Molecular Recognition and Catalysis: from Macrocyclic Receptors to Molecularly Imprinted Metal Complexes

Abstract

The results of studying a number of reactions catalyzed by several types of soluble macromolecular catalytic systems capable of selectively binding organic substrates, namely, modified cyclodextrins, calixarenes and dendrimers are presented. The use of modified cyclodextrins as components of a catalytic system in the phenol and benzene hydroxylation by hydrogen peroxide allows one both to increase the catalytic activity and to change significantly the chemical selectivity. Phosphorilated calixarene -Rh catalytic systems was found to be catalytically active in hydroformylation of linear alkenes C 7 -C 12 . The results of experiments on the oxidation of C 7 -C 16 alkenes show that, when the ligand is the dendrimer molecule, the fraction of forming methyl ketones substantially increases for the substrates C 7 -C 9 . For the higher alkenes, this effect is not observed.

Supramolecular catalytic systems in biomimetic oxidation

“…The predominant formation of the ortho hydroxylation prod uct is observed at the high conversion of the substrate. 2 The use of the catalytic systems containing β cyclo dextrins in ethylbenzene oxidation provides the acetophe none yields close to quantitative (Table 8). For example, upon ethylbenzene oxidation in the presence of ethoxy ethylated β cyclodextrin and the iron(III) salt for 4 h the yield of acetophenone was higher than 90% and acetophe none remained to be the single reaction product.…”

“…Ethylbenzene oxidation at various concentrations of so dium dodecyl sulfate (1) and CTMAB(2). Y is the yield of acetophenone.…”

Design of supramolecular metal complex catalytic systems for petrochemical and organic synthesis

“…This approach provides wide possibilities for design of new highly active metal com plex catalysts with high substrate, regio , and chemiose lectivity. [1][2][3][4][5][6][7] Various classes of receptor molecules, particularly, cyclodextrins, calixarenes, and dendrimers ( Fig. 1), are used for the design of supramolecular catalysts.…”

“…1), are used for the design of supramolecular catalysts. [2][3][4]8,9 Cyclodextrins are macrocyclic compounds formed by α D glucopyranose. Calixarenes are the compounds syn thesized by the condensation of phenols and aldehydes of diverse structure.…”

“…3 The im printing process proceeds as follows. At the first step a receptor molecule interacts with a template molecule to form a host-guest inclusion complex (Scheme 1).…”