Influence of remote intramolecular hydrogen bonds on the thermodynamics of molecular recognition of cis-1,3,5-cyclohexanetricarboxylic acid.

Variable temperature binding studies and isothermal titration microcalorimetry were used to probe the thermodynamics of molecular recognition of cis-1,3,5-cyclohexanetricarboxylic acid by tripodal hosts. Remote intramolecular hydrogen bonds, used to restrict conformationally one of the hosts, exhibit a strong influence on the thermodynamic functions for the binding process Delta H and Delta S, with little effect on Delta G. This suggests that the conformational lock imposed by the intramolecular hydrogen bonds organizes the receptor in a conformation that is not optimal for the binding of the triacid. (C) 1998 Elsevier Science Ltd. All rights reserved.