title: Influence of inductive effects and steric encumbrance on the catecholase activities of copper(II) complexes of reduced Schiff base ligands.
abstract: A series of copper(ii) complexes derived from reduced Schiff base ligands has been synthesized and characterized by single-crystal X-ray diffraction and spectroscopic analyses. With the exception of [Cu(Ala5NO2)(H2O)] (), which crystallized as a mononuclear repeating unit, [Cu2L2(H2O)x(DMSO)y]·solvent (L = Ala5H (), Ala5OMe (), Ala5Cl (), Ala5Br (), Gly5Br (), Val5Br () and Leu5Br (), x = 1 or 2, y = 0 or 1, solvent = MeOH or DMSO and H2O) crystallized as phenoxo-bridged dinuclear building units containing Cu2O2 cores. In , , , and , the axial positions are occupied by solvent ligands and carboxylate oxygen atoms from adjacent dimers, resulting in the formation of 1D helical coordination polymers. In , a 2D network is constructed by utilizing weak CuO interactions (∼2.7 Å) with carboxylate groups. All complexes have been investigated for their catecholase activities with 3,5-DTBC, and they show significant catalytic activities except for . The catalytic activities are also observed to increase with increasing +I effects, as well as increase with increasing steric bulkiness on the α-carbon of the carboxylate group.
authors.affiliation: Department of Chemistry, 3 Science Drive 3. and National University of Singapore, Singapore 117543, Singapore. chmjjv@nus.edu.sg.
authors.forename: Yude
authors.initials: Y
authors.lastname: Thio
authors.forename: Xiandong
authors.initials: X
authors.lastname: Yang
authors.forename: Jagadese J
authors.initials: JJ
authors.lastname: Vittal
mesh_terms: D004156:Catechol Oxidase / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008024:Ligands; D012545:Schiff Bases / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D012545:Schiff Bases; D003300:Copper; D004156:Catechol Oxidase