Browsing by Author "Kovalev I.S."

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1-Hydroxypyrene-based micelle-forming sensors for the visual detection of RDX/TNG/PETN-based bomb plots in water
(Royal Society of Chemistry, 2018) Kovalev I.S.; Taniya O.S.; Kopchuk D.S.; Giri K.; Mukherjee A.; Santra S.; Majee A.; Rahman M.; Zyryanov G.V.; Bakulev V.A.; Chupakhin O.N.
The high-lying LUMO energy levels of common aliphatic nitro-explosives require special approaches for the proper synthetic design of fluorescence chemosensors that are capable to detect ultra-trace amounts of these explosives via photo-induced electron transfer (PET) fluorescence quenching. Herein, 1-hydroxypyrene has been used as a synthetic platform to prepare a number of water soluble micelle-forming fluorescent chemosensors possessing high-lying LUMO levels. Based on these sensors a cheap and highly efficient method has been described for the detection of low-volatile aliphatic nitro explosives, such as 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), pentaerythritoltetranitrate (PETN), and high volatile taggants/propellants, such as 2,3-dimethyldinitrobutane (DMDNB) or trinitroglycerin (TNG) in aqueous solutions and in vapor phase. The applicability of the sensors for the detection of nitro-explosives was fully confirmed based on the fluorescence quenching titration experiments, with the corresponding Stern–Volmer constants as high as 6.0 × 105 M−1 and the limit of detection (LOD) as low as 12 ppb. The “sphere of action” quenching mechanism has been proposed. To support this, the DFT calculations of the possible molecular complexes between the sensors and nitro-analytes were performed along with the calculations of the quenching sphere radii for the Perrin's model.
Solvent-free synthesis of 5-(aryl/alkyl)amino-1,2,4-triazines and ?-arylamino-2,2?-bipyridines with greener prospects
(Royal Society of Chemistry, 2017) Kopchuk D.S.; Chepchugov N.V.; Kovalev I.S.; Santra S.; Rahman M.; Giri K.; Zyryanov G.V.; Majee A.; Charushin V.N.; Chupakhin O.N.
A green and highly efficient method has been developed for the synthesis of 5-(aryl/alkyl)amino-1,2,4-triazines and ?-arylamino-2,2?-bipyridines according to the principles of atom economy. It has been performed by two consecutive solvent-free reaction pathways: the ipso-substitution of a cyano-group in 5-cyano-1,2,4-triazines and the aza-Diels-Alder reaction of the resulting 5-arylamino-1,2,4-triazines with 1-morpholinocyclopentene used as a dienophile. Solvent and catalyst-free conditions, operational simplicity, the compatibility with various functional groups, nonchromatographic purification technique, and high yields are the notable advantages of this procedure. The present methodology possesses a low E-factor.
Synthesis and photophysics of new unsymmetrically substituted 5,5?-diaryl-2,2?-bypiridine-based “push-pull” fluorophores
(Elsevier Ltd, 2019) Starnovskaya E.S.; Kopchuk D.S.; Khasanov A.F.; Tanya O.S.; Santra S.; Giri K.; Rahman M.; Kovalev I.S.; Zyryanov G.V.; Majee A.; Charushin V.N.
New unsymmetrically substituted 5,5?-diaryl-2,2?-bypiridine “push-pull “ fluorophores were prepared in good yields via the “1,2,4-triazine method “/Suzuki coupling reaction sequence. The obtained fluorophores contain the “push-pull “ system with donor and acceptor moieties arranged in a D-?-A-?-D fashion, and that provides both the prospective photophysical properties and unique solvatocromic effects for the most representative compounds.