New Copper(II) Complexes Including Pyridine-2,5 Acid: Synthesis, Spectroscopic, Thermal Properties, Crystal Structure and How These Complexes Interact with Purified PON 1 Enzyme

Abstract

We report the synthesis of two square-pyramidal copper(II) complexes, [Cu(2,5-pydc)(2-aepy)(H<inf>2</inf>O)]·H<inf>2</inf>O, 1, and [Cu(2,5-pydc)(2-ampy)(H<inf>2</inf>O)]·H<inf>2</inf>O, 2 (2-aepy = 2-(aminoethyl)pyridine, 2-ampy = 2-(aminomethyl)pyridine, 2,5-pydc = pyridine-2,5-dicarboxylic acid or isocinchomeronic acid). The synthesized complexes have been characterized by X-ray diffraction, FT-IR, elemental, and thermal analysis techniques. The crystal structure of 1 was established by X-ray analysis. Powder X-ray diffraction analysis showed that the complexes are pure. The inhibition of human serum paraoxonase 1 (PON 1, EC 3.1.8.1) enzyme with these complexes were investigated. We used diethyl 4-nitrophenyl phosphate as a substrate to measure the paraoxonase activity of PON 1 enzyme spectrophotometrically. Complexes 1 and 2 decreased the in vitro PON 1 activity with different inhibition mechanisms. Complexes 1 and 2 inhibited paraoxonase activity of this enzyme as competitively and noncompetitively, respectively. © 2016 Informa UK Limited, trading as Taylor & Francis Group.