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.

Electrochemical Synthesis of Nanosize Polypyrrole in Presence of Aqueous Surfactant Solutions

2013 ◽  
Vol 678 ◽  
pp. 244-247
Author(s):  
Jayaraman Anandha Raj ◽  
Raman Sasikumar ◽  
Malaisamy Sethupathy ◽  
Chinnapiyan Vedhi ◽  
Paramasivam Manisankar
Keyword(s):  
Hollow Structure ◽  
Particle Sizes ◽  
Cyclic Voltammetric ◽  
Sem Images ◽  
Polymer Formation ◽  
Irreversible Oxidation ◽  
Ft Ir ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies ◽  
Nano Size

Nano size Polypyrrole (PPY) was synthesized electrochemically in presence of three different surfactants namely CTAB, CSA and TTX-100. Cyclic voltammetric studies showed an irreversible oxidation of pyrrole in the presence of surfactants. The currents of the broad peak were 4.26mA, 5.3mA and 8.6mA for PPY/CTAB, PPY/CSA and PPY/TTY-100 respectively. The FT IR spectra of electrochemically synthesized PPY in presence and absence of surfactants were analyzed and the prominent peaks were assigned properly. The presence of N-H group in both cases suggests the presence of pyrrole units in the polymer. From the XRD results the particle sizes of all the four PPYs were determined and the values are as follows: PPY (34 nm), PPY/CSA (31 nm), PPY/CTAB (30nm), PPY/TTX-100 (29 nm). The PPY/TTX-100 exhibited highest electrical conductivity (2.04 ×10−3 S/cm) among other PPY synthesized (PPY/CTAB - 1.13 ×10−3 S/cm, PPY/CSA - 1.09×10−3 S/cm and PPY - 1.27 ×10−3 S/cm). SEM images of PPY/CSA showed agglomerated small polymeric fragments whereas PPY/CTAB showed large sized polymeric plates. Interestingly PPY/TTX–100 showed uniform hollow structure. The presence of surfactants has resulted in uniform polymer formation.

scholarly journals Spectroelectrochemical Properties and Catalytic Activity in Cyclohexane Oxidation of the Hybrid Zr/Hf-Phthalocyaninate-Capped Nickel(II) and Iron(II) tris-Pyridineoximates and Their Precursors

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 336
Author(s):  
Yan Z. Voloshin ◽  
Semyon V. Dudkin ◽  
Svetlana A. Belova ◽  
Daniel Gherca ◽  
Dumitru Samohvalov ◽  
...  
Keyword(s):  
Density Functional ◽  
Redox Activity ◽  
Oxidation Reactions ◽  
Paramagnetic Resonance ◽  
Molecular Systems ◽  
Near Ir ◽  
Voltammetric Studies ◽  
Cyclic Voltammetric Studies ◽  
Electron Paramagnetic

The in situ spectroelectrochemical cyclic voltammetric studies of the antimony-monocapped nickel(II) and iron(II) tris-pyridineoximates with a labile triethylantimony cross-linking group and Zr(IV)/Hf(IV) phthalocyaninate complexes were performed in order to understand the nature of the redox events in the molecules of heterodinuclear zirconium(IV) and hafnium(IV) phthalocyaninate-capped derivatives. Electronic structures of their 1e-oxidized and 1e-electron-reduced forms were experimentally studied by electron paramagnetic resonance (EPR) spectroscopy and UV−vis−near-IR spectroelectrochemical experiments and supported by density functional theory (DFT) calculations. The investigated hybrid molecular systems that combine a transition metal (pseudo)clathrochelate and a Zr/Hf-phthalocyaninate moiety exhibit quite rich redox activity both in the cathodic and in the anodic region. These binuclear compounds and their precursors were tested as potential catalysts in oxidation reactions of cyclohexane and the results are discussed.

Evaluation of systemic blood NO dynamics by EPR spectroscopy: HbNO as an endogenous index of NO

2003 ◽  
Vol 285 (2) ◽  
pp. H589-H596 ◽  
Author(s):  
Kazuyoshi Kirima ◽  
Koichiro Tsuchiya ◽  
Hiroyoshi Sei ◽  
Toyoshi Hasegawa ◽  
Michiyo Shikishima ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Whole Blood ◽  
Computer Assisted ◽  
Subtraction Method ◽  
Epr Spectrum ◽  
Systemic Blood ◽  
Paramagnetic Resonance ◽  
Species Overlap ◽  
Epr Signal ◽  
Electron Paramagnetic

The measurement of hemoglobin-nitric oxide (NO) adduct (HbNO) in whole blood by the electron paramagnetic resonance (EPR) method seems relevant for the assessment of systemic NO levels. However, ceruloplasmin and unknown radical species overlap the same magnetic field as that of HbNO. To reveal the EPR spectrum of HbNO, we then introduced the EPR signal subtraction method, which is based on the computer-assisted subtraction of the digitized EPR spectrum of HbNO-depleted blood from that of sample blood using the software. Rats were treated with Nω-nitro-l-arginine methyl ester (l-NAME; 120 mg · kg–1 · day–1) for 1 wk to obtain HbNO-depleted blood. When this method was applied to the analysis of untreated fresh whole blood, the five-coordinate state of HbNO was observed. HbNO concentration in pentobarbital-anesthetized rats was augmented (change in [HbNO] = 1.6–5.5 μM) by infusion of l-arginine (0.2–0.6 g/kg) but not d-arginine. Using this method, we attempted to evaluate the effects of temocapril on HbNO dynamics in an l-NAME-induced rat endothelial dysfunction model. The oral administration of l-NAME for 2 wk induced a serious hypertension, and the HbNO concentration was reduced (change in [HbNO] = 5.7 μM). Coadministration of temocapril dose dependently improved both changes in blood pressure and the systemic HbNO concentration. In this study, we succeeded in measuring the blood HbNO level as an index of NO by the EPR HbNO signal subtraction method. We also demonstrated that temocapril improves abnormalities of NO dynamics in l-NAME-induced endothelial dysfunction rats using the EPR HbNO signal subtraction method.

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