Positive Homotropic Allosteric Binding of Benzenediols in a Hydrindacene-Based Exoditopic Receptor:  Cooperativity in Amide Hydrogen Bonding

Abstract

The preparation and complexation properties of a hydrindacene-based exoditopic receptor, that exhibits a positive homotropic allosteric binding process toward benzenediols, are described. The exoditopic receptors form 1:2 complexes with resorcinols, catechol, and 3-hydroxybenzyl alcohol with K2/K1 = 3-33. Both the entropy and the enthalpy terms are important in this allosteric system; the crystallographic studies provide the first clear evidence that the cooperativity in amide hydrogen bonding by polarization contributes to the positive homotropic allosteric binding property.

Molecular Recognition – Allosterism Generated by Weak Host–Guest Interactions in Molecular Rectangles

“…[4] More recently, a carefully designed homoditopic system was found capable of giving high positive allosterism for a variety of guests. [5] Differences of 33:1 between the two constants were reported.…”

Hydrogen‐Bond Cooperativity in Formamide2–Water: A Model for Water‐Mediated Interactions

“…Another point of interest concerning folding is the role that cooperative forces [3,14] of amide hydrogen bonds plays in the stabilization of folded structures such as α-helices or β-turns. [15,16] Cooperativity has been proposed to give contributions form entropy, due to the restrictions of internal motions, as well as from inductive polarization of the amide…”

“…Well stablished structural determination methods beyond the simple conformation identification based on the comparison of the observed and ab initio rotational parameters use data from the spectra of the parent and isotopically substituted species. In order to exploit those methods, the spectra of the monosubstituted species 15 Figure 3 for labeling) were measured. The observation of the 2 H14 spectrum was not possible due to overlapping with other spectra.…”

Dynamic Covalently Bonded Rotaxanes Cross‐Linked by Imine Bonds between the Axle and Ring: Inverse Temperature Dependence of Subunit Mobility

“…[7] The less-bulky carbaldehyde groups at the 2,6-positions preferentially occupy the pseudoaxial positions, and so can work as linkers with the amino groups of macrocycle 7 at opposing sides of the molecular plane. The bromo-terminated dicarbaldehyde axle 5 a and TBSO-terminated axle 5 b were prepared from 1,2,4,5-tetrakis(bromomethyl)benzene (Scheme 2).…”