3, Br and CF 3) on the structure, stability and redox property of [Cr(R-pic) 2(H 2O) 2]NO 3·H 2O complexes]]>

摘要

AbstractComplexes [Cr(3-CH3-pic)2(H2O)2]NO3·H2O (1), [Cr(5-Br-pic)2(H2O)2]NO3·H2O (2) and [Cr(5-CF3-pic)2(H2O)2]NO3·H2O (3) were synthesized (pic?=?pyridine-2-carboxylic acid) and characterized by X-ray crystal diffraction. Crystal structure indicates that two bidentate ligands occupy equatorial position and two H2O occupy axial positions intrans-configuration. (i) Decomposition of complexes1,2and3in different medium (phosphate buffered saline (PBS), apo-ovotransferrin (apootf) and EDTA) indicates that decomposition rate constants of these complexes follow the sequence of1?2?3. (ii) The redox potential of Cr(III)/Cr(II) by cyclic voltammetry follows the sequence of1(?1.20?V)?>?3(?1.29?V)?>?2(?1.31?V). (iii) In addition, ·OH-generation of the new synthesized complexes was determined by Fenton-like reaction in comparison with Cr(pic)3, and it may be related to the reduction potential of the complexes. (iv) Moreover, Hammett substituent constantsσp(inductive) andσm(resonance) (R?=?3-CH3, 5-Br, 5-CF3) were introduced to evaluate the impact of substituent groups on the bond length and decomposition kinetics. The substituent group on the ligand has great effect on the properties of the complexes.Graphical abstractDisplay OmittedHighlights?Three Cr(pic)3derivatives [Cr(R-pic)2(H2O)2]NO3·H2O were synthesized.?Decomposition in PBS, apo-ovotransferrin and EDTA were measured.?The redox potential of Cr(III)/Cr(II) by cyclic voltammetry were studied.?OH-generation by complexes was de