Synthetic Metals, 41-43 (1991) 2205-2209 2205 SYNTHESIS AND STUDY 0F ISOMERIC MUbTISULFUR ~-DONORS BTDM-TTF AND BET-TT~ AND T~EIR CT COMPLEXES. N. SANTALO, J. VECIANA and C. ROVIRA Centre d'Investlgaci6 i Desenvolupament, C.S.I.C., Jordl Girona 18-26, 08034 Barcelona (Spain) E. MOLINS and C. MIRAVITLLES Instltut de Ci~ncla de Materials de Barcelona, C.S.I.C., Mart[ i Franqu~s s/n, 08028 Barcelona (Spain) J. CLARET Departament de Qu~mlca-F~sica, Universitat de Barcelona, Martl i Franqu~s I, 08028 Barcelona (Spain) ABSTRACT A synthetic route that allows to obtain four different multlsulfur ~- organic donors based on the tetrathiafulvalene structure is given. The synthesized donors which have one sulphur atom in each of the outer rings, are BTDM-TTF [I], trans- BET-TTF [2], and their aromatic counterparts; i.e., DT-TTF [3] and a-T-TTF [2]. Structure of trans-BET-TTF has been confirmed by single crystal X-ray diffraction. Generation and EPR characterizations, both in solution and in the solid state of their catlon-radlcals are also presented. INTRODUCTION The recent discoveries of organic superconductors based in multisulfur molecules (ET, DMET, MDT-TTF, and [M(dmit)2lX') [4] have aroused a large interest in the field of molecular metals. The suppression of Metal-Insulator (M-I) transitions is the first barrier to be overcome in order to obtain molecular superconductors. Intermolecular interactions between multisulfur n-donors molecules usually enhance the dlmenslonallty of their salts permitting the suppression of such M-I transitions and, therefore, allowing that transitions to the supercon- ducting state occur. The outer sulphur atoms in these molecules play an essential role in such intermolecular interactions [5-7]. The position of the outer sulphur atoms as well as the size of the cyclic substituents in TTF skeleton can also 0379-6779/91~3.50 O Elsevier Sequoia/Printed in The Netherlands