Solvent effect on electronic absorption spectra of some chlorophenols: Part II - Application of Bakhshiev's theoretical model for elucidating excited state dipole moments and specific solute-solvent interaction energies

215-219A systematic and simple procedure employing Bakhshiev's expression for solvatochromic frequency shifts in electronic absorption spectra for estimating the excited state dipole moments and specific solute-solvent interaction energies is developed. The results for several chlorophenols based on this method are found to be in close agreement with those obtained by applying the more commonly used McRae's expression-for solvent-induced frequency shifts. The method described herein can be employed as an alternative approach for studying solute-solvent interactions

Solvent effects on electronic absorption spectra of some chlorophenols: Part I - Excited state dipole moments and specific solute-solvent interaction energies based on McRae's theory

845-853On the basis of McRae's theory [J phys Chem, 58 (1954) 1002] of solvent effect on electronic spectra, a systematic and step-wise procedure for estimating the excited state dipole moments (Il,) of various chlorophenols and their specific interaction energies (Es) with different types of solvents is described. The μe’s estimated by employing only saturated hydrocarbon sovlents are found to be more reliable than those estimated using pairs of polar solvents such as acetonitrile and diethyl ether. The Es values are found to decrease with increase in the number of CI atoms in the solute molecules. Interaction energies of water are generally the largest and those of carbon tetrachloride and diethyl ether are usually negligibly small. The specific interactions in the present solute-solvent systems are electrostatic in nature

Thermogravimetric and differential thermal analysis of bipyridyl, <i style="mso-bidi-font-style: normal">ortho</i>-phenylenediamine and 1,10 phenanthroline complexes of some Cu(II) salts

299-302Dynamic TGA and DTA studies on thermal decomposition of coordination complexes of bipyridyl, ortho-phenylenediamine and 1.10 phenanthroline with Cu(II) chloride, nitrate, sulphate. acetate and oxalate reveal that the process occurs through the stages: liquefaction, dehydration, deamination, deanionation and oxidation of Cu. All the steps are composite in nature consisting of simultaneous loss of the component moieties in varying proportions and the related ∆Hs and Eas are significantly dependent on the nature of the co-anions and ligands. </span

Spin dynamics in 1-D mixed valence complex [Pt(En)₂][PtCl₂][ (en) ₂][](C1O₄][)₄][ studied by proton magnetic resonance

1H NMR spin-lattice relaxation time T1 of the above complex in the solid state was measured from 100 K to room temperature. The presence of paramagnetic PtIII sites trapped in the 1-D chains was observed at low temperatures. T1 was shortened upon heating, and the observed T1 data were well explained by the model that the trapped unpaired electrons are thermally excited and diffuse along the chain. The observed spin motion is attributable to the neutral soliton by referring to the data of ESR and the electrical conductivity

Trimethylamine sensing properties of thorium-incorporated tin oxide

We report the trimethylamine (TMA) sensing properties of thoria-incorporated tin oxide. The tin oxide pellet having 3 wt.% of thoria exhibits a high sensitivity of 1500 towards 800 ppm of TMA compared to only 18 of pure tin oxide at a lower operating temperature of 225 °C. The incorporation of thorium in tin oxide enhances the sensitivity towards TMA with improved selectivity. The effect of surface coverage, morphology and oxidation state on the sensitivity has been studied using techniques like scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The correlation between thoria incorporation in the tin oxide at different sintering temperatures and the improvement in the selectivity and sensitivity towards TMA is discussed