Vladimir Azov   Postdoctoral Fellow Location: HCI G-322 Phone: +41-1-633 4515 e-mail:

Synthesis and conformational switching studies of partially and differentially bridged resorcin[4]arene cavitands. Methods for preparation of partially bridged resorcin[4]arene cavitands (R = n-C6H13) from resocin[4]arene were developed. Several different asymmetric cavitands with one or two substituents (R`) attached to the upper rim were prepared. This synthetic route can be used for formation of other modified cavitands bearing specific functional groups, for example, dye labels for spectroscopic studies or guest recognition centers for selective guest binding.

Detailed investigation of conformational switching between the vase and the kite conformers of cavitands was performed by means of NMR spectroscopy upon (a) temperature variations, (b) protonation.

• The thermodynamic and kinetic parameters for the vase-kite1-kite2interconversions were determined by variable-temperature NMR and lineshape fitting • Strong solvent dependence of both temperature- and pH-triggered vase -> kite switching was discovered • Modified cavitands (asymmetrically substituted as well as partially-bridged 'cleft' intermediates) displayed reversible temperature- and pH-triggered vase kite switching Development of the methodology towards cavitands with long modular "arms":

The aim of the project is the development of efficient routes for the synthesis of differentially-bridged cavitands with long arms composed of p-phenylene and ethyne building blocks. Sonogashira or Suzuki couplings are used for modular "arm" construction and allow flexible variation in spacer length. Further studies will be aimed on stepwise couplings to construct structures with R1 unequal to R2. This methodology will provide access to a variety of functional architectures.

Publications C. Thilgen, V. A. Azov, “Cyclophanes: Definition and Scope”, in Encyclopedia of Supramolecular Chemistry, J. Steed and J. Atwood, eds.; Marcel Dekker, Inc.; NY; 2004, 87, 449-462. V. A. Azov, B. Jaun, F. Diederich, Helv. Chim. Acta 2004, 43, 4759-4763. NMR Investigations into the Vase-kite Conformational Switching of Resorcin[4]arene Cavitands. V. A. Azov, P. J. Skinner, Y. Yamakoshi, P. Seiler, V. Gramlich, F.Diederich “Functionalized and Partially or Differentially Bridged Resorcin[4]arene Cavitands: Synthesis and Solid-state Structures” Helv. Chim. Acta, 2003, 86, 3648-3670. V. A. Azov, F. Diederich, Y. Lill, B. Hecht “Synthesis and Conformational Switching of Partially and Differentially Bridged Resorcin[4]arenes Bearing Fluorescent Dye Labels” Helv. Chim. Acta 2003, 86, 2149-2155. F. M. Menger V. A. Azov “Synthesis and Properties Water-Soluble Asterisk Molecules” J. Am. Chem. Soc. 2002, 124, 11159-11156. F. M.Menger, J. Bian, and V. A. Azov “A 1,3,5-Triaxial-Triamino-Cyclohexane: The Triamine Corresponding to Kemp’s Triacid” Angew. Chem. Int. Ed. 2002, 41, 2581-2584. Alexander A. Yaroslavov, Oleg Yu. Udalykh, Nickolay S. Melik-Nubarov, Viktor A. Kabanov, Yuri A. Ermakov, Vladimir A. Azov and Fredric M. Menger “Conventional and Gemini Surfactants Embedded within Bilayer Membranes: Contrasting Behavior” Chem. Eur. J. 2001, 7, 4835-4843. Fredric M. Menger and Vladimir A. Azov “Cytomimetic Modeling in Which One Phospholipid Liposome Chemically Attacks Another” J. Am. Chem. Soc. 2000, 122, 6492-6493. F. M. Menger, J. S. Keiper, and V. Azov “Gemini Surfactants with Acetylenic Spacers” Langmuir 2000, 16, 2062-2067. Vladimir S. Borodkin, Natalja A. Shpiro, Vladimir A. Azov, and Nikolay K. Kochetkov “Substrate Dependent Intramolecular Pauson-Khand Reaction of Carbohydrate exo-Methylene Derivatives. Unexpected formation of fused “[4.1.0] bicycloheptene – pyranose” tricyclic product” Tetrahedron Lett. 1996, 37, 1489-1492.