SYNTHESIS AND X-RAY CRYSTAL-STRUCTURES OF HEAVY-METAL COMPLEXES OF 1,5,9,13-TETRATHIACYCLOHEXADECANE

Heavy-metal complexes of the macrocyclic tetrathioether 1,5,9,13-tetrathiacyclohexadecane (16S4) have been prepared by reaction of the ligand with the appropriate heavy-metal salts. The complexes [Hg(16S4)](ClO4)2, [Cd(16S4)](ClO4)2, and (16S4)(HgCl2)2 have been synthesized and characterized. Single-crystal X-ray structural studies have been carried out on [Hg(16S4)](ClO4)2 and [Cd(16S4)](ClO4)2. Crystal data for [Hg(16S4)](ClO4)2; C12H24S4HgCl2O8; monoclinic space group C2/c; a = 10.033 (3), b = 13.421 (4), c = 15.960 (4) angstrom, beta = 96.48 (2)-degrees; Z = 4; R = 0.051. Crystal data for [Cd(16S4)](ClO4)2; C12H24S4CdCl2O8; triclinic space group P1BAR; a = 8.346 (2), b = 8.349 (3), c = 8.688 (2) angstrom; alpha = 69.87 (2), beta = 68.97 (2), gamma = 82.33 (2)-degrees; Z = 1; R = 0.043. Molecular mechanics calculations have been carried out on the 16S4 ligand, and the lowest energy conformation is a quadrangular [4444] conformation with the sulfur atoms occupying the corners (exodentate) of the quadrangle.