Browsing by Author "Bojinov V."
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Item A novel 1,8-naphthalimide probe for selective determination of Hg2+ in a wide pH window(2018-01-01) Krasteva P.; Dimitrova M.; Georgiev N.; Bojinov V.This paper reports the synthesis and photophysical investigation of a novel 1,8-naphthalimide fluorophore containing 2-amino-1,3,4-thiadiazole fragment at C-4 position. Absorption and fluorescence characteristics of the dye as a function of pH were investigated in water/ethanol (1:1, v/v) solution. It was found that the synthesized 1,8-naphthalimide did not show significant changes in the emission properties in a wide pH range. Furthermore the ability of the synthesized compound to detect cations was evaluated by the changes in its fluorescence intensity in the presence of metal ions (Co2+, Cu2+, Fe3+, Ni2+, Pb2+, Cd2+, Zn2+ and Hg2+). Only Hg2+, among the tested metal ions, was efficiently detected due to the aggregation caused quenching process. The results obtained indicate the potential of the novel compound acting as a fluorescent ``onoff`` switch for selective determination of Hg2+ in a wide pH window.Item Photoisomerization of triazine-stilbene fluorescent brighteners in solution and in their copolymers with styrene(2000-01-01) Grabchev I.; Bojinov V.The paper reports on the photochemical trans-cis isomerization of some new polymerizable triazinestilbene fluorescent brighteners and their copolymers with styrene in aqueous and ethanol solutions. A dependence of trans-cis isomers in solution equilibrium and in solid polymeric films on the nature of the substituent in the triazine ring has been found.Item Synthesis and properties of adducts of a hindered amine and 2-hydroxyphenylbenzotriazole as novel polymer stabilizers(2002-05-17) Bojinov V.The synthesis of new types of stabilizers (a combination of 2,2,6,6-tetramethylpiperidine and 2-hydroxyphenylbenzotriazole in one molecule) is reported. Six polymerizable combined stabilizers as well as two unsaturated triazinyl-2,2,6,6-tetramethylpiperidines and three unsaturated triazinyl-2-hydroxyphenylbenzotriazoles as individual stabilizers were synthesized. Their copolymers and the terpolymers of the individual stabilizers with methyl methacrylate were obtained. Chemical bonding of the stabilizers in the polymer was confirmed spectrophotometrically. The influence of these additives on the photostability of the copolymers was studied. The participation of the combined stabilizers in the polymerization did not affect considerably the rate of copolymerization, the molecular weight and polydispersity of the copolymers. A significant stabilizing effect against photodegradation was determined. © 2002 The Royal Society of Chemistry and Owner Societies.Item Synthesis, chemosensing properties and logic behaviour of a novel ratiometric 1,8-naphthalimide probe based on ICT and PET(2016-08-01) Georgiev N.; Dimitrova M.; Todorova Y.; Bojinov V.A novel fluorescence sensing 1,8-naphthalimide designed on the ``receptor1-fluorophore-spacer-receptor2`` model is synthesized and investigated. The novel probe comprising aminotriazole and hydroxyphenyl substituents is capable to operate simultaneously via ratiometric ICT and PET signalling mechanism. The synthesized compound shows excellent signalling properties towards protons, hydroxyl anions and Cu2+ ions. Due to the remarkable fluorescence changes in the presence of these analytes the system is able to act as a two output combinatorial logic circuit with three chemical inputs. Input3-Disabled XNOR, INHIBIT and IMPLICATION logic gates were obtained. Because of the parallel action of disabled-XNOR and disabled-INHIBIT gates a magnitude digital comparator with disable capability is achievable.