Proceedings of the Indian Academy of Sciences - Chemical Sciences

Nair, M.; Nagarajan, K.; Desai, J.; Kulkarni, Y.; Shah, R.

doi: 10.1007/BF02863250pmid: N/A

Addition of 1,8-diaminonaphthalene1 to dimethylacetylene dicarboxylate (DMAD) leads to the perimidine4a and the naphthodiazepine3a. A similar reaction with the diethyl ester (DEAD) gave rise to3b and4b. The latter product has been incorrectly formulated as naphthodiazepine2b in the literature. 1,8-Dihydroxynaphthalene8 and DMAD gives rise to the naphthodioxane9, which is hydrolysed to the diacid11. 8-Hydroxy-1,2,3,4-tetrahydroquinoline (14) and acetylenic esters form pyridobenzoxazines15, which exist as equilibrium mixture of15 and16 in solution. The ethyl ester is hydrogenated to the dihydroderivative18b.1H and more particularly13C NMR spectra are used to assign structures to various products.

Bhat, G.

doi: 10.1007/BF02863254pmid: N/A

The study of electrochemical reduction of Cu(II)-EDTA system by phase sensitive a.c. impedance method at dropping mercury electrode reveals several interesting features. The complex plane polarograms exhibit loop like shape in contrast to the classical zinc ion reduction where crest like shape is found. Again, the relative placement of peaks of in-phase and quadrature components, and the relative placement of portions before and after the peaks of complex plane polarograms are different from that of zinc ion reduction. The complex plane plots suggest that electrochemical reduction of Cu-EDTA is charge transfer controlled.

Narasimham, P.; Mahadevan, Sudha; Rao, K.

doi: 10.1007/BF02863251pmid: N/A

The d.c. conductivities of K2SO4-ZnSO4 glasses have been measured over a wide range of temperature. It has been found that two different subglassy activation energies are present which may be associated with K+ and Zn++ ions. Also a conductivity maximum occurs as a function of composition. These features have been discussed in the light of the random close packed model of sulphate glasses.

Mallik, Biswanath; Ghosh, Alpana; Misra, T.

doi: 10.1007/BF02863253pmid: N/A

The change in semiconductive properties of vitamin A (alcohol and acetate) after adsorption of various vapours on its crystallite surface has been studied at a constant sample temperature. A rapid enhancement in the semi-conductivity has been observed. The rise in conductivity has been found to be exponential with increasing vapour pressure of the adsorbed gas. It has been suggested that charge transfer (CT) interaction may be responsible for such conductivity change. The adsorption process being efficiently reversible this CT complex is weakly bound.

D’sa, J.; Patel, K.; Patel, R.

doi: 10.1007/BF02863258pmid: N/A

A poly (Schiff base) has been prepared by the condensation of 4,4′-dihydroxy-3, 3′-diacetyl-biphenyl and benzidine. Cu(II), Ni(II) and Co(II) coordination polymers of PSB have been synthesised. The magnetic moment and the electrical resistivity have been reported.

Subba Rao, S.; Gopalakrishnan, R.

doi: 10.1007/BF02863255pmid: N/A

Magnetic susceptibilities, ultrasonic velocities, refractive indices and dielectric constants of the mixtures, n-butyl alcohol in cyclohexane were determined as a function of concentration. Deviations from the normal behaviour were observed which may be attributed to the deassociation of hydrogen bonds and interstitial occupation of non-polar solvent molecules.

Pradhan, S.

doi: 10.1007/BF02863256pmid: N/A

The volume change on mixing (V E) of binary systems of methanol (1) +n-butylamine, isobutylamine, sec. butylamine and tert. butylamine (2) were determined at 25‡ C by density method. All the four systems showed a large negative volume change on mixing and the maxima were observed nearly at 0.5 mole fraction. This was attributed to the possibility of 1 : 1 type of complex formation between amine and methanol. TheV E was found to depend on the structure of butylamine and the magnitude ofV E increased as tert.-BuNH2 > sec.-BuNH2 > iso-BuNH2 >n-BuNH2 This particular trend is attributed to increase in the number of amine-alcohol species formed on the mixing and the geometric fitting of methanol in the liquid structure of the butylamine.

Palanna, O.

doi: 10.1007/BF02863252pmid: N/A

A new MgV2O6 phase having brannerite (ThTiO6) related structure is obtained by solid state reaction and its x-ray powder diffraction and thermal studies are discussed. These studies confirm a structural transition at 833 K for non-stoichiometric magnesium metavanadate. The phase transition is reversible and the two forms of MgV2O6 have a closely related crystal structure.