Functional Superoxide Dismutase Mimics. Structural Characterization and Magnetic Exchange Interactions of Copper(II)-N-Substituted Sulfonamide Dimer Complexes

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• 作者：R. Cejudo-Marí ; n ; G. Alzuet ; S. Ferrer ; J. Borr&aacute ; s ; A. Casti&ntilde ; eiras ; E. Monzani ; and L. Casella
• 刊名：Inorganic Chemistry
• 出版年：2004
• 出版时间：October 18, 2004
• 年：2004
• 卷：43
• 期：21
• 页码：6805 - 6814
• 全文大小：198K
• 年卷期：v.43,no.21(October 18, 2004)
• ISSN：1520-510X

文摘

Dinuclear copper(II) complexes with N-substituted sulfonamide ligands as superoxide dismutase (SOD) mimicshave been investigated. The new N-(thiazol-2-yl)toluenesulfonamide (Htz-tol) and N-(thiazol-2-yl)naphthalenesulfonamide (Htz-naf) ligands have been prepared and structurally characterized. The complexes derived fromthese ligands, [Cu₂(tz-tol)₄] (1) and [Cu₂(tz-naf)₄] (2), have been synthesized, and their crystal structure, magneticproperties, and EPR spectra were studied in detail. In both compounds the metal centers are bridged by fournonlinear triatomic NCN groups. The coordination geometry of the coppers in the dinuclear entity of 1 and 2 isdistorted square planar with two N-thiazole and two N-sulfonamido atoms. Magnetic susceptibility data show astrong antiferromagnetic coupling, with -2J = 121.3 cm^-1 for compound 1 and -2J = 104.3 cm^-1 for compound2. The EPR spectra of the polycrystalline samples of compounds 1 and 2 have been measured at the X- andQ-band frequencies at different temperatures. Above 20 K the spectra are characteristic of S = 1 species withzero-field splitting parameter D = 0.230 cm^-1 for compound 1 and 0.229 cm^-1 for compound 2. The EPR parametersare discussed in terms of the known binuclear structures. The complexes exhibit high SOD activity, as shown bythe low IC₅₀ values obtained with the xanthine/xanthine oxidase/NBT assay: 0.13 ntities/mgr.gif">M for compound 1; 0.17 ntities/mgr.gif">Mfor compound 2.