Copper hydrotris(3, 5-diphenylpyrazolyl)borate dithiocarbamates: mimicking green copper proteins. (18th December 2014)

• Record Type: Journal Article
• Authors: Harding, David J.; Phonsri, Wasinee; Harding, Phimphaka; Sirirak, Jitnapa; Tangtirungrotechai, Yuthana; Webster, Richard D.; Adams, Harry
• Is Part Of: New journal of chemistry. Volume 39:Number 2(2015:Feb.)
• Page Start: 1498
• Page End: 1505
• Publication Date: 2014-12-18
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c4nj01298d
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Three new copper hydrotris(pyrazolyl)borate dithiocarbamate complexes [Tp Ph2 Cu(dtc)] which mimic green copper proteins are reported. Abstract : Three novel copper hydrotris(3, 5-diphenylpyrazolyl)borate (Tp Ph2 ) dithiocarbamate complexes, [Tp Ph2 Cu(dtc)] (dtc = S2 CNEt2 1, S2 CNBz2 2 and S2 CN(CH2 )4 3 ) have been prepared in a simple one pot reaction by sequential addition of KTp Ph2 and Na(dtc) to CuCl2 ·2H2 O. IR, UV-Vis and ESR spectroscopic studies suggest a mostly κ 3 coordinated Tp Ph2 ligand, bidentate dithiocarbamate ligands and therefore, a five coordinate copper centre. Unusually, a κ 3 to κ 2 isomerisation of the Tp Ph2 ligand is found in solution in3 and to a lesser extent in1 . The X-ray crystal structures reveal geometries intermediate between trigonal bipyramidal and square pyramidal depending on the steric bulk of the dithiocarbamate ligand and a long Cu–N bond resulting in an asymmetrically bound Tp Ph2 ligand. Electrochemical studies reveal quasi-reversible one-electron oxidation and reduction to Cu(i ) with the reversibility and reduction potential strongly dependent on the dithiocarbamate. DFT calculations reveal a weakly antibonding Cu–S π* SOMO and a strongly antibonding Cu–S σ* LUMO consistent with the significant effect of the dithiocarbamate ligand on the electrochemical behaviour of these complexes.