0000000000007881
AUTHOR
Enrico Monzani
Functional superoxide dismutase mimics. Structural characterization and magnetic exchange interactions of copper(II)-N-substituted sulfonamide dimer complexes.
Dinuclear copper(II) complexes with N-substituted sulfonamide ligands as superoxide dismutase (SOD) mimics have 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 from these ligands, [Cu(2)(tz-tol)(4)] (1) and [Cu(2)(tz-naf)(4)] (2), have been synthesized, and their crystal structure, magnetic properties, and EPR spectra were studied in detail. In both compounds the metal centers are bridged by four nonlinear triatomic NCN groups. The coordination geometry of the coppers in the dinuclear entity of 1 and 2 is distorted square planar with t…
Reversible Dioxygen Binding and Phenol Oxygenation in a Tyrosinase Model System
The complex [Cu2(L-66)]2+ (L-66 = a,a'-bis¿bis[2-(1'-methyl-2'-benzimidazolyl)ethyl]amino¿-m-xylene) undergoes fully reversible oxygenation at low temperature in acetone. The optical [lambda(max) = 362 (epsilon 15000), 455 (epsilon 2000), and 550 nm (epsilon 900M(-1)cm(-1))] and resonance Raman features (760 cm(-1), shifted to 719cm(-1)(-1) with 18O2) of the dioxygen adduct [Cu2(L-66)(O2)]2+ indicate that it is a mu-eta2:eta2-peroxodicopper(II) complex. The kinetics of dioxygen binding, studied at - 78 degrees C, gave the rate constant k1 = 1.1M(-1) 5(-1) for adduct formation, and k(-1) =7.8 x 10(-5)s(-1), for dioxygen release from the Cu2O2 complex. From these values, the O2 binding consta…