Syntheses and Structures of Copper(I) and Copper(II)Complexes with N/S Multidentate Ligands:Relevance to the Active Site of Blue Copper Proteins

• Main Authors: CHIH-MING CHEN, 陳志銘
• Other Authors: 李位仁
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/98812611325233621870

碩士 === 國立臺灣師範大學 === 化學系 === 95 === The active site of the well known electron transferase blue copper protein, has a distorded tetrahedral geometry, which the Cu ion is coordinated to two histidine and one cysteine in an approximately trignoal plane and to a methionine at the axial position. In this study, we have synthesized the Cu(II) complexes, [Cu(BBMeMS)(CH3CN)2(H2O)](ClO4)2 (1) and [Cu(BBMeES)(CH3CN)(η1-ClO4)](ClO4) (2) by the reaction of Cu(ClO4)2•6H2O with the N2S(thioether) ligands, BBMeMS and BBMeES, respectively, to be the precursor to prepare synthetic mimics for the active site of the blue copper protein. As Cu(II) complexe 1 and 2 reacted with a series of thiolate ligands, colorless Cu(I) complexes, [Cu(η2-BBMeMS)- (CH3CN)](ClO4) (7) and [Cu(CH3CN)(μ-BBMeES)Cu(BBMeES)](ClO4)2 (8) were obtained at room temperature; whereas, a deep blue solution was observed at - 78℃. When Cu(II) complex 1 reacted with sodium diethyldit- hiocarbamate, a diethyldithiocarbamate coordinated Cu(II) complex [Cu- (BBMeMS)((C2H5)2NCS2)](ClO4)2 (3) and a Cu(I) complex 7 were isolated. We have also attempted to model the active site of the reduced form of blue copper protein by reacting complex 8 with thiobenzoate and 2-(trimethylsilyl)benzenethiolate , respectively. From NMR analysis of the products, two Cu(I)-thiolate complex [Cu(BBMeES)(C6H5COS-)] and [Cu(BBMeES)((CH3)3SiC6H4S-)] were expected. In addition, we have prepared two bidentate ligand: 1-methyl-2-(methy- lthiomethyl)-1H-benzimidazole (MMB) and Sodium(1-methylbenzimidazol- 2-yl)methanethiolate (L2) for modeling the active site of blue copper protein. We have obtained a Cu(II) complex [(η2-MMB)2Cu(η1-ClO4)](ClO4) (6) and a Cu(I) complex [(η2-MMB)(η1-MMB)Cu](ClO4) (9). In summary, we found that the thiolate ligands have a very high tendence to reduce a Cu(II) ion which were coordinated to the neutral bidentate or tridentate N/S ligands. It is very crucial to design an appropriate ligand, which can stabilized a Cu(II) ion, to mimic the coordination environment of the active site of blue copper protein.