title: Partial conversion of thioamide into nitrile in a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone), a drug prototype for Alzheimer's disease.
abstract: This work reports the crystal structure of [(Z)-2-((E)-1-{6-[1-({[amino(sulfanidyl-κS)methylidene]amino}imino-κN)ethyl]pyridin-2-yl-κN}ethylidene)-1-cyanohydrazinido-κN(1)]copper(II), [Cu(C11H11N7S)], the first description of a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone) showing partial conversion of a thioamide group to a nitrile group. The asymmetric ligand coordinates to the metal centre in an N,N',N'',S-tetradentate manner via the pyridine N atom, an imine N atom, the hydrazinide N atom and the sulfanidyl S atom, displaying a square-planar geometry. Ligand coordination results in two five-membered chelate rings and one six-membered chelate ring, and in crystal packing based on N-H···N hydrogen bonds of the cyanohydrazinide and hydrazinecarbothioamidate arms of the ligand. The correlation between the partial conversion upon metal complexation, H2S release and possible effects on the activity of bis(thiosemicarbazone)s as drug prototypes for Alzheimer's disease is also discussed.
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada.
authors.forename: Rafael P
authors.initials: RP
authors.lastname: Vieira
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada.
authors.forename: John R
authors.initials: JR
authors.lastname: Thompson
authors.affiliation: Departamento de Quimica, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Heloisa
authors.initials: H
authors.lastname: Beraldo
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6, Canada.
authors.forename: Tim
authors.initials: T
authors.lastname: Storr
mesh_terms: D000544:Alzheimer Disease / Q000188:drug therapy*; D056831:Coordination Complexes / Q000737:chemistry* / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D042963:Electron Transport Complex II; D013882:Thiosemicarbazones / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D056831:Coordination Complexes; D013882:Thiosemicarbazones; C000602490:copper(II) 2,6-diacetylpyridine bis(thiosemicarbazone); D042963:Electron Transport Complex II
keywords: Alzheimer's disease; bis(thiosemicarbazone); copper(II) complex; crystal structure; hydrogen sulfide generation; nitrile; partial conversion