Ambident chemosensors based on benzo[<Emphasis Type="Italic">h</Emphasis>]chromen-2-one

Schiff bases derived from 7-hydroxy-4-methyl-2-oxobenzo[h]chromene-8-carbaldehyde in solution exist as equilibrium mixtures of benzoid and quinoid tautomers. The fraction of the quinoid tautomer increases with rise in solvent polarity. The Schiff base containing a benzo-15-crown-5 fragment on the nitrogen atom was shown to be a new ambident chemosensor capable of selectively binding transition metal cations via reaction at the o-hydroxyaldehyde imine fragment and alkaline-earth metals via host-guest interaction with the crown ether moiety. This compound exhibits a pronounced sensor activity toward Mg²⁺ and Ba²⁺ ions and is a selective naked-eye fluorescent chemosensor for Cu²⁺ and Co²⁺ ions.     

Synthesis and Spectral-Luminescent Properties of Fluorescent Dyads Based on Tetraarylimidazole and Azomethines of Various Nature

Russian Journal of General Chemistry - Synthesis and structure of two novel dyads including two fluorophores - 1,2,4,5-tetraarylimidazole and azomethine fragments of different nature, have been...     

Molecular Switching and PET Effect in the Molecules of 2-(9-Anthrylmethylaminomethylene)benzo[b]thiophene and Its N-Acetyl Derivative

Russian Journal of Organic Chemistry -     

2-[N-Acetyl-N-(2-fluorenonyl)aminomethylene]benzo[b]- thiophen-3(2H)-one,a Molecular Fluorescent Switch

Russian Journal of Organic Chemistry -     

Synthesis, structures, and photochromic properties of N-aryl-3-indolylfulgides

New 3-indolylfulgides, viz., 3-[1-(1-aryl-5-methoxy-2-methyl-1H-indol-3-yl)ethylidene]-4-(1-methylethylidene)tetrahydro-2,5-furandiones, were synthesized. These compounds were obtained as E-isomers, as demonstrated by X-ray diffraction, electronic spectroscopy, and ¹H NMR spectroscopy. Fulgides exhibit photochromic properties in solution. The cyclic dihydrocarbazole photoisomers of indolylfulgides show fluorescence properties and are characterized by high thermal stability. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1417–1423, July, 2008.     

Novel reactions of ninhydrin oxime with mercaptoalkanoic acids

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Spiropyrans and spirooxazines 9. Photochromism of novel cationic spirooxazines

Novel photochromic spirooxazinoquinolines, their cationic derivatives, and cationic spirooxazine containing pyridinium cation in the aliphatic side chain of the oxazine moiety of the molecule were synthesized. Quaternization of the quinoline fragment leads to a substantial increase in the thermal stability of the merocyanine isomers of cationic spirooxazines and a decrease in the efficiency of photocoloration. Pyridinium cation in the aliphatic side chain of the spirooxazine does not exert a substantial effect on the kinetics of photocoloration and thermal bleaching.     

Synthesis,structure, and properties of new spirooxindolodibenzodiazepine derivatives

An acid-catalyzed reaction of 3-(2-aminophenylamino)-5,5-dimethylcyclohexen-1-one with isatines leads to the formation of the earlier undescribed 3,3-dimethyl-2,3,4,5,10,11-hexahydrospiro[1H-dibenzo[b,e][1,4]diazepine-11,3′-2H-indole]-1,2′-dione derivatives (6). Spiranes 6 upon heating undergo auto-redox rearrangement with disintegration to 3,3-dimethyl-1,2,3,4-tetrahydrophenazine and the corresponding oxindole. Crystals of four derivatives of compound 6 were studied by X-ray diffraction method.     

Benzenoid-quinoid tautomerism of azomethines and their structural analogs. 42. Synthesis,structures, and spectral-luminescence properties of 3-hydroxy-2-acetylbenzo[b]thiophene imines

N-Aryl- and N-alkylimines of 3-hydroxy-2-acetylbenzo[b]-thiophene, the most stable isomeric form of which, according to the UV, IR, and ¹H NMR spectra data, is the E-keto enamine structure, were synthesized. Irradiation of the aminovinyl ketones in the region of the long-wave absorption band causes thermally and photochemically reversible EZ isomerization. 2-Aminoethylidene-3-(2H)-benzo[b]thiophenones have low-intensity fluorescence with a normal Stokesian shift, which is absent in solutions of their lithium and sodium salts.See [1] for Communication 41.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 591–595, May, 1989.