Solution studies of copper(II) complexes as a contribution to the study of the active site of galactose oxidase

Abstract

Reportamos neste trabalho, a síntese, e a caracterização em solução dos compostos de coordenação de cobre(II) -[Cu II (H 2 bbpeten)](NO 3 ) 2 , [H 2 -(2-hydroxyethyl)ethane-1,2-diamine] -are reported as copper(II) complexes containing alcoholic, pyridine and phenolic arms. Two of the ligands bear a NO 2 group at the para position of one or two of the phenolic moieties. Electrochemical studies have been performed for the proligands and for the copper complexes. bbpeten = N-(2-hydroxybenzyl)-N,N'-bis(2-pyridylmethyl)-N'-(2-

Phosphorescent emissions of phosphine copper(I) complexes bearing 8-hydroxyquinoline carboxylic acid analogue ligands

“…Cyclic voltammograms for the complexes were recorded in the potential range from 1.2 to À 1.2 V. Complex (1) exhibited a sharp oxidation peak (Fig. 5) during the reverse scan at -0.33 V vs. Ag/AgCl with the typical features of a redissolution process [34,35]. However, for complexes (2) and (3) (Fig.…”

Two different modes for copper(II) ion coordination to quinine-type ligands

“…28 In the proposed structures, quinine binds to copper in a bidentate manner while hydroquinidine hydrochloride in a monodentate one.…”

Nitrite Reductase Activity in Engineered Azurin Variants

“…44 The A ∥ values of the variants were similar to those of other T2 Cu(II) proteins and slightly larger than those of native NiR T2 Cu(II) sites, which have A ∥ ≈ 110–150 G. 10,14,17,18,63,76–79 The EPR axial line shape and spectroscopic parameters of the azurin variant T2 Cu(II) centers were consistent with those of other five-coordinate copper sites of mixed nitrogen- and oxygen-donating ligands in a distorted-square-pyramidal geometry. 36,43,66–68,80 The readily discerned copper hyperfine splittings in the g ∥ region demonstrated a d x 2 – y 2 ground state common in T2 Cu(II) centers. 81 Small differences in the spectroscopic values between the variants reported here are likely results of the different residues in the four azurin variants in varied locations on the protein surface.…”

“…65–71 T2 Cu(II) centers in superoxide dismutase (SOD), for example, demonstrated broad Cu(II) d–d transitions at 670–700 nm, 66,72 and those of the trihelical peptides were around 640 nm, 34,35 while those of other N,O-rich square-pyramidal synthetic model complexes were ~650–720 nm. 36,43,68–70 The spectrum of a native NiR T2 copper center was reported to be 790 nm with an absorptivity of 85 M −1 cm −1 . 64 The absorptivity values of the T2 centers on azurin were low, as expected for Cu(II) d → d transitions.…”