SYNTHESIS AND CRYSTAL-STRUCTURE OF A THALLIUM(I) HYDROGEN BENZOTHIAZOLYLCYANOXIMATE COMPLEX WITH 18-CROWN-6 - THE THALLIUM ATOM IS IN THE CENTER OF THE CROWN-ETHER CAVITY

Complexes of composition [TI(18-crown-6){BTCO}] and [TI(18-crown-6){H( BTCO)(2)}] (BTCO = {ONC(CN)-(benzothiazolyl-2)}(-)) have been prepared . The crystal and molecular structure of the [TI(18-crown-6){H(BTCO)(2 )}] complex has been determined from X-ray diffraction data (orthorhom bic, space group Pbca, with a = 15.520(3), b = 11.668(2), c = 19.661(4 ) Angstrom, V = 3560.4(12) Angstrom(3), Z = 4). The structure was refi ned by least-squares methods to a final value of R = 0.029 based on 25 25 independent reflections with I > 2 sigma(I). The metal atom occupie s a center of symmetry. The lattice consists of centrosymmetric cation s TI(18-crown-6)(+) and anions {H(BTCO)(2)}(-), which are bridges betw een neighboring cations to give a one-dimensional polymeric structure. The thallium atoms adopt the eight-fold coordination of a slightly di storted hexagonal-bipyramidal geometry with axial nitrile nitrogen ato ms and reside exactly in the center of the crown ether (TI-O similar t o 2.820-2.876 Angstrom, TI-N 2.987 Angstrom). No stereochemical activi ty of a lone pair electron density of TI was observed.