Spectral, Magnetic and Thermogravimetric Studies of Some Dimeric Oxovanadium(IV) Complexes

1986 ◽  
Vol 41 (11) ◽  
pp. 1443-1446
Author(s):  
P. K. Nath ◽  
N. C. Mishra ◽  
V. Chakravortty ◽  
K. C. Dash
Keyword(s):  
Thermal Decomposition ◽  
Schiff Base ◽  
Ir Spectra ◽  
Magnetic Moment ◽  
Epr Spectroscopy ◽  
Anthranilic Acid ◽  
Room Temperature ◽  
Thermogravimetric Studies ◽  
Epr Signal ◽  
The Stability

Abstract The tridentate dibasic Schiff base anthranilic acid salicylideneimine (H2SB) reacts with VOCl2 in the presence o f NaOAc and imidazole (or its derivatives) to form dimeric oxovanadium (IV) complexes of the type [VO(S B)(D)]2. These green or yellow -green compounds have a magnetic moment of 1.4 B.M . at room temperature, and are non-electrolytes in MeOH . The compounds are characterised on the basis of electronic and IR spectra as well as EPR spectroscopy. The IR spectra shows a strong band due to v(V = O) at 880 cm-1 in addition to the bands of H2SB and imidazole. [VO(SB)(Im)]2 shows a single unresolved EPR signal at g = 1.9715 whereas compounds containing other imidazole derivatives show both a broadening and shifting of the signal. The thermogravimetric measurements indicate the stability of the complexes and their stepwise thermal decomposition.

Circular dichroism and infrared study of β-turn formation in repeat peptides of elastin

1987 ◽  
Vol 52 (5) ◽  
pp. 1356-1361
Author(s):  
S. Abdel Rahman ◽  
M. Elsafty ◽  
A. Hattaba
Keyword(s):  
Circular Dichroism ◽  
Solid State ◽  
Ir Spectra ◽  
Chain Length ◽  
Room Temperature ◽  
Infrared Study ◽  
Feature Characteristic ◽  
C 50 ◽  
The Stability ◽  
Circular Dichroïsm

The conformation of elastin-like peptides Boc-Ala-Pro-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM, Boc-Ala-Pro-Gly-Val-Gly-Val-Ala-Pro-Gly-Val-Gly-Val-APEGM were examined in solution using circular dichroism at 30 °C, 50 °C, and 70 °C and in solid state by IR at room temperature. The studies show that the β-turn is a significant conformational feature for peptides under investigation in solution at 30 °C and 50 °C, but at 70 °C the tetra, hexa, and decapeptides show the CD feature characteristic of the β-structure while the dodecapeptide spectra show the presence of β-turn which indicates the stability of the β-turn at this chain length. The IR spectra show that in the solid state at room temperature all investigated peptides assume essentially a β-turn except the tetrapeptide which present evidence of antiparallel β-structure. The β-turn contribution in the IR spectra increases with the increase of the chain length of the peptide.

scholarly journals Synthesis, Spectral Characterization and Pharmacological Significance of Cr(III) and Mn(II) Complexes with Schiff Base and Thiocyanate Ion as Ligands

2019 ◽  
Vol 11 (05) ◽  
Author(s):  
R. Govindharaju ◽  
P. Durairaj ◽  
T. Maruthavanan ◽  
M. Marlin Risana ◽  
T. Ramachandramoorthy
Keyword(s):  
Schiff Base ◽  
Free Radical ◽  
Ir Spectra ◽  
Metal Complexes ◽  
Magnetic Moment ◽  
Electronic Spectra ◽  
Metal Ion ◽  
Diffusion Method ◽  
Thiocyanate Ion ◽  
Ft Ir

Cr(III) and Mn(II) metal complexes of Schiff base ligand derived from phenylacetylurea condensed with salicylaldehyde (SBPS) and thiocyanate(SCN-) ion were synthesized by using microwave irradiation. Microwave assisted synthesis gives high yield of the complexes within a very short time. The molecular formulae and the geometry of the complexes have been deduced from elemental analysis, metal estimation, electrical conductance, magnetic moment, electronic spectra, FT- IR, Far IR spectra, cyclic voltammetry, thermal analysis and powder-XRD techniques. The molar conductance values indicate that the complexes are non-electrolyte (1:0) type. FT-IR spectra show that Schiff base and thiocyanate ion are coordinated to the metal ion in a monodentate manner. The electronic spectra and the magnetic moment indicate the geometry of the complexes is found to be octahedral. The antimicrobial activities of ligands and their Cr(III) and Mn(II) complexes were studied against the microorganisms, viz., E. coli, Klebsiella Pneumonia, P. aeruginosa, S. aureus, Bacillus cereus, Aspergillus flavus, Aspergillus niger, Aspergillus oryzae, Aspergillus sojae and Candida albicans by agar well diffusion method. The complexes show moderate activity against the bacteria and enhanced activity against the fungi as compared to free SBPS ligand. The free radical scavenging activity of the complexes and the ligands has been determined by measuring their interaction with the stable free radical, DPPH. The complexes have larger antioxidant activity as compared to the ligand. DNA-binding properties have been studied by fluorescence-emissions method. The results suggest that the complexes strongly bind to DNA because of metal complexes are well-known to speed up the drug action and the ability of a therapeutic agent which can frequently be enhanced upon coordination with a metal ion.

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