi-TTF derivatives has been studied by cyclic voltammetry, which reveals that the TTF moieties do not interact to any significant extent. Methodology has been developed for the preparation of highly functionalised analogues of TTF containing the 9,10-bis(l,3-dithiol-2- ylidene)-9,l 0-dihydroanthracene unit. These are versatile electron donor systems and have been used in the construction of novel redox assemblies.