Efficient Modulation of Hydrogen-Bonding Interactions by Remote Substituents
摘要:
[GRAPHICS]A series of tetralactam macrocycles having different substituents were prepared, and their binding affinities for an adipamide guest were investigated in CDCl(3) by (1)H NMR titrations. The association constants strongly depend on the substituents, varying up to DeltaDeltaG = 3.4 kcal/mol; electron-donating substituents (OMe, NMe(2)) decrease the binding affinity, while electron-withdrawing groups (Cl, NO(2)) increase it. These large substituent effects have been rationalized by secondary repulsions and partial perturbations of intramolecular hydrogen bonds.
作者:Fiona J. Carver、Christopher A. Hunter、Richard J. Shannon
DOI:10.1039/c39940001277
日期:——
Macrocyclic hosts are prepared in 80–90% yields by using intramolecular hydrogen-bonding interactions to direct the cyclisation; in the absence of such effects, intermolecular hydrogen-bonding interactions template the formation of catenanes.