英国剑桥大学Christopher A. Hunter团队报道了涉及苯酚-苯酚相互作用的三组分氢键网络协同性的取代基影响。相关研究成果发表在2024年12月18日出版的《美国化学会杂志》。

网络中氢键相互作用之间的协同作用是分子系统中溶剂化和自组装的一个基本方面。一系列双酚（在两个羟基之间形成分子内氢键）与奎宁环的相互作用，用于量化三组分网络中的协同性。通过使用溶液中的¹H NMR光谱和固态中的X射线晶体学，研究确定了双酚中分子内氢键的存在。研究人员使用UV-vis和¹H NMR滴定研究了与奎宁环的相互作用，结果表明分子内氢键在1:1的配合物中持续存在。

通过改变其中一个酚基团上的取代基，可以测量改变羟基之间的分子内氢键强度对奎宁环分子间氢键强度的影响。两种相互作用之间观察到强烈的正协同作用，结合自由能增加高达16 kJ mol^–1。通过改变另一个酚基上的取代基，在复合物中形成分子内氢键和分子间氢键，可以测量这个中心羟基的性质如何调节，与其他两个官能团相互作用之间的协同性。改变这种苯酚的极性对测量的协同性没有影响。

结果表明，氢键网络中的协同性可以理解为两个远程官能团之间的极性相互作用，该相互作用受到中心官能团的阻尼。阻尼的程度由协同性参数κ来量化，对于羟基来说，协同性参数为0.33，这似乎是官能团的几何形状或极化率的内在特性，而不是极性。

附：英文原文

Title: Substituent Effects on Cooperativity in Three-Component H-Bond Networks Involving Phenol–Phenol Interactions

Author: Lucia Trevisan, Andrew D. Bond, Christopher A. Hunter

Issue&Volume: December 18, 2024

Abstract: Cooperativity between H-bonding interactions in networks is a fundamental aspect of solvation and self-assembly in molecular systems. The interaction of a series of bisphenols, which make an intramolecular H-bond between the two hydroxyl groups, and quinuclidine was used to quantify cooperativity in three-component networks. The presence of the intramolecular H-bond in the bisphenols was established by using 1H NMR spectroscopy in solution and X-ray crystallography in the solid state. The interactions with quinuclidine were investigated using UV–vis and 1H NMR titrations, which show that the intramolecular hydrogen bonds persist in the 1:1 complexes. By varying substituents on one of the phenol groups, it was possible to measure the effect of changing the strength of the intramolecular H-bond between the hydroxyl groups on the strength of the intermolecular H-bond with quinuclidine. Strong positive cooperativity was observed between the two interactions, with increases in binding free energy of up to 16 kJ mol–1. By varying substituents on the other phenol group, which makes both an intramolecular H-bond and an intermolecular H-bond in the complex, it was possible to measure how the properties of this central hydroxyl group modulate cooperativity between the interactions with the other two functional groups. Changing the polarity of this phenol had no effect on the measured cooperativity. The results indicate that cooperativity in H-bond networks can be understood as a polar interaction between two remote functional groups that is damped by a central functional group. The extent of damping is quantified by cooperativity parameter κ, which is 0.33 for the hydroxyl group and appears to be an intrinsic property of the geometry or polarizability of the functional group rather than polarity.

DOI: 10.1021/jacs.4c15767

Source: https://pubs.acs.org/doi/full/10.1021/jacs.4c15767