Review Article
Brandon Quillian, John W Haddo
Abstract
In an effort to better understand the steric impact of sterically bulky heterocyclic thioureas on group 11 transition metals, we began a study with 1-(2,6-xylyl)-2-imidazolidinethione. Reaction of 1-(2,6-xylyl)-2- imidazolidinethione (L) with chloroauric acid (HAuCl4) affords the cationic complex, [bis(1-(2,6-xylyl)-2-imidazolidinethione)gold(I)] chloride, [L2Au(I)] Cl [1], while reaction of L with either copper (II) bromide or chloride (CuBr2 and CuCl2) under similar conditions yields isostructural, trigonal planar, bis(1-(2,6-xylyl)-2-imidazolidinethione copper(I) halide complexes, (L2CuX; X=Br=2; X=Cl=3). Complex 1 crystallizes in the orthorhombic unit cell (Pbcn space group) and the crystal structure displays an essentially linear, twocoordinate gold atom [S(1)−Au−S(1?) bond angle=171.79(7)°] with the N−H groups of the ligand participating in intermolecular hydrogen bonds with the chloride anion. Compounds 2 and 3 are both isostructural and isomorphic, crystallizing in the primitive monoclinic cell in the P21/c space group with nearly identical unit cell dimensions. The crystal structures of 2 and 3 display a trigonal planar three coordinate copper atom with the ligands held in a “syn-periplanar” type conformation with respect to the C(N-aryl)−S...S−C(N-aryl) dihedral plane (13.149(9)? for 2 and 17.45(19)? for 3). Both N−H groups participate in intramolecular hydrogen bonding with each respective halogen in 2 and 3. All complexes were characterized by 1H and 13C NMR spectroscopy and IR spectroscopy, elemental analysis and single crystal X-ray crystallography.