Chiral recognition molecule molecular properties

Stationary phases with specific molecular recognition properties for D,L-enantiomers of peptides have been tailored using the molecular imprinting technique. A template molecule is added to suitable monomer(s), the system is polymerized, and the chiral template molecule is washed out [128]. 

Chirality is a pervasive property of an object, which means that in theory, a single remote asymmetric center in a macromolecule is enough to make the entire molecule chiral and, in principle, even the more distant residue could sense the asymmetry induced by the stereogenic center. On the contrary, experiences maturated by synthetic chemists in the construction of molecular species for enantioselective recognition speak for the necessity of placing the asymmetric units in close contact to allow chiral sensing and discrimination. The latter, in fact, arises from attractive forces and steric interactions that require close contact between the counterparts. On the contrary, magnetic asymmetry is not a direct consequence of weak interactions, but is more a property of the space which surrounds a chiral object. 

The recognition of one molecule out of a crowd of many other molecules requires distinction of certain molecular attributes, such as size, polarity, hydrogen bond pattern, chirality, or other physicochemical properties. If several attributes can be checked simultaneously, recognition becomes more selective. Recognition between an enzyme and a substrate was described first by Emil Fischer as the well-known lock and key principle [2], Molecular recognition between complementary DNA strands [3] or protein ligand interactions [4] is very important for the molecular function of living systems. 

This review is dedicated to the synthesis of water-soluble cryptophanes and of the closely related hemicryptophane derivatives that were developed more recently. The study of their binding properties with different species and some peculiar properties related to their chiral structure are also described. A particular attention is given to xenon-cryptophane complexes since, as above mentioned, these complexes have played a major role in the development of water-soluble cryptophane derivatives. We describe in a concise manner the different approaches, which have been reported in the literature to introduce hydrophilic moieties onto the cryptophane structure. Finally, we report some physical properties of the water-soluble cryptophane complexes. This mainly concerns the study of their binding properties with neutral molecules or charged species. The preparation of enantiopure cryptophanes has also contributed to the development of this field. Indeed, it was stressed that cryptophanes exhibit remarkable chiroptical and binding properties in water [11]. These properties are also described. The last part of this review is devoted to hemicryptophane derivatives, which are closely related to the cryptophane structure and which allow the functionalization of the inner space of the molecular cavity. These show a renewed interest in their applications in chiral recognition and supramolecular catalysis. 

Interface, the air-water, chirality and molecular recognition in monolayers at, 28, 45 Intermediates, reactive, study of, by electrochemical methods, 19, 131 Intermediates, tetrahedral, derived from carboxylic acids, spectroscopic detection and investigation of their properties, 21, 37 Intramolecular reactions, effective molarities for, 17, 183 Intramolecular reactions, of chain molecules, 22, 1... 

Crossley et al. (95JCS(CC)1077) covalently linked two tetraarylporphyrins through the methanodiazocine bridge of TB to prepare well-defined chiral cleft-containing molecules 36 and 37a,b (Figure 8), whose molecular recognition properties could be... 

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