• V B Kartha

      Articles written in Proceedings – Section A

    • Hydrogen bonding and solvolysis of alkyl sulphonate esters and related compounds

      V B Kartha R Norman Jones R E Robertson

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      Hydrogen bonding between alkyl sulphonyl compounds andp-chlorophenol in carbon tetrachloride solution has been investigated by infra-red spectrometry. Analysis of the intensity of the bonded O-H stretching absorption indicates that, under the conditions employed, only 1:1 complexes are formed in significant concentration. Equilibrium constants for the complex formation have been determined at 15, 25, 35 and 45° C., and the corresponding enthalpy values derived. The strengths of the hydrogen bonds have been estimated from the positions of the bonded O-H stretching bands, and these frequencies correlate with the normal electronic effect of substitution in aryl and alkyl groups attached to the sulphonyl group. The rate of solvolysis of the methyl sulphonates in water is shown to vary inversely as the strength of the hydrogen bond formed. The possible bearing of these observations on certain aspects of the detailed mechanism of solvolysis is discussed.

    • Infra-red spectral studies of CHF2-CHCl2 and CBrCl2-CBrCl2

      V B Kartha Santha B Kartha N A Narasimham

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      The infra-red spectra of two polyhalogenated ethanes, 1, 1-difluoro-2, 2-dichloro ethane and 1, 2-dibromo-1, 1, 2, 2-tetrachloro ethane were obtained in the region of 2·5–38 microns. The spectra of CHF2-CHCl2 were obtained in gas, liquid and solid states and also in solvents of widely varying dielectric constants.

      These spectral studies showed that the molecule exists in the form of two rotational isomers. The fundamental modes of the two isomers were identified on the basis of intensity changes from gas to liquid to solid and in solvents of different dielectric constants. The observed infra-red absorption bands have been assigned in terms of the fundamental absorption bands.

      Spectra of CBrCl2-CBrCl2 were obtained in the solid and vapour phase and in various solvents. These spectra showed that CBrCl2-CBrCl2 exists only in the trans form. The infra-red spectra, combined with Raman data available from literature was used for complete assignment of the observed absorption bands.

    • N.M.R. and I.R. studies of 1, 1, 1 trifluoroacetone in proton donor solvents

      C L Khetrapal M M Dhingra V B Kartha

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      Interactions of 1, 1, 1 trifluoroacetone with proton donor solvents of the type RH [where R=HO, CH3S, CH3CH2CH2CH2S, CH3O, (CH3)2N, (C2H5)2N] have been investigated using NMR and infra-red techniques. Evidence of the formation of addition products of the type CF3.C(OH)R.CH3 where OH group is hydrogen-bonded with the fluorine of the CF3 group has been obtained.

    • Infrared spectra of salicylaldehyde complexes of some alkali metals

      V B Kartha N D Patel

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      The alkali metal chelates of salicylaldehyde have been prepared and their infrared spectra obtained. The spectra indicate strong bonding between the metal and hydroxy oxygen and only weak co-ordination of the metal to the carbonyl oxygen. For the lithium complexes two M-O stretching frequencies have been observed at about 590 cm.−1 and 490 cm.−1 The infrared spectra of the complexes have also given indirect evidence towards assignment of the C-OH and aldehydic C-H stretching frequencies.

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