Yuri V. Fedorov

Cation-dependent fluorescent properties of naphthalimide derivatives with N-benzocrown ether fragment.

The investigation of N-phenyl-4-amino- and N-phenyl-4-acetamido-1,8-naphthalimides containing N-benzo-15-crown-5 ether substituent showed that the presence of ionophoric fragment as N-substituent in naphthalimide molecule provides the design of compound possessing the properties of fluorescent receptor. The addition of metal cations does not change the position of absorption and emission bands but substantial increases the fluorescence intensity. The study of molecules included the theoretical and experimental (optical, NMR) methods, analysis of intramolecular charge (electron) transfer and fluorescence properties in the presence and absence of metal ions.

Supramolecular assemblies of photochromic benzodithia-18-crown-6 ethers in crystals, solutions, and monolayersElectronic supplementary information (ESI) available: crystal data, data collection, and structure solution and refinement parameters. See http://www.rsc.org/suppdata/nj/b1/b110630a/

We studied the assembly of dithiacrown ether styryl dye (CSD) molecules in crystals, solutions, and films in the presence of metal cations. X-Ray diffraction data allowed us to conclude that the anion affects the supramolecular architecture of CSDs in the crystal, specifically, the type of stacking of the dye molecules. In solution, in the presence of Pb2+, CSD molecules with the betaine structure spontaneously form dimeric complexes consisting of two dye molecules and two metal cations, with a fixed mutual arrangement of the double bonds. The dimer complex is stable due to coordination between the anion substituent of one molecule and the metal cation located in the crown ether cavity of the other molecule. Irradiation of the dimer complexes leads to regio- and stereoselective [2 + 2]-cycloaddition, giving only one cyclobutane derivative of the eleven theoretically possible products. The other photoreaction studied for CSDs is reversible Z–E isomerization. Due to its specific structure, the betaine-type CSD is able to form the ‘anion-capped’ Z-isomer. Intramolecular coordination in the ‘anion-capped’ isomer enhances its stability and causes a sharp deceleration of its dark Z–E isomerization. The amphiphilic CSD forms relatively stable monolayers on distilled water and various aqueous salt subphases. The results obtained indicate that it is possible to distinguish between two types of the dye monolayer structures based on the presence of alkali or heavy metal cations in the aqueous subphase.

Cucurbit[7]uril Complexes of Crown-Ether Derived Styryl and (Bis)styryl Dyes

In this paper, we report the interaction of the CB[7] molecular container with crown ether styryl and (bis)styryl dyes 1-6. The interaction of monostyryl dyes (1 and 2) with CB[7] results in the formation of 1:1 complexes where the CB[7] molecule is located on the region of the guest encompassing the pyridinium ring, C=C double bond, and a portion of the aryl ring of benzocrown ethers 1 and 2. For (bis)styryl dyes (3-5), the formation of two types of complexes with composition dye.CB[7].dye and CB[7].dye.CB[7] was confirmed by a combination of optical and electrospray ionization mass spectroscopy (ESI-MS) methods. In the case of (bis)styryl dye (6), both 2:1 and 1:1 compositions 6.CB[7].6 and CB[7].6 were formed. Complex formation is accompanied by substantial changes in the optical characteristics of the dyes and formation of long-lived excimer species. We tested the stimuli responsiveness of this system in response to metal ions. We find that the metal ions prefer to bind to the electrostatically negative ureidyl C=O portals of the CB[7] rather than with the crown ether moiety of the styryl dyes.

Regiospecific C–N Photocyclization of 2-Styrylquinolines

Regiospecific C-N photocyclization of 2-styrylquinolines resulting in formation of potentially biologically active quino[1,2-a]quinolizinium derivatives was investigated. The presence of strong electron-donating groups in the phenyl ring reveals to be a crucial factor managing photocyclization effectiveness. Introduction of a crown ether moiety allows changing the photoreaction parameters by means of complexation with Mg(ClO4)2.

Metal Ions Drive Thermodynamics and Photochemistry of the Bis(styryl) Macrocyclic Tweezer

UV/Vis and NMR spectroscopy were used for the structural elucidation and thermodynamic and photochemical studies of the metal-coordinated crown-containing macrocyclic tweezer (E,E)-1. The bis(styryl) tweezer (E,E)-1 formed two types of complexes with magnesium(II): a 1:1 intramolecular asymmetric sandwich complex [(E,E)-1].Mg(2+) and a 1:2 complex [(E,E)-1].(Mg(2+))(2). In the former case, there is direct cation intramolecular exchange (0.299 s(-1), DeltaG(++)=69.4 kJ mol(-1)) between two parts of the bis(styryl) tweezer (E,E)-1. Addition of barium(II) to the bis(styryl) tweezer (E,E)-1 led to an intramolecular centrosymmetric sandwich 1:1 complex [(E,E)-1].Ba(2+). Irradiation of [(E,E)-1]Ba(2+) afforded reversible intramolecular [2pi+2pi] photocyclization with excellent stereoselectivity and quantitative yield. In contrast, irradiation of [(E,E)-1].(Mg(2+))(2) resulted in reversible stepwise E,Z-isomerization.

Supramolecular control of photochemical and electrochemical properties of two oligothiophene derivatives at the air/water interface.

Two geometric isomers of oligothiophene derivatives containing two crowned styryl fragments in 2- or 3-positions of thiophene rings are able to form stable monolayers on the water subphase. The organizing of crown-containing oligothiophenes in monolayers is guided by the π-stacking interaction of hydrophobic styrylthiophene fragments and interaction of hydrophilic macrocycles with the water subphase. The difference in structure of oligothiophene molecules leads to the formation of distinct monolayer architectures with various electrochemical and optical characteristics.

Spectroscopical study of bacteriopurpurinimide-naphthalimide conjugates for fluorescent diagnostics and photodynamic therapy.

Two novel bis(chromophoric) dyads ABPI-NI1 and ABPI-NI2 containing 1,8-naphthalimide and bacteriopurpurinimide units linked by p-phenylene-methylene (ABPI-NI1) and pentamethylene (ABPI-NI2) spacers were prepared to test their ability to be used in the design of effective agents for both photodynamic therapy (PDT) and fluorescent tumor imaging. Photophysical studies revealed that the emission from the naphthalimide chromophore in both conjugates was partially quenched due to resonance energy transfer between the photoactive components. Compound ABPI-NI2 with more sterically flexible oligomethylene group demonstrated higher fluorescence intensity as compared with that for ABPI-NI1.

Equilibrium between Two Degenerated Forms during Complexation of Novel Bis-crown Containing Bithiophene and Alkanediammonium Cations

Синтезирован 2,2’-дизамещенный битиофен с двумя 18-краун-6-эфирными группами и изучено его комплексообразование с перхлоратами алкандиаммония методами спектрофотометрического титрования, 1Н ЯМР-спектроскопии, масс-спектрометрии и циклической вольтамперометрии. Показано, что краун-эфирные фрагменты замещенного битиофена в растворе ацетонитрила связывают катионы диаммония с образованием динамических комплексов состава 1:1. Методом масс-спектрометрии подтверждена стехиометрия комплексов. На основе данных 1Н ЯМР-спектроскопии предложена структура супрамолекулярных ансамблей.