Synthesis of O,O Ethane Bridged Bis-copper(II) Macrocycles. Selective Enzyme Model for Catecholase Activity

Autor: Shamima Parveen, Sartaj Tabassum, Farukh Arjmand, Shaiba Parveen, Mala Chauhan
Rok vydání: 2006
Předmět:
Zdroj: Transition Metal Chemistry. 31:237-245
ISSN: 1572-901X
0340-4285
DOI: 10.1007/s11243-005-6393-0
Popis: New mononuclear and dinuclear complexes [3-hydroxyethyl-1,3,5,8,11pentaazacyclotridecane]copper(II) (1)/nickel(II) (2) perchlorate and O,O ethane bridged bis-copper(II) (3)/nickel(II) (4) macrocycles have been synthesized and characterized by various spectroscopic techniques, viz. i.r., n.m.r., e.p.r., u.v.–vis. and conductance measurements. Spectral data and conductance measurements reveal that all the complexes are consistent with square-planar geometry and are ionic in nature. The catalytic activity of the dinuclear Cu(II) complex (3) in the presence of pyrocatechol was determined spectrometrically by monitoring the increase of the o-benzoquinone characteristic absorption band at 25,000 cm−1 with respect to time in DMF saturated with molecular oxygen. The kinetic parameters Vmax (2.8×10−3 M s−1) and KM (1.4×10−3 mm) have been determined by Michaelis–Menten method. Electrochemistry of the dinuclear Cu(II) complex has been studied in the presence of molecular oxygen with pyrocatechol and without pyrocatechol at a scan rate of 0.1 V s−1 by cyclic voltammetry. On addition of pyrocatechol, complex shows a shift in Epc, Epa and E1/2 values indicating the oxidation of substrate (pyrocatechol).
Databáze: OpenAIRE
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