DIOXOPYRIMIDOTETRATHIAFULVALENE AND AMINOOXOPYRIMIDOTETRATHIAFULVALENE - PI-ELECTRON DONORS FOR DESIGN OF CONDUCTING MATERIALS CONTAINING INTRAMOLECULAR HYDROGEN-BONDS OF NUCLEIC-ACID BASE-PAIR TYPE

Dimethyl [2,4-dioxo(1 H,3 H)pyrimido]tetrathiafulvalene <((1)under bar )> and thyl-[2-amino-4-oxo(3H)pyrimido]tetrathiafulvalene <((4)under b ar)> form unusual inner salts by oxidation in the presence of bases. T he insoluble black-green betaines (2) under bar and (5) under bar reac t with acids to form cation radical salts. Betaine (2) under bar in th e presence of acid and bis-(ethylenedithio)tetrathiafulvalene forms th e unexpected double salt (8) under bar. In order to synthesise the cat ion radical salts of (1) under bar and (4) under bar, it is necessary to use the ultrasonic method owing to the insolubility of the starting compounds. Electrical measurements of the betaines and cation radical salts in pressed samples show an unexpectedly low resistivity with se miconducting character: for betaine (2) under bar rho(RT)= 840 Omega c m, for betaine (5) under bar rho(RT) = 10 Omega cm, for salt (7) under bar rho(RT)= 40 Omega cm, but for double salt (8) under bar rho(RT)= 50 Omega cm. In the case of salt (8) under bar, very low values of act ivation energy of electrical conductivity of the order of kT were obse rved. The synthesis and purification of tetrathiafulvalene (4) under b ar from no-7-oxo(GH)-1,3-dithiolo[4,5-d]pyrimidineselone-2 are describ ed. (C) 1997 by John Wiley & Sons, Ltd.