BENZIMIDAZOLENE-2-THIONES - A NEW CLASS OF MOLECULES FOR THE ENGINEERING OF MOLECULAR TAPES IN THE ORGANIC-SOLID STATE

Derivatives of benzimidazolene-2-thione differing in substitution at t he 4 and 5 positions have been synthesized and studied by single-cryst al X-ray diffraction and/or X-ray powder diffraction. These derivative s include five monosubstituted compounds (l-SX; X = Me, F, CI, Br, I), four disubstituted compounds (1-SX2; X = Me, F, Cl, Br), the parent d ihydro compound (1-SH2), and the naphthyl compound (2-SH2). Five of th ese molecules gave crystals suitable for single-crystal X-ray diffract ion. In all of these crystals, the molecules pack as parallel, hydroge n-bonded tapes, Alternate molecules of a tape occupy two different pla nes that are separated by approximately 1 Angstrom. The resulting stru cture is named a stepped tape. These stepped tapes are divided into tw o classes based on packing: tapes of 1-SH2, 1-SMe2, and 1-SF pack in f lat, parallel planes. Tapes; of 2-SH2, 1-SF2, and 1-SCl2 pack at an an gle; of these, two (2-SH2 and 1-SF2) incorporate molecules of solvent. None of the structures is isomorphic.