Partial conversion of thioamide into nitrile in a copper(II) complex of 2,6-diacetylpyridine bis(thiosemicarbazone), a drug prototype for Alzheimer's disease

• Published in: Acta crystallographica. Section C, Crystal structure communications Vol. 71; no. Pt 6; p. 430
• Main Authors: Vieira, Rafael P, Thompson, John R, Beraldo, Heloisa, Storr, Tim
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01.06.2015
• Subjects: Alzheimer Disease - drug therapy; Coordination Complexes - chemistry; Coordination Complexes - pharmacology; Crystal structure; Crystallography; Crystallography, X-Ray; Electron Transport Complex II; Hydrogen bonds; Ligands; Thiosemicarbazones - chemistry; Thiosemicarbazones - pharmacology; crystal structure; bis(thiosemicarbazone); partial conversion; hydrogen sulfide generation; nitrile; Alzheimer's disease; copper(II) complex
• ISSN: 0108-2701; 2053-2296; 1600-5759
• DOI: 10.1107/S205322961500813X

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.