Investigations of the tetrathiafulvalene (TTF) derivatives extended by the sigma -bond frameworks, such as saturated heterocycles (3-8) and alkyl groups (9), have been undertaken to explore new molecular-based organic metals. TTF donors with the periphery extended by the cis-fused dioxane ring (3) and by linkage of a dichalocogenolane or dioxane ring (4-6 or 7) produce metallic radical-cation salts. While radical-cation salts of the methylated TTF donor (9a) are semiconductive, the ClO4 and PF6 salts of the ethylated one (9b) exhibit metallic conducting behavior for compressed pellets. The crystal structure of the metallic (4)(2)AsF6 salt is also presented.
New Tetrathiafulvalene Donors with Extended Peripheral Substituents by Addition of Heterocycles: Synthesis, Properties, and Molecular Structures
Syntheses of the bis(heterocycle)-fused bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) derivatives 7 and 8, the heterocycle-fused BEDT-TTF, methylenedithio(ethylenedithio)tetrathiafulvalene (MET), and ethylenedithiotetrathiafulvalene derivatives 9-11, and the 1,3-dioxolane derivative of MET 12a and its analogues 12b-d are described. The heterocycle-fused ketones 17 and 19 with cis ring fusions could be prepared by the BF3-promoted reaction of tin dithiolate 13 with dihaloheterocycles 15 and 16 in good yields, respectively, and served as key intermediates for the (RO)(3)P- and/or Me3Al-promoted coupling syntheses of these new tetrathiafulvalene donors 7-12. Further, the electrochemical properties of new donors 8-12 by the use of cyclic voltammetry and the molecular structures of 9a, 10a, ii, and 12a by X-ray crystallographic analyses are also reported.
A New Approach to the Construction of BEDT-TTF Derivatives Condensed with Heterocycles via BF3-promoted Reactions of Organotin Thiolates
The synthesis of BEDT-TTF derivatives fused with heterocycles (3–7) has been accomplished via the BF3-promoted reaction of organotin thiolates (8 and 9) with electrophiles (10 and 11). Electrical conductivities of radical cation salts derived from some of them were also investigated.