Georgi Dobrikov - Academia.edu (original) (raw)

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Papers by Georgi Dobrikov

Cheminform, 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Journal of Physical Chemistry A, 2010

The excited-state dynamics of five derivatives of the GFP-chromophore, which differ by the positi... more The excited-state dynamics of five derivatives of the GFP-chromophore, which differ by the position and nature of their substituents, has been investigated in solvents of various viscosity and polarity and in rigid media using femtosecond-resolved spectroscopy. In polar solvents of low viscosity, like acetonitrile or methanol, the fluorescence decays of all compounds are multiexponential, with average lifetimes of the order of a few picoseconds, whereas in rigid matrices (polymer films and low temperature glasses), they are single exponential with lifetimes of the order of a few nanoseconds and fluorescence quantum yields close to unity. Global analysis of the fluorescence decays recorded at several wavelengths and of the transient absorption spectra reveals the presence of several excited-state populations with slightly different fluorescence and absorption spectra and with distinct lifetimes. These populations are attributed to the existence of multiple ground-state conformers. From the analysis of the dependence of the excited-state dynamics on the solvent and on the nature of the substituents, it follows that the nonradiative deactivation of all these excited chromophores involves an intramolecular coordinate with large amplitude motion. However, depending on the solvent and substituent, additional channels, namely, inter-and intramolecular hydrogen bond assisted nonradiative deactivation, are operative. This allows tuning of the excited-state lifetime of the chromophore. Finally, an ultrafast photoinduced intramolecular charge transfer is observed in polar solvents with one derivative bearing a dimethylaminophenyl substituent.

Tetrahedron-asymmetry, 2001

The addition of Me 3 SiCN and LiCH 2 CN to (+)-camphor and (−)-fenchone, respectively, followed b... more The addition of Me 3 SiCN and LiCH 2 CN to (+)-camphor and (−)-fenchone, respectively, followed by reduction leads to chiral band g-aminoalcohols. The enantioselectivities realized using these aminoalcohols as ligands in the addition of Et 2 Zn to benzaldehyde were lower than those obtained using the corresponding d-aminoalcohols.

Journal of Heterocyclic Chemistry, 2006

A series of 2-substituted-4(3H)-quinazolinones 13-20 has been synthesized in good yields using th... more A series of 2-substituted-4(3H)-quinazolinones 13-20 has been synthesized in good yields using the reaction of double lithiated 2-methylquinazolinone-4 with a variety of aromatic aldehydes. They have been easily transformed in high yields into the corresponding 2-substituted conjugated derivatives 21-28 bearing terminal aryl groups by F3CCOOH mediated dehydration.