NOPR Collection:

Luminol fluorescence quenching by triethyl amine and non-linear Stern-Volmer plot : Solvent effect

2016-07-20T05:50:29Z

Title: Luminol fluorescence quenching by triethyl amine and non-linear Stern-Volmer plot : Solvent effect Authors: Guha, D; Mitra, S; Das, R; Mukherjee, S Abstract: The interaction of 3-aminophthalhydrazide (luminol) with a quencher, triethyl amine (TEA) has been studied employing steady-state and nanosecond time resolved emission spectroscopy. The bimolecular rate constant for fluorescence quenching in water is found to be about two orders of magnitude higher than that obtained in 1,4- dioxane (DIO).The Stern-Volmer (S-V) plot for fluorescence quenching exhibits positive deviation from linearity when water is used as solvent. On the other hand, the S-V plot shows negative deviation from linearity when DIO is used as a solvent. The rate constants obtained in ethanol, dimethyl sulphoxide (DMSO) and DIO are found to be similar to the rate constant for diffusional process. The possible interpretation of the quenching mechanism and nature of deviation from S-V plots have been discussed in relation to the strength of interaction between the colliding species. It is shown that the rate of luminol fluorescence quenching is dependent on the nature of the solvent, being particularly fast in aqueous medium. Page(s): 760-767

Topological QSAR studies on antifungal benzoxazoles

2013-01-27T16:33:26Z

Title: Topological QSAR studies on antifungal benzoxazoles Authors: Soni, Sunil K; Agrawal, Vijay K; Khadikar, P V; Srivastava, A K Abstract: Antifungal activities of a series of benzoxazoles have been investigated by topological Quantitative Structure-Activity Relationship (QSAR) analyses. Use of molecular negentropy (N) as well as first order valence connectivity (¹χ^V) indices introduced by Kier has been made for this purpose. Excellent results have been obtained by introducing hydrophobic, electronic, steric and structural parameters in addition to these topological indices. Page(s): 745-752

Synthesis and characterization of oxovanadium(IV), chromium(III), manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of a new neutral ambidentate nitrogen donor

2013-01-26T16:34:14Z

Title: Synthesis and characterization of oxovanadium(IV), chromium(III), manganese(II), iron(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of a new neutral ambidentate nitrogen donor Authors: Rani, D Sandhya; Ananthalakshmi, P V; Jayatyagaraju, V Abstract: A few complexes of VO(II), Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2,3-dihydrazino quinoxaline(DHQ) have been synthesized and characterized by analytical, conductance, thermal, spectral and magnetic data. All the complexes are non-electrolytes. The ligand behaves as bis-NN donor in all the complexes, coordinating through the ring azomethine nitrogen and nitrogen of terminal NH₂. The ESR spectrum of VO(II) complex shows higher 'g' value(2.023G). Page(s): 843-846

Kinetics and mechanism of oxidation of ascorbic acid by cobalt (III) amino polycarboxylato complexes in weakly basic media

2016-07-20T05:41:12Z

Title: Kinetics and mechanism of oxidation of ascorbic acid by cobalt (III) amino polycarboxylato complexes in weakly basic media Authors: Makote, Rajendra D; Chatterjee, Chinmay Abstract: The kinetics of outer-sphere oxidation of L-ascorbic acid ((H₂A) by Co(nta)(gly), Co(nta)(ox)² and Co(nta)(pic) complexes have been investigated in weakly basic aqueous media (pH = 7.6 to 9.6) at 30-46° C. The pseudo-first order rate constant, k_obs shows first order dependence on ascorbic acid concentration, and increases rapidly with decrease in hydrogen ion concentration. The experimental data fits the rate law... Page(s): 783-791