scholarly journals Copper(II) Complexes of Organophoshonic Acids-A Comparative Study

2011 ◽  
Vol 8 (s1) ◽  
pp. S271-S281
Author(s):  
B. Venkateswara Rao ◽  
D. M. Puri
Keyword(s):  
Phosphonic Acid ◽  
Octahedral Geometry ◽  
Spectral Studies ◽  
Diphosphonic Acid ◽  
Paramagnetic Resonance ◽  
Diethylene Triamine ◽  
Coordination Sites ◽  
Infrared Spectral ◽  
Electron Paramagnetic ◽  
Derivatives Of

Polynuclear copper(II) derivatives of 1-hydroxyethylidenediphosphonic acid (HEDP), 1-aminoethylidenediphosphonic acid (AEDP, H4L),α-aminobenzylidene diphosphonic acid (ABDP, H4L), 1-amino-2-carboxyethane- 1,1-diphosphonic acid (ACEDP, H5L), 1,3 diaminopropane-1,1,3,3-tetra-phosphonic acid (DAPTP, H8L), Ethylenediamine-N,N'-bis (dimethyl-methylenephosphonic) acid (EDBDMPO, H4L),o-phenylene-diamine-N,N'-bis (dimethylmethylenephosphonic) acid (PDBDMPO, H4L), diethylene triamine –N,N,N',N',N"N-penta (methylene phosphonic) acid (DETAPMPO, H10L) and diethylene triamine –N,N"-bis (dimethyl methylene phosphonic) acid (DETBDMPO, H4L) have been prepared in aqueous medium. The general formula of derivatives from elemental analysis was found to be Cu2L.XH2O (in case of AEDP, ABDP, EDBDMPO, PDBDMPO, DETBDMPO), Cu5L2.XH2O (in case of ACEDP) Cu4L.XH2O, Cu2H4L. XH2O (in case of DAPTP) and Cu5L.XH2O (in case of DETAPMPO). The electronic spectra have shown them to be six coordinated with slight distortion from octahedral geometry. Antiferromagnetism was inferred from magnetic moment data. Infrared spectral studies were carried out to determine coordination sites. EPR (Electron Paramagnetic Resonance) spectra that supports the presence of tetragonal distortion and antiferromagnetic behaviour, have also been studied.

EFFECTS OF COPPER DOPING ON DIELECTRIC AND A.C. CONDUCTIVITY IN LAYERED SODIUM TRI-TITANATE CERAMIC

2013 ◽  
Vol 27 (22) ◽  
pp. 1350114 ◽  
Author(s):  
SHRIPAL ◽  
SHAILJA DWIVEDI ◽  
RAKESH SINGH ◽  
R. P. TANDON
Keyword(s):  
Ionic Conduction ◽  
Relaxation Times ◽  
Paramagnetic Resonance ◽  
Temperature Range ◽  
Higher Temperature ◽  
Polaron Conduction ◽  
Tan Δ ◽  
Lower Temperature ◽  
Electron Paramagnetic ◽  
Derivatives Of

Electron paramagnetic resonance (EPR) spectra of 0.01, 0.1 and 1.0 molar percentage (mp) of CuO doped derivatives of layered Na 2 Ti 3 O 7 ceramic have been reported. The results show that copper substitutes as Cu 2+ at Ti 4+ octahedral sites. From the dependence of loss tangent ( tan δ) and the relative permittivity (ε′) on temperature and frequency, it is concluded that all the derivatives are of polar nature. The relaxation peaks at lower temperatures have been attributed to the presence of different types of dipoles, whereas peaks in the higher temperature region indicate possible ferroelectric phase transition. The dependence of conductivity on temperature show that electron hopping (polaron) conduction exists in a wide span of temperature range. However, the associated interlayer ionic conduction exists in a small temperature range. Interlayer alkali ion hopping mechanism of conduction has been proposed toward higher temperatures. The conductivity versus frequency plots reveal that the polaron conduction plays a prominent role toward the lower temperature side that diminishes with the rise in temperature. The most probable relaxation times for 0.01 and 0.1 mp CuO doped derivatives are almost same but it records an increased value for 1.0 mp doped material. This again attributes to the possible change in the symmetry of copper environment.

scholarly journals Radical Formation in Sugar-Derived Acetals under Solvent-Free Conditions

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5897
Author(s):  
Aleksandra A. Wróblewska ◽  
H. Y. Vincent Ching ◽  
Jurrie Noordijk ◽  
Stefaan M. A. De Wildeman ◽  
Katrien V. Bernaerts
Keyword(s):  
Hydrogen Abstraction ◽  
Solvent Free ◽  
Paramagnetic Resonance ◽  
Cyclic Acetals ◽  
Radical Degradation ◽  
Solvent Free Conditions ◽  
Amide Exchange ◽  
Methylene Unit ◽  
Electron Paramagnetic ◽  
Derivatives Of

The degradation of acetal derivatives of the diethylester of galactarate (GalX) was investigated by electron paramagnetic resonance (EPR) spectroscopy in the context of solvent-free, high-temperature reactions like polycondensations. It was demonstrated that less substituted cyclic acetals are prone to undergo radical degradation at higher temperatures as a result of hydrogen abstraction. The EPR observations were supported by the synthesis of GalX based polyamides via ester-amide exchange-type polycondensations in solvent-free conditions at high temperatures in the presence and in the absence of radical inhibitors. The radical degradation can be offset by the addition of a radical inhibitor. The radical is probably formed on the methylene unit between the oxygen atoms and subsequently undergoes a rearrangement.

scholarly journals Electron paramagnetic resonance, optical absorption and Raman spectral studies on a pyrite/chalcopyrite mineral

2012 ◽  
Vol 96 ◽  
pp. 310-315 ◽  
Author(s):  
G. Udayabhaskar Reddy ◽  
K. Seshamaheswaramma ◽  
Yoshinobu Nakamura ◽  
S. Lakshmi Reddy ◽  
Ray L. Frost ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Optical Absorption ◽  
Spectral Studies ◽  
Paramagnetic Resonance ◽  
Electron Paramagnetic ◽  
Raman Spectral

scholarly journals Complexes With Biologically Active Ligands. Part 2. Preparation of Copper(II) Complexes of Positively-Charged Derivatives of Aminoglutethimide

1996 ◽  
Vol 3 (2) ◽  
pp. 57-62 ◽  
Author(s):  
Claudiu T. Supuran
Keyword(s):  
Octahedral Geometry ◽  
Organic Ligands ◽  
Biologically Active ◽  
Water Molecules ◽  
Donor Atom ◽  
Alkyl Aryl ◽  
Coordination Sites ◽  
Zinc Enzyme ◽  
Derivatives Of ◽  
Positively Charged

Cu(II) complexes of 1-[4-(3-ethyl-piperidine-2,6-dione)-3-yl]-phenyl-2,4,6-trisubstituted pyridinium perchlorates, containing alkyl, aryl and combinations of these two types of moieties in their molecule were synthesized and characterized by elemental analysis, spectroscopy, magnetic, thermogravimetric and conductimetric measurements. In these complexes, Cu(II) ions are in octahedral geometry with four water molecules occupying the equatorial coordination sites and the two organic ligands in deprotonated state the remaining axial ones. The donor atom of these ligands is constituted by the ionized nitrogen of the glutarimide moiety. The new derivatives possess weak inhibitory activity towards the zinc enzyme carbonic anhydrase.

scholarly journals Transition metal M(II) complexes with isonicotinoylhydrazone-9-anthraldehyde

2010 ◽  
Vol 75 (11) ◽  
pp. 1515-1531 ◽  
Author(s):  
M.L. Dianu ◽  
A. Kriza ◽  
N. Stanica ◽  
A.M. Musuc
Keyword(s):  
Thermal Analyses ◽  
Thermal Studies ◽  
Octahedral Geometry ◽  
Spectral Studies ◽  
Conductivity Measurements ◽  
Tetrahedral Geometry ◽  
Physico Chemical ◽  
Pyridine Nitrogen ◽  
Infrared Spectral ◽  
Nitrate Complexes

New complexes of isonicotinoylhydrazone-9-anthraldehyde with Cu(II), Co(II) and Ni(II) have been prepared and characterized by analytical and physico-chemical techniques, such as elemental and thermal analyses, magnetic susceptibility and conductivity measurements, and electronic, EPR and IR spectral studies. The infrared spectral studies revealed the bidentate or monodentate nature of the Schiff base in the complexes; the pyridine nitrogen does not participate in the coordination. A tetrahedral geometry is suggested for the nitrate-complexes and an octahedral geometry for the others. Thermal studies support the chemical formulation of these complexes.

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