Mn(III) and Mn(II) complexes of tridentate Schiff base ligands; synthesis, characterization, structure, electrochemistry and catalytic activity

Modification of Glassy Carbon Electrodes with Complexes of Manganese(II) with Some Phenanthroline Derivatives Immobilized in Nafion Layer

Manganese(II) complexes with phenanthroline derivatives modified with different substituents were synthesized and incorporated into Nafion layers covering the surfaces of glassy carbon electrodes and were studied electrochemically. Formal potentials and apparent diffusion coefficients were calculated and discussed. The suitability for electrocatalytic oxidation of ascorbic acid and glycolic acid was examined. The surfaces of modified electrodes were characterized using atomic force microscopy.

The crystal and molecular structures of three copper-containing complexes and their activities in mimicking galactose oxidase

The structures of three copper-containing complexes, namely (benzoato-κ²O,O')[(E)-2-({[2-(diethylamino)ethyl]imino}methyl)phenolato-κ³N,N',O]copper(II) dihydrate, [Cu(C₇H₅O₂)(C₁₃H₁₉N₂O)]·2H₂O, 1, [(E)-2-({[2-(diethylamino)ethyl]imino}methyl)phenolato-κ³N,N',O](2-phenylacetato-κ²O,O')copper(II), [Cu(C₈H₇O₂)(C₁₃H₁₉N₂O)], 2, and bis[μ-(E)-2-({[3-(diethylamino)propyl]imino}methyl)phenolato]-κ⁴N,N',O:O;κ⁴O:N,N',O-(μ-2-methylbenzoato-κ²O:O')copper(II) perchlorate, [Cu₂(C₈H₇O₂)(C₁₂H₁₇N₂O)₂]ClO₄, 3, have been reported and all have been tested for their activity in the oxidation of D-galactose. The results suggest that, unlike the enzyme galactose oxidase, due to the precipitation of Cu₂O, this reaction is not catalytic as would have been expected. The structures of 1 and 2 are monomeric, while 3 consists of a dimeric cation and a perchlorate anion [which is disordered over two orientations, with occupancies of 0.64 (4) and 0.36 (4)]. In all three structures, the central Cu atom is five-coordinated in a distorted square-pyramidal arrangment (τ parameter of 0.0932 for 1, 0.0888 for 2, and 0.142 and 0.248 for the two Cu centers in 3). In each species, the environment about the Cu atom is such that the vacant sixth position is open, with very little steric crowding.

The crystal structure of bis-[(E)-4-bromo-2-({[2-(pyridin-2-yl)eth-yl]imino}-meth-yl)phenol]nickel(II) bis-[(E)-4-bromo-2-({[2-(pyridin-2-yl)eth-yl]imino}-meth-yl)phenolato]nickel(II) bis(perchlorate) methanol monosolvate, a structure containing strong inter-species hydrogen bonds

The title compound, [Ni(C14H12BrN2O)2][Ni(C14H13BrN2O)2](ClO4)2·CH3OH consists of two mononuclear ([Ni(HL)2]2+ and [NiL2]) complex mol-ecules linked by strong hydrogen bonding [O⋯O separations of only 2.430 (5) Å], which is the shortest reported to date for such species. In one of the complexes, both the coordinated phen-oxy groups retain their protons and thus this is the cationic equivalent species of the other complex where both coordinated phen-oxy groups are deprotonated. In addition, perchlorate anions are present for charge balance, as well as methanol solvate mol-ecules. For the neutral NiL2 complex, each 2-ethyl-amine-pyridine arm is disordered over two equivalent conformations with occupancies of 0.750 (8):0.250 (8). The perchlorate anion is disordered over two equivalent conformations with occupancies of 0.602 (8):0.398 (8). The perchlorate ions also link to the H atoms on the methanol methyl and hydroxyl groups. These inter-actions link the moieties into a complex three-dimensional array. The crystal studied was refined as a two-component twin.