NOPR Collection:

Determination of inductive effect parameter of methyl group from gas-phase charge transfer bands of molecular complexes of N-phenyl-tetrachlorophthalimide with methyl substituted benzenes

1989-08-01T00:00:00Z

Title: Determination of inductive effect parameter of methyl group from gas-phase charge transfer bands of molecular complexes of N-phenyl-tetrachlorophthalimide with methyl substituted benzenes Authors: Roy, M; Mukherjee, A K; Seal, B K Abstract: The charge transfer absorption bands of electron donor-acceptor (EDA) complexes of N-phenyltetrachlorophthalimide as acceptor with a series of methyl substituted benzenes as donors have been studied in dioxan, chloroform, dichloromethane and dimethylformamide as solvents. The absorption maxima (v_CT) of the complexes in these solvents deviate greatly from Mulliken's equation when plotted against donor ionisation potentials but the gas-phase values of v_CT, determined from the CT transition energies in the first three weakly polar solvents, give a reasonable fit to Mulliken type plot with the donor ionisation potentials. The energies of the HOMOs of methyl substituted benzenes, obtained as functions of the inductive effect PMO parameter (h_Me) of the methyl group by Coulson-Longuet- Higgins perturbation technique, give a linear correlation with the gas-phase hv_CT values of the complexes. From the slope of this plot, h_Me is found to be -0.1843, a value in fair agreement with that (-0.21) obtained by Lepley from studies of CT complexes of TCNE with a series of methyl substituted benzenes and naphthalenes. Page(s): 635-638

Charge-transfer complexation reaction in the solid state - reaction between p-chloranil and 8-hydroxyquinoline

1989-08-01T00:00:00Z

Title: Charge-transfer complexation reaction in the solid state - reaction between p-chloranil and 8-hydroxyquinoline Authors: Singh, N B; Singh, R J; Singh, N N Abstract: p-Chloranil forms 1:2 charge transfer complex with 8-hydroxyquinoline both in solid state and solution. It is found that during solid state reaction, 8-hydroxyquinoline diffuses towards p-chloranil. The diffusion is a vapour phase dominated process although surface migration also occurs. Initial reaction starts at the point of defect present in the crystal lattice of p-chloranil. Page(s): 639-644

Thermal reactions of CdC12 and CdBr2 in NaNO3-KNO3 eutectic melt

1989-08-01T00:00:00Z

Title: Thermal reactions of CdC12 and CdBr2 in NaNO3-KNO3 eutectic melt Authors: Singh, N B; Kumar, P; Pandey, S P Abstract: CdCl₂ and CdBr₂, dissolve in NaNO₃-KNO₃ eutectic melt. When these melts are heated, cadmium halides undergo decomposition reaction, CdBr₂ reacting with a faster rate as compared with CdCl₂. The two reactions obey second order kinetics. In the case of CdCl₂, eutectic system, CdO, NaCl, KCl, NO₂ and O₂, are obtained as the end products. However, in the case of CdBr₂-eutectic system, CdO, NaBr, KBr, Br, NO₂ and O₂ are obtained as the reaction products. The kinetics of the reactions have been followed by isothermal thermogravimetry and the solid residues identified by X-ray diffraction technique. The gaseous products have been analysed in the usual manner. Mechanisms of reactions have been explored by DTA technique also. Page(s): 645-648

Thermal stability of doped γ-ferric oxide

1989-08-01T00:00:00Z

Title: Thermal stability of doped γ-ferric oxide Authors: Bhat, Ramachandra; Anantharaman, M R; Keer, H V Abstract: The thermal stablity of γ-ferric oxide doped with magnesium (II), cobalt (II), nickel (II) and copper (has been studied. The dopant cations get substituted in the γ-ferric oxide lattice. The Madelung constant and the Coulomb energy have also been evaluated. The dopants such as magnesium (II), cobalt (II), nickel (II) and copper (II) stabilize the γ-Fe₂O₃ lattice, as revealed by the increase in the temperature of onset of the phase transition (conversion into ɑ- Fe₂O₃) as compared to that of pure maghemite. Page(s): 649-652