Alla Bobylyova

Metal ion modulated torsion angle in a ditopic oligothiophene ligand: toward supramolecular control of π conjugation.

A π-conjugated oligomer bearing two 15-crown-5-containing styryl moieties connected at the inner β positions of the terminal thiophene nuclei can adopt either a U or a Z shape depending on the structures of its complexes with magnesium and barium ions. We show that barium cations lead to the formation of a mononuclear complex in solution, which causes the system to fold into the U shape. Magnesium ions lead to the same effect at low concentration, but force the ligand to adopt the Z-shaped geometry at high concentrations favoring formation of a binuclear complex. These geometrical reorganizations in solution are accompanied by profound changes in spectroscopic properties, which can be rationalized in terms of variations in the extent of electron delocalization along the oligothiophene backbone. The effects are analyzed by mass spectrometry and (1)H NMR, UV/Vis absorption, and fluorescence spectroscopy in the steady-state and time-resolved regimes. The experimental results are compared to data calculated by using MOPAC2007 with the PM6 Hamiltonian including the COSMO solvation model.

Synthesis, complex-formation, and extracting ability of new derivatives of dithia-13(16)-crown-4(5) ethers

Various methods of synthesizing functional derivatives of dithia-13(16)-crown-4(5) ethers are proposed. Complex-formation of the obtained compounds with Ag+ and Pb2+ ions has been studied using 1H NMR. A radiometric method was used to investigate the extracting ability of substituted dithia-13(16)-crown-4(5) ethers in relation to Ag+ and Cd2+ ions from aqueous solution in the presence of anions of various degree of hardness, with determination of the metal content.

Synthesis and extraction properties of oxathiacrown compounds containing benzyl groups

Abstract8-Benzyl-1.4-dioxa-7,10-dithiacyclododecane and 11-benzyl-1,4,7-trioxa-10,13-dithiacyclopentadecane were obtained by the interaction of (2,3-dibromo-1-propyl)benzene with 1,8-dimercapto-3,6-dioxaoctane and 1,11-dimercapto-3,6,9-trioxaundecane. The extracting ability of the obtained compounds has been studied in relation to Sr2+ and Pb2+ ions from aqueous solutions in the presence of anions of various degrees of hardness with determination of the metal content by a radiometric method.

Pseudorotaxane Structures Based on Thiophene-Containing Dibenzo-24-crown-8 Ether Derivatives

Разработан метод получения дибензо-24-краун-8-эфиров (ДБ24К8), содержащих один или два 3,4-диоксиэтилентиофеновых заместителя, с помощью реакции кросс-сочетания по Стилле. Исследование комплексообразования монозамещенного ДБ24К8 с виологеном с использованием спектральных и электрохимических методов подтвердило образование псевдоротаксановой структуры. Строение синтезированных соединений доказано с помощью комплекса физико-химических методов.

Facile transformation of the hydroxy-substituted oxathiacrown ethers

Abstract 9(12)‐Hydroxy‐dithia‐13(16)‐crown‐4(6)‐ethers have been prepared by the condensing an oligoethylene glycol dithiol with 2,3‐dibromo‐1‐propanol. Methods of oxidation, halogenation, amination, and esterification of the 9‐hydroxythiacrown ether, producing corresponding oxathiacrown ether derivatives in good yields, have been developed. Cyclic destruction has not been found in the studied reactions. The change of the oxathiamacrocyclic ring size in the course of the halogenation and amination reactions was revealed.

Addition of dichlorocarbene to tricyclo[4.3.0.03,7]nona-4,8-diene

Addition of dichlorocarbene to tricyclo[4.3.0.03,7]nona-4,8-diene (brexadiene) under conditions of phase transfer catalysis occurs from theexo side. Cyclopropyl-allyl rearrangement of intermediate chlorocyclopropanes yields tricyclo[5.4.0.03,8]undecadienes.