Preparation, characterization, and biologic evaluation of copper(II) – Schiff base complexes derived from anthranilic acid and aldoses

1993 ◽  
Vol 71 (5) ◽  
pp. 629-633 ◽  
Author(s):  
Mohammad S. Iqbal ◽  
Syed J. Khurshid ◽  
Mohammad Z. Iqbal
Keyword(s):  
Schiff Base ◽  
Anthranilic Acid ◽  
Spectroscopic Data ◽  
Spectral Lines ◽  
Schiff Base Complexes ◽  
Paramagnetic Resonance ◽  
Paw Oedema ◽  
Square Planar ◽  
Rhombic Distortion ◽  
Electron Paramagnetic

Cu(II) – Schiff base complexes containing anthranilic acid and aldoses (sugars) as part of the base were prepared and characterized by microanalytical, thermogravimetric, magnetic, and spectroscopic data. The complexes are four-coordinate, anhydrous, and ML2 type. The electron paramagnetic resonance spectral lines exhibited rhombic distortion from axial symmetry in the square-planar Cu(II) complexes with [Formula: see text] The complexes were found to be active against kaolin paw oedema and standard strains of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa.

Structural Variation and Magneto-Structural Correlation in Two New Dinuclear Bis(µ2-Phenoxo)-Bridged CuII Schiff-Base Complexes: Catalytic Potential for the Peroxidative Oxidation of Cycloalkanes

2010 ◽  
Vol 63 (3) ◽  
pp. 479 ◽  
Author(s):  
Subhra Basak ◽  
Soma Sen ◽  
Partha Roy ◽  
Carlos J. Gómez-García ◽  
David L. Hughes ◽  
...  
Keyword(s):  
Schiff Base ◽  
Exchange Interactions ◽  
Coupling Constants ◽  
Schiff Base Complexes ◽  
Schiff Base Ligands ◽  
Paramagnetic Resonance ◽  
Catalytic Potential ◽  
Elemental Analyses ◽  
Distorted Trigonal Bipyramid ◽  
Electron Paramagnetic

Two new dinuclear bis(μ2-phenoxo)-bridged copper(ii) complexes [Cu(NCS)L1]2 (1) and [Cu(NCS)L2]2 (2) have been synthesized using two tridentate NNO-donor Schiff-base ligands, L1H (Me2N(CH2)3N=CHC6H3(OMe)(OH)) and L2H (Me2N(CH2)3N=C(CH3)C6H4(OH)), respectively. They have been characterized by elemental analyses, IR, UV-visible, and electron paramagnetic resonance (EPR) spectroscopy, cyclic voltammetry, and magnetic susceptibility measurements. X-Ray single-crystal structures reveal a central Cu2O2 core in each complex with an isothiocyanate ligand coordinated terminally to each metal centre. The coordination environments around the CuII ions in 1 and 2 are a distorted trigonal bipyramid and a quasi-regular square pyramid, respectively, with significant differences in the Cu–O–Cu bridging angles (100.22(5)° for 1 and 95.64(7)° for 2). Although both CuII dimers present intradimer antiferromagnetic exchange interactions, the magnitudes of the coupling constants in 1 and 2 (J = –119(1) and –0.361(3) cm–1, respectively) are quite different as a result of the different coordination geometries and Cu–O–Cu bridging angles. Both complexes act as promising catalysts or catalyst precursors for the efficient peroxidative oxidation of cycloalkanes (cyclohexane and cycloheptane) to the corresponding cyclic alcohols and ketones, with maximum overall yields of 53% and 56% for 1 and 2, respectively.

Spectroscopic and Magnetic Properties of Gadolinium Macroacyclic and Macrobicyclic Complexes

2007 ◽  
Vol 128 ◽  
pp. 199-205
Author(s):  
G. Leniec ◽  
Slawomir M. Kaczmarek ◽  
J. Typek ◽  
Beata Kołodziej ◽  
Eugeniusz Grech ◽  
...  
Keyword(s):  
Schiff Base ◽  
Metal Ion ◽  
Molecular Spectroscopy ◽  
Schiff Base Complex ◽  
Schiff Base Complexes ◽  
Magnetic Interactions ◽  
Paramagnetic Resonance ◽  
Complex Samples ◽  
Integrated Intensity ◽  
Electron Paramagnetic

As a result of the Schiff base condensation the gadolinium macroacyclic and macrobicyclic Schiff base complexes have been synthesized and investigated by infrared spectroscopy (IR) and electron paramagnetic resonance (EPR). Both electron ionization and electron spray Molecular Spectroscopy spectra confirmed the [1:1] proportion of a ligand to metal in gadolinium macrocyclic and mocrobicyclic Schiff base complex samples. The thermogravimetrydifferential thermal analysis (TG-DTA) indicated the presence of two water molecules in the innersphere of the macrobicyclic complex and confirmed no water coordination of the metal ion in the macroacyclic complex. The temperature dependence of the integrated intensity of the EPR spectra enabled the magnetic interactions in the spin system of these compounds to be revealed.

Structural and spectropscopic studies of a three-dimensional hydrogen-bonded copper(II) complex: aqua[bis(pyridin-2-ylcarbonyl)amidato]cyanidocopper(II)

2015 ◽  
Vol 71 (2) ◽  
pp. 165-168 ◽  
Author(s):  
Jiang-Yun Wang
Keyword(s):  
Three Dimensional ◽  
Spectroscopic Studies ◽  
Epr Spectrum ◽  
Cyclic Voltammetric ◽  
Paramagnetic Resonance ◽  
Irreversible Oxidation ◽  
Square Planar ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies ◽  
Electron Paramagnetic

The preparation and X-ray and spectroscopic studies of the title copper(II) complex, [Cu(C12H8N3O2)(CN)(H2O)], are reported. The CuIIcation is five-coordinated, forming a distorted square-planar pyramid with an Addison τ parameter of 0.14. The UV–vis spectrum shows ad–dtransition of the CuIIcentre at 638 nm, and the electron paramagnetic resonance (EPR) spectrum confirms that the CuIIcation has an axial symmetry coordination and that the unpaired electrons occupy thedx2–y2orbital. Cyclic voltammetric studies show two irreversible oxidation and reduction peaks.

A cyanide-bridged heterometallic coordination polymer constructed from square-planar [Ni(CN)4]2−: synthesis, crystal structure, thermal decomposition, electron paramagnetic resonance (EPR) spectrum and magnetic properties

2016 ◽  
Vol 72 (7) ◽  
pp. 555-560 ◽  
Author(s):  
Ying-Lian Qin ◽  
Bin-Wu Yang ◽  
Gao-Feng Wang ◽  
Hong Sun
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Building Blocks ◽  
Transition Metal Ions ◽  
Supramolecular Network ◽  
Electron Configuration ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Design Elements ◽  
Square Planar ◽  
Electron Paramagnetic

Square-planar complexes are commonly formed by transition metal ions having ad8electron configuration. Planar cyanometallate anions have been used extensively as design elements in supramolecular coordination systems. In particular, square-planar tetracyanometallate(II) ions,i.e.[M(CN)4]2−(MII= Ni, Pd or Pt), are used as good building blocks for bimetallic Hofmann-type assemblies and their analogues. Square-planar tetracyanonickellate(II) complexes have been extensively developed withN-donor groups as additional co-ligands, but studies of these systems usingO-donor ligands are scarce. A new cyanide-bridged CuII–NiIIheterometallic compound, poly[[diaquatetra-μ2-cyanido-κ8C:N-nickel(II)copper(II)] monohydrate], {[CuIINiII(CN)4(H2O)2]·H2O}n, has been synthesized and characterized by X-ray single-crystal diffraction analyses, vibrational spectroscopy (FT–IR), thermal analysis, electron paramagnetic resonance (EPR) and magnetic moment measurements. The structural analysis revealed that it has a two-dimensional grid-like structure built up of cationic [Cu(H2O)2]2+and anionic [Ni(CN)4]2−units connected through bridging cyanide ligands. The overall three-dimensional supramolecular network is expanded by a combination of interlayer O—H...N and intralayer O—H...O hydrogen-bond interactions. The first decomposition reactions take place at 335 K under a static air atmosphere, which illustrates the existence of guest water molecules in the interlayer spaces. The electron paramagnetic resonance (EPR) spectrum confirms that the CuIIcation has an axial coordination symmetry and that the unpaired electrons occupy thed_{{{{x}^2}-y^2} orbital. In addition, magnetic investigations showed that antiferromagnetic interactions exist in the CuIIatoms through the diamagnetic [Ni(CN)4]2−ion.

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