NISCAIR Online Periodicals Repository Collection: IJC-A Vol.48A(04) [April 2009]

Single ion transfer entropies in binary mixtures of isodielectric protic ethylene glycol and dipolar aprotic N, N-dimethylformamide vis-à-vis 3D-structuredness of aqueous co-solvents

Sun, 29 Mar 2009 22:58:59 GMT

Title: Single ion transfer entropies in binary mixtures of isodielectric protic ethylene glycol and dipolar aprotic N, N-dimethylformamide vis-à-vis 3D-structuredness of aqueous co-solvents

Authors: Dolui, B K; Bhattacharya, S K; Kundu, K K

Abstract: Single ion transfer entropies, ∆S⁰_t(i) of some electrolytes like tetraphenylarsonium picrate, potassium tetraphenylborate, potassium picrate and potassium chloride from protic ethylene glycol to its isodielectric mixtures with 20, 40 and 60 wt % protophilic dipolar aprotic N,N-dimethylformamide have been determined at 25 °C using the Ph₄AsPh₄B TATB reference electrolyte assumption, and solubility of the salts measured at 15°, 20°, 30° and 35°C, and that at 25 °C reported earlier. ∆S⁰_t(i) of the ions as well as their chemical effects, ∆S⁰_t,_ch(i) (as obtained after correcting for the cavity effects, ∆S⁰_t,_cav(i) and ignoring Born-type electrostatic effect ∆S⁰_t,_Born(i), since the solvent mixtures are isodielectric), exhibit mirror-image behaviour of simple cation like K⁺ and anion like Cl^-, which can be explained in the light of Kundu et al.’s four step transfer process. However, this feature in completely non-aqueous solvent system is strikingly different from that in aquo-cosolvent systems studied earlier, and offers an indirect evidence that the ‘characteristic mirror-image relationship’ of simple cations and anions, in aqueous cosolvent systems, is, as contended earlier, associated with 3D-‘structuredness’ of aqueous cosolvent systems. This reiterates that T∆S⁰_{t, ch}(i) serves as a useful probe for the 3D-structuredness of aqueous cosolvents.

Page(s): 504-511

Synthesis, crystal structures and protease activity of amino acid Schiff base iron(III) complexes

Sun, 29 Mar 2009 22:58:59 GMT

Title: Synthesis, crystal structures and protease activity of amino acid Schiff base iron(III) complexes

Authors: Begum, Mohammed S Ameerunisha; Nethaji, Sounik Saha, Munirathinam; Chakravarty, Akhil R

Abstract: Iron(III) complexes, (NHEt₃)[Fe(III)(sal-met)₂] and (NHEt₃)[Fe(III)(sal-phe)₂], of amino acid Schiff base ligands, viz., N-salicylidene-L-methionine and N-salicylidene-L-phenylalanine, have been prepared and their binding to bovine serum albumin (BSA) and photo-induced BSA cleavage activity have been investigated. The complexes are structurally characterized by single crystal X-ray crystallography. The crystal structures of the discrete mononuclear monoanionic complexes show FeN₂O₄ octahedral coordination geometry in which the tridentate dianionic amino acid Schiff base ligand binds through phenolate and carboxylate oxygen and imine nitrogen atoms. The imine nitrogen atoms are trans to each other. The Fe-O and Fe-N bond distances range between 1.9 and 2.1 Å. The sal-met complex has two pendant thiomethyl groups. The high-spin iron(III) complexes (μ_eff ~ 5.9 μ_B) exhibit quasi-reversible Fe(III)/Fe(II) redox process near -0.6 V vs. SCE in water. These complexes display a visible electronic band near 480 nm in tris-HCl buffer assignable to the phenolate-to-iron(III) charge transfer transition. The water soluble complexes bind to BSA giving binding constant values of ~10⁵ M^-1. The complexes show non-specific oxidative cleavage of BSA protein on photo-irradiation with UV-A light of 365 nm.

Page(s): 473-479

Thermodynamic and transport properties of binary liquid mixtures of sulfolane with some lactones at 308.15 K

Sun, 29 Mar 2009 22:58:59 GMT

Title: Thermodynamic and transport properties of binary liquid mixtures of sulfolane with some lactones at 308.15 K

Authors: Patwari, Murali Krishna; Bachu, Ranjith Kumar; Boodida, Sathyanarayana; Nallani, Satyanarayana

Abstract: The values of density, viscosity and speed of sound have been measured for binary liquid mixtures of γ-butyrolactone, δ-valerolactone and ε-caprolactone with sulfolane over the entire composition range at T =308.15 K and atmospheric pressure. From this data, excess molar volume, deviation in viscosity and deviation in isentropic compressibility have been calculated. The results are fitted to a Redlich-Kister type polynomial equation to derive binary coefficients and standard deviations. The results are interpreted in terms of molecular interactions between the unlike molecules.

Page(s): 526-530

Synthesis and chelation ion exchange properties of 2, 4-dihydroxyacetophenone-biuret-formaldehyde terpolymer resin

Sun, 29 Mar 2009 22:58:59 GMT

Title: Synthesis and chelation ion exchange properties of 2, 4-dihydroxyacetophenone-biuret-formaldehyde terpolymer resin

Authors: Rahangdale, S S; Gurnule, W B; Zade, A B

Abstract: The terpolymer resin 2, 4-dihydroxyacetophenone-biuret-formaldehyde has been synthesized by the condensation of 2, 4-dihydroxyacetophenone and biuret with formaldehyde in 2:1:3 molar ratios in presence of 2M hydrochloric acid as catalyst. UV-visible, IR and proton NMR spectral studies have been carried out to elucidate the structure of the resin. The terpolymer has proved to be a selective chelating ion exchange polymer for some metals. Chelating ion exchange properties of this polymer have been studied for Fe³⁺, Cu²⁺, Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺and Pb²⁺ ions. Batch equilibrium method has been employed to study the selectivity of metal ion uptake and distribution coefficient over a wide pH range and in media of varying ionic strengths. The polymer shows higher selectivity for Fe³⁺and Cu²⁺ ions than for Ni²⁺, Co²⁺, Zn²⁺, Cd²⁺ and Pb²⁺ ions. Study of distribution ratio as a function of pH indicates that the amount of metal ion uptake by resin increases with the increasing pH of the medium.

Page(s): 531-535