Xanthate sulfur as a hydrogen bond acceptor: the free xanthale anion and ligand sulfur in nickel tris ethylxanthate

摘要

Xanthates, like thiolates, form a variety of complexes with metals in which coordinating sulfur can serve as a hydrogen bond acceptor. Nickel tris xanthate complexes [Ni(xan)(3)](-), (xan = o-ethylxanthate, N-(carbamoylmethyl)ethylxanthate) have been synthesized and compared by a combination of X-ray crystallographic and spectroscopic measurements. Recent results from our studies of N-H (...) S hydrogen bonding interactions in metal-xanthate complexes shows N-S distances to be longer than those in related thiolate complexes, indicative of weaker hydrogen bonds for the xanthates. The complex (Et4N)[N-(carbomoylmethyl)ethylxanthate)] adopts an extended conformation in both the solid state and solution and lacks either intraligand or intermolecular N-H (...) S hydrogen bonds. The complex (CTA)[Ni(exa)(3)] exhibits N-H (...) S hydrogen bonds between the amide group of the counterion and the ligand sulfur. The amide-sulfur N-H (...) S distance is 3.567 Angstrom. (C) 2004 Elsevier B.V. All rights reserved.