SUPRAMOLECULAR NANOSIZED SYSTEMS BASED ON THE PHOTOSENSTIVE CROWN-ETHER DERIVATIVES FOR SENSORING APPLICATIONS
Zaitsev S. Yu., Tsarkova M. S.,Solovieva D. O., Zaitsev I. S.
FGOY VPO MSAVM&B, Acad. Skryabina Str. 23, Moscow 109472, Russia,
The synthesis and monolayer study of various crown-ethers with particular photosensitive and self-assembly fragments in the molecule is a quickly growing field of modern research “at the junction” of chemistry, physics, ecology, biology, nanotechnology, etc. Mono- and multilayer films based on these polyfunctional molecules are important not only for modeling of molecular recognition and ion transport processes in biomembranes, but also for the design of ion-selective optonanomaterials [1-4].
The amphiphilic photosensitive benzodithia-15(18)-crown-5(6)-ethers have been synthesized in the Photochemistry Center RAS and its surface-active, ionoselective and photosensitive properties in solutions and at the interfaces have been investigated. These crown-ethers formed stable insoluble monolayers on distilled water (collapse pressure about 35 mN/m) and aqueous solutions containing alkali (38 mN/m) and heavy metal cations (collapse pressures 33 and 31 mN/m for Ag+ and Hg2+ respectively). The existence of two different types of the crown-cation complexes, depending on the presence of alkali or heavy metal cations in the subphase has been found for the first time. It was shown by measurements of the surface pressure - and surface potential - area per molecule isotherms that heavy metal cations from the subphase penetrate into the dithiacrown-ether ring and this crown-cation complex is additionally stabilized by the anionic sulfonate group of this molecule. In contrast, alkali and alkali-earth metal cations strongly interact with the negatively charged sulfonate group without penetration into the dithiacrown-ether ring. These conclusions have been confirmed by Brewster angle microscopy and by reflection intensity measurements on water and various aqueous salt subphases. The kinetics of the spectral reflection intensity changes under illumination of the crown-ether monolayer on aqueous and different salt subphases gives additional information about crown-cation interactions. Irreversible changes of the spectral reflection intensity of the crown-ether monolayers have been observed on all studied subphases. These irreversible changes of the spectral reflection intensity are, probably, due to “cyclobutane ring” formation by interaction of the C=C bonds of neighbouring crown-ether molecules. Only the use of special polymer matrixes leads to the reversible changes of the spectral reflection intensity of mixed crown-ether monolayers in the presence of heavy metal cations in the subphase that is very important for design of the sensoring materials.
Thus, the supramolecular nanosized systems based on amphiphilic photosensitive benzodithia-crown-ethers have been prepared and investigated. This approach is promising for construction of nanomaterials with desirable properties.
The author is thankful to his coworkers in the FGOY VPO MSAVM&B (Moscow, Russia) for technical assistance, prof. Gromov C. P. and coworkers in the Photochemistry Center RAS (Moscow, Russia) for the sample preparations, prof. ShtyrlinV.G. and coworkers in the Kazan (Volga Region) Federal University (Kazan, Russia) for the molecular model study, prof. Möbius D. (Max-Plank Institute of Biophysical Chemistry, Göttingen, Germany) for valuable discussions.
This work has been supported by grants of the Russian Foundation of Basic Research (14-03-00154_a, 14-03-07008-d).
References
Tsarkova M.S., Zaitsev S.Yu., Zaitsev I.S., Krutikov A.A., ShtyrlinV.G. Macroheterocycles 2014 in press.
Zaitsev S.Yu., Zarudnaya E.N., Zaitsev I.S., Tsarkova M.S., Lobova N.A., Vedernikov A.I., Gromov S.P. Colloids and Surfaces A: Physicochem. Eng. Aspects, 2011, 383, 120–124.
Zaitsev S. Yu. Supramolecular nanodimentional systems at the interfaces: concepts and perspectives for bio nanotechnology. Moscow:LENAND, 2010, 208 p. (Russian).
Zaitsev S. Yu. Russian nanotechnologies, 2009, v.4, N.7-8, 6-18 (Russian).
Ushakov E. N., Alfimov M. V., Gromov S. P. Uspechi Chimii, 2008, V.77, P.39-59 (Russian).
Zaitsev S. Yu.; Zarudnaya E. N.; Möbius D.; Bondarenko V. V.; Maksimov V. I.; Zaitsev I. S.; Ushakov E. N.; Lobova N. A.; Vedernikov A. I.; Gromov S. P.; Alfimov M. V. Mendeleev Commun. 2008, v.18, 270-272.