Selfstacking systems .6. Host lattice function of 2,3,8,9-tetramethoxydibenzo[c,e][1,2]-dichalcogenins in their electrically conducting iodine complexes

The structures of 2,3,8,9-tetramethoxydibenzo[c,e][1,2]dithiin (o-S-2, 1) and -diselenin (o-Se-2, 3) have been determined by single-crystal X-ray diffraction methods. Both compounds have a columnar structure in which the orientation of the molecules alternates with respect to their dichalcogeno bridges. The same kind of stacks had been found before in the electrically conducting iodine complex [o-S-2]I-1.16 (2) with channels parallel to the stacks in which chains of disordered polyiodide ions are intercalated, i.e. the host lattice of 2 is performed in 1. o-Se-2-(3) also forms an iodine complex of composition [o-Se-2]I-x (x = 1.5-2.5) (4) which is, however, thermally unstable loosing iodine already at room temperature. For reasons of comparison the X-ray structure of 3,3',4,4'-tetramethoxybiphenyl (5) has also been determined.