Molecular recognition templates

Keywords. Imprinting, Colloids, Microgels, Molecular Recognition, Templates... 

Fig. 7. General scheme for the preparation of molecularly imprinted nanospheres and their use for molecular recognition. Template molecules induce the formation of binding sites during the miniemulsion polymerization. The templates are extracted from the highly crosslinked particles and are molecularly recognized by the nanospheres selective binding sites...

In an example of molecular recognition templated by Pt, the tris-guanine Pt (NH3)] cation includes a head-to-head arrangement of two NT-coordinated manines, the Watson-Crick faces of which are available to interact with a second tris-guanine Pt (NH3)] cation via several hydrogen-bonding interactions. " ... 

Apart from the successful imprinting discussed above, the recognition for many templates is far from that is required for the particular application, even after careful optimization of the other factors affecting the molecular recognition properties. Often, a large excess of MAA in the synthesis step is required for recognition to be observed and then only in solvents of low to medium polarity and hydrogen bond... 

Fig. 1. Preparation of configurational biomimetic imprinted networks for molecular recognition of biological substrates. A Solution mixture of template, functional monomer(s) (triangles and circles), crosslinking monomer, solvent, and initiator (I). B The prepolymerization complex is formed via covalent or noncovalent chemistry. C The formation of the network. D Wash step where original template is removed. E Rebinding of template. F In less crosslinked systems, movement of the macromolecular chains will produce areas of differing affinity and specificity (filled molecule is isomer of template).

To prepare artificial enzymatic systems possessing molecular recognition ability for particular molecules, molecular imprinting methods that create template-shaped cavities with the memory of the template molecules in polymer matrices, have been developed [22, 30-35] and established in receptor, chromatographical separations, fine-chemical sensing, etc. in the past decade. The molecular... 

Chemical templates are being increasingly employed for the development of dynamic combinatorial libraries (DCL) [94-98]. These (virtual) libraries of compounds are produced from all the possible combinations of a set of basic components that can reversibly react with each other with the consequent potential to generate a large pool of compounds. Because of the dynamic equilibria established in a DCL, the stabilization of any given compound by molecular recognition will amplify its formation. Hence the addition of a template to the library usually leads to the isolation of the compound that forms the thermodynamically more stable host-guest complex (see Scheme 37). 

In addition to imprinted acid-base catalysts [49-55], attempts to imprint metal complexes have been reported and constitute the current state of the art [46, 47]. In most cases of metal-complex imprinting, ligands of the complexes are used as template molecules, which aims to create a cavity near the metal site. Molecular imprinting of metal complexes exhibits several notable features (i) attachment of metal complex on robust supports (ii) surrounding of the metal complex by polymer matrix and (iii) production of a shape selective cavity on the metal site. Metal complexes thus imprinted have been appHed to molecular recognition [56, 57], reactive complex stabilization [58, 59], Hgand exchange reaction [60] and catalysis [61-70]. 

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]. 

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