Molecular recognition studies

A series of model siderophore molecular recognition studies coupled with host-guest carrier facilitated model membrane transport studies was reported (198-202). Three approaches were taken which incorporate (i) second coordination shell host-guest complexation, (ii) ternary complex formation, and (iii) a combination of ternary complex - second coordination shell host-guest complex formation. Examples of these approaches are described below. 

Similarly, Lehn and co-workers reported the Stille coupling of stannane 91 with bromoanthracene 92 to provide aminopyrimidine 93 after deprotection <00T6701>. These 2-aminopyrimidines were utilized in molecular recognition studies. 

Figure 7.1.4. The scheme of formation of [2.2.2]cryptand. marked the start of molecular recognition studies. As described in Chapters 2 and 3, the Pedersen analysis was later extended by Lehn s studies of the complementarity of sizes and shapes ofthe cryptand cavities and their guests, and by Cram s preorganization studies. In general, crown ethers and cryptands exhibit analogous complexation behaviour. Thus, similarly to the former host molecules, cryptands in the free, uncomplexed state elongate the vacant cavity by rotating a methylene group inward. Thus, the N...N distance in [2.2.2]-cryptand 54 across the cavity is extended to almost 70 pm [18] whilst, in the complexed...

Liu, Y. Li, L. and Chen, Y. (2002) Molecular Recognition Studies on Supramolecular Systems. Part 38. Inclusion Complexation of Organic Dyes by Organoselenium Bridged Bis-(/f-cyclodextrin)s with a Short linker,/. Incl. Phenom. 42, 151-155. 

Molecular recognition studies are typically carried out in solution, and the effects of intermolecular interactions are often probed by spectroscopic methods. 

Fish RH, Jaouen G (2003) Bioorganometallic chemistry structural diversity of organometallic complexes with bioligands and molecular recognition studies of several supramolecu-lar hosts with biomolecules, alkali-metal ions, and organometallic pharmaceuticals. Organometallics 22 2166-2177... 

Clavier et al. used the amino acid (L)-valine to synthesise a C-chiral imdazolidinium salt for chiral molecular recognition studies [65]. The synthetic route utilises the C-terminus to form an amide. Subsequent reduction to the diamine and ring closure with trimethyl-orthoformate yields the chiral imdazolidinium salt (see Figure 6.25). 

Gale, P.A. (2006) Structural and molecular recognition studies with acyclic anion receptors. Accounts of Chemical Research, 39, 465-475. 

Bach, T. The Patemo-Buchi reaction of N-acyl enamines and aldehydes - the development of a new synthetic method and its application to total synthesis and molecular recognition studies. SynlettZOOO, 1699-1707. 

Another popular host for molecular recognition studies in monolayers is thiol-derivatized cyclodextrin. Kaifer and coworkers have prepared monolayers from fi-cyclodextrin 19 in which all primary hydroxyls are replaced by SH groups. This compound can form up to seven gold-sulphur chemical bonds on the surface. These monolayers are incomplete to cover the gold surface completely, they were treated successively with ferrocene (to block the cyclodextrin cavities) and pentanethiol (to fill in the spaces between cavities). Cyclic voltammetry showed that the layers obtained bind ferrocene. Ferrocene trapped in the cyclodextrin cavities can be replaced by another known guest, electroinactive m-toluic acid444. 

Dufrene, Y. F. and Hinterdorfer, P. 2008. Recent progress in AFM molecular recognition studies,... 

Liu. Y. Han, B.H. Qi, A.D. Chen, R.T. Molecular recognition study of a supramolecular system. 11. Chiial recognition of aliphatic amino acids by natural and modified a-cyclodextrins in acidic aqueous solution. Bioorg. Chem. 1997. 25 (3), 155-162. 

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