ИСТИНА

Synthesis of the new styryl dyes 1 containing a crown-ether fragment and a terminal NH3+ group in the N-substituent of heterocyclic residue was elaborated. It was found that dyes 1 can spontaneously form dimers 2 in both the solid state and in solution (MeCN, CH2Cl2) due to the intermolecular binding of NH3+ group with crown-ether moiety. The dimers have a head-to-tail pseudocyclic structure. The dimerization equilibrium constants for dyes 1 were estimated by 1H NMR titration in MeCN-d3 (logKd up to 8.0). Visible light irradiation of dimers 2 in solution, thin polycrystalline films and monocrystals induced stereospecific [2+2] photocycloaddition reaction generating cyclobutane derivatives 3 as the single rctt isomer. The photocycloaddition quantum yield was varied between 0 and 0.38, depending on the nature of heterocyclic residue, the length of ammonioalkyl substituent and the type and size of crown-ether fragment in dyes 1. The structures of 1 3 were studied by X-ray diffraction and NMR spectroscopy. Dyes 1 can be utilized in systems of optical registration and storage of information. This work was financially supported by the Russian Scientific Foundation (14-13-00076) and the Russian Academy of Sciences. [1] Gromov S.P., Vedernikov A.I., Lobova N.A., Kuz’mina L.G., Dmitrieva S.N., Strelenko Yu.A., Howard J. A.K., J. Org. Chem., 2014, 79, 11416. [2] Ushakov E.N., Vedernikov A.I., Lobova N.A., Dmirtieva S.N., Kuz’mina L.G., Moiseeva A.A., Howard J.A.K., Alfimov M.V., Gromov S.P., J. Phys. Chem. A., 2015, 119, 13025.