Chemistry and Catalysis in Functional Cavitands

Abstract

Summary Biological macromolecules use binding forces to access unfavorable chemical equilibria and stabilize reactive intermediates by temporarily isolating them from the surrounding medium. Certain synthetic receptors, functional cavitands, share these abilities and allow the direct observation of labile intermediates by conventional spectroscopy. The cavitands feature inwardly-directed functional groups that form reversible, covalent bonds with small molecules held inside. Tetrahedral intermediates of carbonyl addition reactions – hemiaminals, hemiacetals and hemiketals – show amplified concentrations and lifetimes of minutes under ambient conditions. Labile intermediates in addition reactions of carboxylic acids to isonitriles are also stabilized by isolation in the space of the cavitands. The restricted environments channel the reactions of intermediates in cavitands along a specific path, and strengthen the parallels between functional synthetic cavitands and enzymes.

Investigation into Drug Solubilisation Potential of Sulfonated Calix[4]Resorcinarenes

“…However, since resorcinol will react with a wide range of aldehydes under the conditions required for their synthesis, an extensive library of structurally diverse calix[4]resorcinarenes exists. The calix [4]resorcinarenes have found widespread use in host-guest and supramolecular chemistry, exemplified in the synthesis of cavitands and carceplexes [7,8]. They have been demonstrated to form stable complexes with small molecular species but notably the majority of these studies have been undertaken in non-polar media -which would not be suitable for drug delivery applications.…”

Exclusive recognition of sarcosine in water and urine by a cavitand-functionalized silicon surface

“…Cavitands, defined as concave organic molecules capable of molecular recognition (5), are particularly versatile synthetic receptors, whose complexation properties depend on size, shape, and functionality of the preorganized cavity (6)(7)(8). Among them, tetraphosphonate cavitands are outstanding: Their complexation ability spans from positively charged inorganic and organic species (9) to neutral molecules (10).…”

Synthesis and Electrochemical Properties of the Tetraferrocenyl‐Cavitand in Dimethyl Formamide Solvent Using Platinum and Carbon Working Electrodes

“…The cavitands are also host molecules with special shape and functional groups that can bind usually smaller size different guest molecules [5][6][7]. They have been used in sensors as selective molecular recognizing agents [8,9].…”