P G Puranik
Articles written in Proceedings – Section A
Volume 37 Issue 4 April 1953 pp 499-503
Volume 38 Issue 3 September 1953 pp 233-238
The 1197 cm.−1 line in benzaldehyde is attributed to the C-C linkage between the aldehyde and the phenyl groups. The admixture of methyl and ethyl alcohols does not affect the C-C and C=0 frequencies in benzaldehyde. Mixtures with phenol show the formation of hydrogen bond resulting in the weakening of the C=O link and a lowering of the relative frequency. This is accompanied by an increase of the C-C frequency in the group. This phenomenon is analogous to what has been observed when hydrogen bonds are formed between acetone and alcohol molecules.
Volume 42 Issue 6 December 1955 pp 326-330
The Raman spectra of methyl and ethyl benzoates, and ethyl cinnamates have been recorded in the liquid state at 42° C. Some new lines are reported. The lines at 1181, 1280 and 1724 cm.−1 in methyl benzoate, and 1172, 1278 and 1719 cm.−1 in ethyl benzoate are assigned to the group and 1205, 1270 and 1639 cm.−1 are assigned to the group in ethyl cinnamate.
Volume 45 Issue 1 January 1957 pp 51-57
Volume 52 Issue 3 September 1960 pp 135-142
The cis and
Volume 54 Issue 2 August 1961 pp 69-79
The infra-red spectra of primary and secondary amides have been recorded in solutions at various concentrations with particular reference to 3
The effect of donor solvents on the frequencies of the amino and carbonyl bands has been investigated. It is observed that C=O frequencies of these amides in donor solvents are either the same or slightly higher/than those of the same amides in solutions of chloroform, but the N–H stretching frequencies in the same donor solvents are less, the N–H deformation frequencies more, than the frequencies of the corresponding linkages in solutions of chloroform. These results are explained on the basis that the primary and the secondary amides dissociate in donor solvents and then the donor group of the solvents forms hydrogen bond with the amino group of the amide in the monomeric state. The C=O frequency of these amides in solutions of dioxane in the presence of phenol was studied and its diminution is accounted for as due to hydrogen bond formation. The Raman spectra of N-methyl formamide and dimethyl formamide and in various solvents have been recorded. Shifts observed in a number of Raman lines of these substances in mixtures are explained.
Volume 54 Issue 3 September 1961 pp 121-131
The infra-red spectra of 2-amino-methyl pyridines and amino-quinolines have been recorded in solutions at various concentrations. The N-H stretching frequencies have been assigned on the basis of the presence of intermolecular associations and primary amino group in these compounds. The bands in the region of 1600 cm.−1 have been studied in considerable detail and the N-H deformation frequencies of monomer and associated molecules have been assigned. In all the amines studied, an absorption band appears in solutions of chloroform in the region of 2950 cm.−1 which is not present in the spectra of pure amines or in solutions of carbon tetrachloride. The presence of this band has been explained as due to the associations between the free N-atom of the monomer amines and the H-atom of the chloroform.
Volume 54 Issue 3 September 1961 pp 146-154
The Raman and infra-red spectra of toluidines and
Volume 56 Issue 2 August 1962 pp 96-102
The shift in the N-H stretching frequency in the infra-red spectra of amides, due to intermolecular associations, calculated on the basis that the hydrogen bonding is essentially an electrostatic interaction and that the ionic character of the bond diminishes on hydrogen bonding. The calculated and the observed values of the frequencies agree only when the two possible resonance structures in amides are taken into consideration for calculations.
Volume 56 Issue 3 September 1962 pp 115-124
A new procedure has been adopted in subjecting formamide—a molecule which has no symmetry—to normal co-ordinate treatment by the Wilson’s F-G matrix method. The molecule is split into two parts for the purposes of calculation. One part is and the other is where R is the CHO group. Both the parts have C-N bond in common. Assuming the part one to be planar and the part two to be pryamidal as suggested by Costain and Dowling, the normal co-ordinate treatment of both the parts has been carried out and the fundamental frequencies calculated. The close agreement between the observed and the calculated values confirms the non-planar structure of formamide. Among all the fundamental frequencies, the frequency due to C-N stretch alone appears to be mass sensitive. On the basis of all these considerations some of the frequencies have been assigned to the wagging and twisting modes, which are different from those that are assigned by Evans.
Volume 56 Issue 3 September 1962 pp 155-163
The free OH and NH stretching frequencies of methanol, ethanol, formic and acetic acids and of N-methyl acetamide are used to calculate the shift in their frequencies due to hydrogen bonding. These calculations are based on the fact that the hydrogen bonding is an electrostatic interaction and that the ionic character of the bond diminishes on hydrogen bonding. The observed and the calculated bonded stretching frequencies agree fairly in methanol and ethanol, but in formic and acetic acids and N-methyl acetamide, the agreement between the corresponding observed and calculated frequencies is obtained only when the two possible resonance structures in these molecules are taken into consideration for calculations.
Volume 56 Issue 5 November 1962 pp 233-238
Diphenyl methane has been subjected to normal co-ordinate treatment assuming the phenyl groups to be point masses. The Wilson F-G matrix method has been employed to obtain the secular equation in order to calculate the fundamental frequencies. In calculating the thermodynamic properties, contributions from the ring frequencies are also included.
Volume 58 Issue 1 July 1963 pp 29-37
A charge transfer theory of the hydrogen bond has been developed by using a combination of the Second Order Perturbation and Molecular Orbital Theories. Expressions have been derived for both frequency shifts in the X-H stretching frequency and the changes in the infra-red integrated intensity. A relation between the frequency shifts and the changes in the intensity has also been worked out.
Volume 58 Issue 6 December 1963 pp 327-335
The infra-red-integrated intensity of the SH band in thiophenol and in its complexes with a number of electron donors was measured. The increase in the value of
Volume 58 Issue 6 December 1963 pp 368-372
The mean amplitudes of the vibrations of C = O and C − CPh stretching modes of benzophenone have been evaluated with the help of L matrices and the percentage contribution of different normal modes to the C=O and C−CPh stretching modes are given.
Volume 67 Issue 2 February 1968 pp 99-108
The vibrational spectra of urea and deuterated urea have been recorded. Using a most general potential function, the force constants and the mean amplitudes of vibration have been calculated.