Tuning of the fluorescence properties of nitrogen heterocyclic compounds by polar substituents

In this work several series of novel fluorescent organic systems, distinguished by sensitivity to effects of the surrounding media and structural changes as well as the biological activity and similarity to some DNA fragments, are being investigated. A detailed examination of the photophysical properties of novel pyrimidine, pyrrolo[2,3-d]pyrimidine and purine derivatives is carried out and the tuning possibilities of their optical properties by modifying new compounds with substituents of various polarity and morphology are analyzed. Special emphasis is placed on the radiative and non-radiative excitation relaxation mechanisms. This work demonstrates that the nitrogen heterocyclic fragments in conjunction with polar substituents form the intramolecular charge transfer complexes and their fluorescence properties are sensitive to the polarity changes of the surrounding media and the substituents, as well as variation of their morphology and intramolecular twisting. This dissertation is also aimed at exploring the opportunities of applications of the new compounds for fluorescent metal ion sensing and formation of fluorescent nano-aggregates