Some new reactions of coumarins

The direction of the reaction of coumarin derivatives with o-phenylenediamine depends on their structure, leading to 2-(2 -hydroxyphenyl)benzimidazole in the case of unsubstituted coumarin and to derivatives of benzimidazo[1,2-a]quinoline in the case of 7-amino-substituted coumarins.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1053–1055, August, 1992.     

Synthesis and electronic absorption spectra of substituted tetrabenzoporphins

Zinc complexes of tetrabenzoporphins with substituents in the benzene fragments of the molecule were synthesized by the template tetramerization of substituted 3-carboxymethylphthalimidines or phthalimides with malonic or phenylacetic acid in the presence of zinc acetate, as well as by substitution reactions in the tetrabenzoporphin molecule. The metal-free compounds were obtained from the corresponding zinc complexes by the action of a stream of hydrogen chloride in chloroform. The electronic absorption spectra of the synthesized compounds were investigated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 773–779, June, 1988.     

Nature of the fluorescent states of quinoline analogs of styryl and distyrylanthracene

Study of the photophysical properties of quinoline analogs of 9-styryl and 9,10-distyrylanthracenes showed that, in contrast to the case of 9-[-(2-quinolyl)vinyl]anthracene, the intramolecular geometrical relaxation process plays a decisive role in the formation of the excited state of 9,10-di-[-(2-quinolyl)vinyl]-anthracene.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 824–829, June, 1987.     

Phthalocyanines and Related Compounds: XL. Synthesis of β-Diethylaminoethyl-substituted Octa-4,5-carboxyphthalocyanine Tetraimides and Their Quaternary Salts

Cobalt, zinc, hydroxoaluminum, and iron complexes of N,N′,N″,N?-tetrakis(β-diethylaminoethyl) phthalocyanine-2,3 : 9,10 : 16,17 : 23,24-tetrakis(dicarboxamide) were synthesized and were converted into the corresponding water-soluble quaternary salts by treatment with methyl iodide, methyl p-toluenesulfonate, diethyl and dimethyl sulfates, and trimethyl phosphate. The electronic absorption spectra of the quaternary salts indicated their considerable aggregation in aqueous solution; the degree of aggregation decreases in going to solutions in ethanol and disappears in DMSO.     

Spectroscopy, electrochemistry, and molecular orbital calculations of metal-free tetraazaporphyrin, -chlorin, -bacteriochlorin, and -isobacteriochlorin

Metal-free tetraazachlorin (TAC), -bacteriochlorin (TAB), and -isobacteriochlorin (TAiB) were characterized by electronic absorption, magnetic circular dichroism (MCD), fluorescence, and time-resolved ESR (TR-ESR) spectroscopy, and by cyclic voltammetry. The results are compared with those of metal-free tetraazaporphyrin (TAP). The potential difference DeltaE between the first oxidation and reduction couples decreases in the order TAP>TAiB>TAC>TAB. The splitting of both the Q and Soret bands decreases in the order TAB>TAC>TAP>TAiB. Corresponding to the split absorption bands, MCD spectra show a minus-to-plus pattern with increasing energy in both the Q and Soret regions, which suggests that the energy difference between the HOMO and second HOMO is larger than that between the LUMO and second LUMO. These spectroscopic properties and redox potentials were reproduced by molecular orbital calculations using the ZINDO/S Hamiltonian. The fluorescence quantum yields of the reduced species are much smaller than that of TAP. The zero-field splitting (ZFS) parameters D and E of the excited triplet states (T1) of these species decrease and increase, respectively, on going from TAP to TAC and further to TAB. The D and E values of TAiB are larger than those of the other species. The results are supported by the absence of interaction between the spin over reduced pyrrole moieties of the HOMO and over the LUMO, and by calculations of ZFS under a half-point-charge approximation.     

Synthesis of meso-tetraalkyltetrabenzoporphines

Stable complexes of zinc meso-tetralkyltetrabenzoporphines with tribenzylamine have been obtained by the template tetramerization of 3-R-methylenephthalimidines with zinc acetate in the presence of tribenzylamine or by the reaction of potassium phthalimide with the corresponding alkylmalonic acids. The structures of the compounds synthesized have been confirmed by their electronic absorption spectra, and in some cases also by their mass spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 61–64, January, 1984.     

Aggregation properties of copper dibenzo-barrelenophthalocyanine

Depending on the solvent in which they are placed or from which they have been obtained, sterically hindered copper octa-tert-butyltetra-4,5-dibenzobarrelenophthalocyanines in solution and as a powder can take a monomeric form or dimer or trimer aggregate forms. In the aggregates, the molecules are disposed opposite one another around a high-order axis at an angle of 45° from equatorial displacement.Institute for the Chemistry of Natural Organic Materials, Russian Academy of Sciences, Krasnoyarsk 660000. Scientific-Research Institute for Organic Itermediates and Dyes, Moscow 103787. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 171–175, February, 1995. Original article submitted December 22, 1994.