АННОТАЦИЯ
It was shown by 1H NMR spectroscopy that symmetrical bis(crown)stilbenes (L) and small alkali and alkaline-earth metal cations form 1(L):1(Mm+) and 1(L):2(Mm+) complexes in MeCN solutions. In the case of large or hydrated metal cations such as Cs+, Rb +, K+, Ba2+, Sr2+, [Ca(H 2O)x]2+ and stilbenes with a small crown-ether cavity as compared with the metal cation size, stable bis-sandwich complexes 2(L):2(Mm+) can also be formed. A stable bis-pseudosandwich 2:2 complex is also produced from bis(18-crown-6)stilbene with the propanediammonium ion. The effect of the crown-ether size and the cation size and nature on the route of stilbene phototransformation and product composition was elucidated. The bis-(pseudo)sandwich complexes undergo effective stereoselective [2+2] photocycloaddition giving mainly rctt isomers of new 1,2,3,4-tetracrown cyclobutanes. The structures of complexes of bis(crown)stilbenes and obtained cyclobutanes were confirmed by X-ray diffraction. © 2011 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
ЦИТАТА
Controlled self-assembly of bis(crown)stilbenes into unusual bis-sandwich complexes: Structure and stereoselective [2+2] photocycloaddition / S.P. Gromov, A.I. Vedernikov, N.A. Lobova, M.V. Alfimov, L.G. Kuz'Mina, S.S. Basok, Y.A. Strelenko, J.A.K. Howard // New Journal of Chemistry. – 2011. – Т. 35. – № 3. – P. 724-737
