Heavy metal complexes of macrocyclic trithioethers

Abstract

We report here two crystal structures of heavy metal complexes containing macrocyclic trithioethers. The trithioether, 10S3 (1,4,7-trithiacyclodecane) complexes Pb(II) to form a compound of the formula [Pb(10S3)](ClO₄)₂(H₂O) (Compound 1). This behavior contrasts the related trithioether 9S3 (1,4,7-trithianonane), which readily forms a bis Pb(II) complex. Crystals of Compound 1 consist of [Pb(10S3)(H₂O)]²⁺ units and perchlorate anions which are weakly bound to the Pb²⁺ center. The two perchlorate anions serve as bidentate ligands to a single lead(II) center. However, a third oxygen in one of the perchlorates also serves as a bridging group between two lead(II) centers, linking the [Pb(10S3)(H₂O)]²⁺ units into zigzag chains. Thus, a highly irregular nine-coordinate (S₃O₆) environment around the Pb²⁺ion is formed by the three sulfur donors from the 10S3 ligand, one coordinated water, and five oxygens from three different perchlorate anions. Also, the lone pair electrons on the Pb center are stereochemically active. Compound 2, [Cd(9S3)₂](ClO₄)₂ ⋅ 2 CH₃NO₂, forms a distorted octahedral structure with unusual hexakis(thioether) coordination to the Cd(II) center. Bond distances and angles are very comparable to those found in the structure of the tetrafluoroborate salt of the complex cation. (1): P2₁/c, a = 9.1720(6) Å, b = 15.7687(11) Å, c = 11.8427(8) Å, β = 93.0180(10) ^○, V = 1710.4 (2) ų, Z = 4; (2): P2₁/c , a = 10.4305(10) Å, b = 15.2059(6) Å, c = 9.4919(7) Å, β = 99.324(9)^○, V = 1485.6(2) ų, Z = 2.