N R Rao
Articles written in Proceedings – Section A
Volume 34 Issue 6 December 1951 pp 355-367
The relation between chemical constitution and chromatographic adsorbability of a series of aminoanthraqunones and their derivatives has been investigated. Of the various types of interaction of which alumina appears to be capable in the process of adsorption, the most important is hydrogen bonding between alumina and one or more proton-donor groups in the adsorptive. When anthracene, anthraquinone and a series of aminoanthraquinones and their derivatives are chromatographed on alumina, using benzene as solvent for adsorption and development, the strength of adsorption is in the following increasing order: anthracene, anthraquinone, N-methyl-1-aminoanthraquinone, 1-benzamidoanthraquinone, 1:4-bis-methylaminoanthraquinone, 1-aminoanthraquinone, 1:5-diaminoanthraquinone and N-methyl-2-aminoanthraquinone, 1:8-diaminoanthraqunione, N-methyl-1-benzamidoanthraquinone and N-methyl-2-benzamidoanthraquinone, 2-aminoanthraquinone, 1:4-diaminoanthraquinone, 1:4:5-triaminoanthraquinone, 1:2-diaminoanthraquinone, 1:4:5:8-tetraminoanthraquinone, 2:6-diaminoanthraquinone. The relative adsorption affinities are explained in terms of chelation between NH2 and CO groups, resonance interaction between NH2 and CO groups, the ability of amide groups to form hydrogen bonds, and the electron-repulsive effect of methyl groups.
Volume 38 Issue 4 October 1953 pp 297-306
A qualitative method for assigning the longest wavelength band in the absorption spectra of
Volume 38 Issue 4 October 1953 pp 307-319
The absorption spectra of dibenzanthrone, 16: 17-dihydroxydibenzanthrone, 16: 17-and 3: 12-dimethoxydibenzanthrone have been determined in
The absorption spectra of 3:3′- and 4:4′-dibenzanthronyls have been reported and discussed.