Molecular metals based on pd(dddt)/sub 2/ complexes

Summary form only given. The M(dddt)/sub 2/ complexes (dddt2- = 5,6-dihydro-1,4dithiin-2,3 dithio late) arouse great interest for they are isolobal analogs of the molecule BEDT-TTF [1] which is known to form superconducting cation radical salts [2]. In this work the first cation salts of Pd(dddt)/sub 2/ with the anions different in their geometry and electronic configuration (IBr/sub 2/, C10/sub 4/, ZnC1O/sub 4/, PF/sub 6/, SnC1/sub 6/ etc) were prepared by electrochemical oxidation of Pd(dddt)/sub 2/ neutral complex. Some of them were found to be molecular metals. Properties and structure of Pd(dddt)/sub 2/ cation salts were compared with those of BEDT-TTF and Pt(dddt)/sub 2/ ones. In contrast to the latters with the octahedral doubly charged anions, which are dielectric at Low temperatures, Pd(dddt)/sub 2/ salt with TeC1/sub 6//sup 2-/ has high conductivity at 4.2 K (20 /spl Omega//sup -1/cm/sup -1/).