Reaction Control by Molecular Recognition – A Survey from the Photochemical Perspective

Abstract

Molecular recognition through non -covalent interactions between two or more molecules has attracted much attention from a broad spectrum of chemists for a long period of time and has already found many applications in various areas of science and technology. The concept of molecular recognition was fi rst developed for biomolecular systems such as enzyme, antibody and DNA, which can selectively bind the specifi c target molecules through non -covalent weak interactions, including hydrogen bonding, van der Waals, dipole -dipole, charge -dipole and hydrophobic interactions. 1 -3 Recent studies on artifi cial host -guest systems have revealed that molecular recognition is the essential conceptual basis for supramolecular chemistry and nanotechnology. 4,5 Reaction control through complexation of substrate by supramolecular host is a relatively new idea compared to the conventional approaches that involve simple collisional attack or coordination of substrate to metal. Multiple non -covalent interactions in supramolecular assembly bind and locate a site -specifi c substrate in the right position, orientation and conformation near the catalyst or active site, stabilize the high -energy transition state, and eventually make the reaction faster and more selective. Typical examples are found in enzymatic reactions, which proceed with high specifi city and effi ciency in aqueous solutions under mild conditions. These observations in natural systems have inspired Molecular Encapsulation: Organic Reactions in Constrained SystemsEdited by Udo H. Brinker and Jean-Luc Mieusset