Selenium analogues of DTEDT as promising donors for organic metals

Three selenium analogues of bis-fused donor DTEDT have been synthesized. They showed four pairs of single-electron redox waves. The E1 values are a little higher by 0.02–0.05 V than that of DTEDT (+0.37 V). On the other hand, the E2-E1 values (0.12–0.13 V) are almost equal to that of DTEDT (0.13 V). TCNQ complex and cation radical salts of them show fairly high electrical conductivities (10−1–102 S-cm−1) and several salts show metallic conducting behavior down to 1.5–4.2 K. An X-ray crystal structure analysis of a metallic salt (DSEDS)3TaF6 reveals that this salt has two-dimensional β-type packing motif of donor molecules.