Stiff, and sticky in the right places: The dramatic influence of preorganizing guest binding sites on the hydrogen bond-directed assembly of rotaxanes
UNSPECIFIED. (2001) Stiff, and sticky in the right places: The dramatic influence of preorganizing guest binding sites on the hydrogen bond-directed assembly of rotaxanes. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 123 (25). pp. 5983-5989. ISSN 0002-7863Full text not available from this repository.
Structural rigidity and the preorganization of thread binding sites are shown to have a major influence on template efficiency in the synthesis of hydrogen bond-assembled rotaxanes. Preorganization is so effective, in fact, that with good hydrogen bond accepters (amides) a "world record" yield of 97% for a rotaxane is obtained. The truly remarkable feature of this efficient template, however, is that it allows even poor hydrogen bond accepters testers) to be used to prepare hydrogen bond-assembled rotaxanes, despite the presence of competing hydrogen bonding groups (anions) which bind the key intermediates at least 10000 x more strongly than single. unorganized, ester groups! The structures of the rotaxanes are established unambiguously in solution by H-1 NMR spectroscopy and in the solid state by X-ray crystallography. As a series they provide unique experimental information regarding the nature of amide-ester hydrogen bonding interactions; in particular they suggest that in CDCl3, amide-ester NH . . .O=C hydrogen bonds are similar to1 kcal mol(-1) weaker than the corresponding amide-amide interactions.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry|
|Journal or Publication Title:||JOURNAL OF THE AMERICAN CHEMICAL SOCIETY|
|Publisher:||AMER CHEMICAL SOC|
|Date:||27 June 2001|
|Number of Pages:||7|
|Page Range:||pp. 5983-5989|
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