Effect of the heteroatom on the energies of the boundary molecular orbitals of dibenzo derivatives of five-membered heterocycles

The effect of the heteroatom on the energy characteristics of their boundary molecular Orbitals was studied by investigation of the charge-transfer complexes (CTC) of the dibenzo derivatives of five-membered heterocycles. Tetramethyl-substituted dibenzo derivatives of five-membered heterocycles were investigated as electron donors, and their corresponding dianhydrides were investigated as electron acceptors. Their ionization potentials and electron affinities, respectively, were determined. From the regularities in the change in these characteristics it was concluded that replacement of one heteroatom by another leads to approximately identical energy shifts of both boundary molecular orbitals.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 185–187, February, 1979.     

Preparation and properties of derivatives of dithiolylidene-(4′-phenyldiazonium)acetonitrile

Thefluoroborates of (4,5-dimethyl-1,3-dithiolylidene)-(4-phenyldiazonium)acetonitrile and (4,5-ethylenedithio-1,3-dithiolylidene)-(4-phenyldiazonium)acetonitrile have been prepared; these compounds are photosensitive in the visible region of the spectrum. The quantum yield in the photolysis of the fluoroborates in acetonitrile solution amounts to 0.1 moteleinstein.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, p. 179–181, February, 1994. Original article submitted November 29, 1993.     

Calculation of the electronic spectrum within the CNDO/S (complete neglect of differential overlap/S) approximation and character of the long-wave absorption band of 2-N-pyridinia-1,3-indandione betaine

The electronic spectrum of 2-N-pyridinia-1,3-indandione betaine was calculated by the MO LCAO method within the CNDO/S approximation with the Del Bene-Jaffe parametrization in order to refine the concepts regarding the character of the longwave absorption band of this compound. It was established that the long-wave absorption band of this compound is due to an electron transition with charge transfer and has a vibrational structure.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 658–661, May, 1981.     

2-N-Imidazolyl- and 2-N-pyrazolyl-1,3-indandiones

It was shown by spectroscopic methods that 2-N-imidazolyl-, 2-N-(N-methylimidazolyl)-, and 2-N-(N-methylpyrazolyl)-1,3-indandiones exist in the form of inner salts, whereas 2-N-pyrazolyl-1,3-indandione exists in the form of an enol with an intramolecular hydrogen bond.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1082–1085, August, 1982.     

Ring-chain isomerism and reactions of 2-(1-anthraquinonecarbonyl)-1,2,3,4-tetrahydrophthalazine

The ring isomer of the corresponding acyl derivative — 5,9-dioxo-17a-hydroxy-9,10,11,16-17,17a-hexahydro-5H-dibenzo[d,e,h]phthalazino[2,3-a]cinnoline — was obtained by acylation of 1,2,3,4-tetrahydrophthalazine with anthraquinone-1-carboxylic acid chloride. Treatment of the product with thionyl chloride or hydrogen chloride gave the deeply colored 5,9-dioxo-9,10,11,16-tetrahydro-5H-dibenzo[d,e,h]phthalazino[2,3-a]cinnolinium chloride. The possibility of charge transfer between the chloride anion and the phthalazinium cation is examined as a reason for the deep coloration. This compound very readily undergoes hydrolytic oxidative cleavage at the C-N bond to give 2-(2-formylbenzyl)-3,7-dioxo-2,3-dihydro-7H-dibenzo[d,e,h]cinnoline.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1411–1415, October, 1977.