Valuk V. Synthesis and fluorescent properties of hexahydrodicyclopenta[b,e]-pyridines, their salts and dihydroderivatives.

With the objectives to study the fluorescent properties and to develop new types of ion- and pH sensors the series of hexahydrobicyclopenta[b,e]pyridines, octahydrobicyclopenta-[b,e]pyridines with different electron donor aromatic substituents in the positions 3, 5, 8, and the appropriate N-alkyl- or N-arylpyridinium salts were synthesized. Then aminomethyl, carboxy, alkyl and acyl-derivatives of hexahydrobicyclopenta[b,e]pyridines were synthesized by chemical modification of their molecules. The level of planarity of the synthesized compounds in the solutions as well as their EE-configuration were estimated by the data of 1Н-NMR, electron absorption and fluorescence spectrometry. It was found the most planar molecular conformation is typical for the compounds with five-membered side aromatic moieties. In the case of pyridines with six-membered aromatic residues the steric hindrance appears which results in turning the residues out of the plane of the central pyridine moiety. The violation of planarityin this case saves the possibility of -electronic conjugation in the molecule. The regularities between the nature of solvent, the chemical structure or the conformation of the molecule and fluorescence properties of a substance were estimated and explained. The both forms - neutral and protonated are characterized by high fluorescence quantum yields. Spectral and basic properties of studied compounds can be regulated in wide range by the insertion of electron donor substituents in side aromatic rings.