http://nopr.niscpr.res.in/handle/123456789/40557 Tue, 06 Oct 2026 12:44:46 GMT 2026-10-06T12:44:46Z http://nopr.niscpr.res.in/handle/123456789/40663 Title: Low temperature synthesis and interconversions of copper sulphides using acetonitrile Authors: Kalyanaraman, P; Vijayashree, N; Samuelson, A G Abstract: Low temperature preparation of crystalline covellite. chalcocite and digenite from the constituent elements is promoted by acetonitrile. Interconversion of digenite and chalcocite is also possible by addition of the appropriate constituent element in acetonitrile. Factors which determine the .phase of the copper chalcogenide formed have been elucidated. Evidence is presented for the involvement of molecular intermediates in their formation. Page(s): 281-283 Fri, 01 Apr 1994 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/40663 1994-04-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/40662 Title: Electrochemical studies on bis(pentahaptocyclopentadienyl)iron encapsulated in aqueous Triton X-IOOmicelles Authors: Mahanta, Nivedita; Medhi, Okhil K Abstract: Electrochemical studies on bis(pentahaptocyclopentadienyl)iron (ferrocene) have been carried out in aqueous solutions of Triton X-100 micelles. The ferrocene/ferricinium couple isreversible with the E^o’ value at + 0.216 ± 0.006V depending on various conditions of added electrolyte and ionic strength of the media. Compared to the values in nonaqueous media, the E^o’ value shows cathodic shift of ~ 260 mV.The diffusion coefficient (D_o) values of ferrocene in micelles (0.5-1.2 x 10^-6cm²sec^-1) are much smaller than those in nonaqueous media (e.g. in DMF D_o is 11.2 x 10 cm²sec^-1). The heterogeneous electron transfer rate constants (k) are found to be in the range 7.9-12.5 x 10^-3 cm sec^-1 in the surfactant solution. Page(s): 284-286 Fri, 01 Apr 1994 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/40662 1994-04-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/40661 Title: Thermodynamics and topological investigations of molecular interactions in methylene bromide + nitrobenzene mixture Authors: Sharma, V K; Singh, P P; Maken, S; Singh, Bhup Abstract: Molar excess volumes, <i>V</i>^E, and molar excess enthalpies, <i>H</i>^E for methylene bromide(i) + nitrobenzene(j) mixture have been measured as a function of composition at 308.15 K. Graph-theoretical analysis of <i>V</i>^E data suggests that while nitrobenzene exists as equilibrium mixture of monomer and dimer in this mixture, the mixture as such contains a 1:1 molecular complex. IR and NMR studies lend further credance to this viewpoint. Page(s): 287-290 Fri, 01 Apr 1994 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/40661 1994-04-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/40660 Title: Solvent and electrode kinetic effects on the anodic oxidation of Br^- in water and some dipolar aprotic solvents on bare and platinized Pt and C surfaces ^† Authors: Datta, Jayati; Sinha, Subrata; Kundu, Kiron K Abstract: The solvent effects on the exchange current densities (i_o)for anodic oxidation of Br^- on platinum (Pt),-graphite (C) and their platinized surfaces, (Pt)Pt or (C)Pt at 15, 25 and 35°C have been determined in water as well as in some pure non-aqueous solvents like acetonitrile (ACN), N,N-dimethylformamide (DMF) and propylene carbonate (PC) by potentiostatic polarization technique under near equilibrium condition. For all the electrodes except C, the observed order of io values in different organic solvents followed the sequence: ACN> DMF> PC and that on C electrode: ACN > PC > DMF. On the other hand, for any solvent except water, the observed io values on different electrodes are in the order: (C)Pt≥(Pt)Pt>Pt>C and that in water: (Pt)Pt>Pt≥(C)Pt>C.. The kinetic solvent effect (KSE) data at 25°C relative to that in water have been analyzed in the light of relative stabilization of the initial state (Br^-] and the transition state (TS), as well as the extent of free surface (1 - <i><i><img src='/image/spc_char/theta.gif' border=0></i></i>_s,), the coverage, <img src='/image/spc_char/theta.gif' border=0>_sbeing guided by image interactions' inducted by dipolar and dispersion interactions of the cosolvents with the surfaces. The observed virtual heats of activation at the reversible potentia. (<img src='/image/spc_char/delta.gif' border=0><i>H</i>^{0 <i>#</i>}) which ref1ectintrinsic electrocatalytic activities of the electrodes, being of the order C≥ Pt > (Pt)Pt > > (C)Pt, suggest that graphite (C) electrode is intrinsically a weaker electrocatalyst than both the (C) Pt and (Pt)pt or even bare Pt electrode and that the superiority of (C)Pt over (Pt)Pt is seemingly due to the porous nature of C substrate. Page(s): 291-296 Fri, 01 Apr 1994 00:00:00 GMT http://nopr.niscpr.res.in/handle/123456789/40660 1994-04-01T00:00:00Z