• M R Padhye

      Articles written in Proceedings – Section A

    • The effect of substitution on the light absorption of naphthalene

      M R Padhye N R Rao K Venkataraman

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      A qualitative method for assigning the longest wavelength band in the absorption spectra ofα- andβ-monosubstituted naphthalene derivative to polarizations in definite directions has been devised. The longest wavelength band in the absorption spectra ofα-substituted derivatives is shown to be due to polarization along the short axis of the molecule; in the spectra of theβ-substituted derivatives the longest wavelength band is due to polarization along the long axis of the molecule. The absorption spectra of four isomeric hydroxynaphthoic acids have been determined, using dioxane as solvent. The deeper colour of 2:3-hydroxynaphthoic acid in comparison with the isomeric acids is explained as due toβ:β-disubstitution in the naphthalene nucleus. The absorption spectra of 2-methoxy-1-naphthoic acid, 2-methoxy-3-naphthoic acid and 2-methoxy-6-naphthoic acid are discussed.

    • Anthraquinone and anthrone series - Part XI. Steric hindrance in dibenzanthronyls and dibenzanthrones

      M R Padhye N R Rao K Venkataraman

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      The absorption spectra of dibenzanthrone, 16: 17-dihydroxydibenzanthrone, 16: 17-and 3: 12-dimethoxydibenzanthrone have been determined ino-chlorophenol. The bathochromic shift of the dibenzanthrone spectrum on substitution of two methoxyl groups in the 16: 17-positions of dibenzanthrone is ascribed to the over-riding tendency of the dibenzanthrone ring system to remain planar and hence force the methoxyl groups also to be coplanar with the ring system.

      The absorption spectra of 3:3′- and 4:4′-dibenzanthronyls have been reported and discussed.

    • Absorption spectra of substituted thianaphthenes

      M R Padhye R P Punyarthi

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      The near ultraviolet absorption spectra of 5-chlorothianaphthene and 7-bromothianaphthene have been investigated in the region 3050 to 2800 Å and 3050 to 2850 Å respectively—corresponding to longest wavelength system. The tentative vibrational assignments are put forward for the prominent bands. The assignment of certain frequencies are discussed with respect to the effect of substitution (Cl or Br) in the phenyl part of the thionaphthene nucleus.

    • Infra-red spectra of fluoroxylenes

      M R Padhye T S Varadarajan

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      The infra-red spectra of four fluoroxylenes (1, 2, 6-, 1, 2, 3-, 1, 3, 4-and 1, 2, 5-isomers) have been recorded in the 2–15 µ region on a Perkin-Elmer Model 21 spectrophotometer. From among the bands recorded, those which could be correlated to the fundamental vibration of the constituent benzene and methyl groups are discussed in detail and compared with particular reference to the type of substitutions.

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