NOPR Collection:

Synthesis and characterization of copper (I) and copper (II) complexes with 1,5-bis (benzimidazol-2-yl)-3-thiapentane

1999-03-01T00:00:00Z

Title: Synthesis and characterization of copper (I) and copper (II) complexes with 1,5-bis (benzimidazol-2-yl)-3-thiapentane Authors: Nohria, Lata; Rajesh; Mathur, Pavan Abstract: Complexes with formula [Cu(BBES)X₂]_.nH₂O have been synthesized where BBES is a tridentate ligand containing bis-benzimidazolyl as pendant coordinating group and X is an exogenous anionic ligand (X = HCOO^- , CH₃COO^- ,Cl^-, Br^-, NO^-₃). Solution EPR spectroscopy on these complexes reveals that the ground state in these copper (II) complexes comprises ^d _x2-y2orbital. Cyclic voltammetric studies reveal that E_1/2for Cu(II)/Cu(I) couple shifts cathodically with HCOO^- as the anionic ligand, implying that binding of this anion stabilizes the Cu (II) state whereas E_1/2 , data for NCS^-indicates that this anion destabilizes Cu(II) state. Copper (I) complex has also been synthesised in the presence of hydroquinone which shows a well-resolved NMR spectrum in the range 0-10 ppm. Page(s): 256-261

Molar excess free energy of mixing of 1-propanol or 2-propanol + aromatic hydrocarbons at 308.15 K in terms of an association model with a Flory contribution term

1999-03-01T00:00:00Z

Title: Molar excess free energy of mixing of 1-propanol or 2-propanol + aromatic hydrocarbons at 308.15 K in terms of an association model with a Flory contribution term Authors: Maken, Sanjeev; Gupta, Vibha; Kalra, K C; Singh, K C Abstract: Excess molar Gibbs free energy of mixing for 1-propanol or 2-propanol + benzene, + toluene, + o-, m-and pxylenes at 308.15 K are calculated by Barker's method from vapour pressure data measured by a static method. The free energy of mixing for these binary systems are also predicted in terms of Mecke-Kempter type of association model with Flory contribution term using two interaction parameters. The predicted value agrees reasonably well with the experimental values. Page(s): 219-229

Excess molar volumes and excess partial molar volumes of diethylene glycol monoethyl ether - n-alcohol mixtures at 298.15 K

1999-03-01T00:00:00Z

Title: Excess molar volumes and excess partial molar volumes of diethylene glycol monoethyl ether - n-alcohol mixtures at 298.15 K Authors: Pal, Arnalendu; Dass, Gurcharan Abstract: Excess molar volumes V_m^E have been measured for binary mixtures of diethylene glycol monoethyl ether with methanol, ethanol, 1- propanol, 1-pentanol and 1-hexanol as a function of composition using a continuous-dilution dilatometer at 298.15 K. The excess molar volumes V_m^E are negative over the entire range of composition for the systems diethylene glycol monoethyl ether + methanol, + ethanol , and + 1-propanol and positive for the remaining systems, diethylene glycol monoethyl ether + 1-pentanol, and + 1-hexanol. The measured V_m^E values increase towards positive direction with increase in chain length of the n-alcohol. The V_m^E results have been used to estimate the excess partial molar volumes V_m^E ._iof the components and have also been analysed using the Prigogine - Flory – Patterson (PFP) theory. An analysis of each of the three contributions viz. interactional, free volume and internal pressure to V_m^E shows that the free volume effect and internal pressure contribution are negative for all the mixtures, whereas the interactional contribution is negative for methanol and positive for remaining systems. The behaviour of V_m^E , V_m^E ._i and ₁₂ (Flory's interaction parameter) with composition and the number of carbon atoms in the alcohol molecule is discussed. Page(s): 237-243

A correlation of the thickness of the nitrocellulose films prepared using a spinning disk technique with the observable properties of nitrocellulose solution

1999-03-01T00:00:00Z

Title: A correlation of the thickness of the nitrocellulose films prepared using a spinning disk technique with the observable properties of nitrocellulose solution Authors: Nadkarni, Vishnu S.; Bhagwat, Sunil S.; Samant, Shriniwas D. Abstract: Spin coating method has been successfully used to cast CN-polyester composite films. Data have been presented after a systematic study of the nitrocellulose film format ion by this technique by using various types of solvents. The method can be extended to prepare CN-polyester composite solid state nuclear track detector films useful for environmental dosimetry. Page(s): 209-218