Abstract：
Supramolecular mechanophores typically exhibit much lower mechanical strengths than covalent counterparts, with strengths usually around 100 pN, which is significantly lower than the nN-scale strength of covalent bonds. Inspired by the slow dissociation kinetics of the cucurbit[7]uril (CB[7])-hexanoate-isoquinoline (HIQ) complex, we discovered that charge-dipole repulsion can be utilized to create strong supramolecular mechanophores. When activated at its -COO- state, the CB[7]-HIQ complex exhibits a high mechanical strength of ~700 pN, comparable to weak covalent bonds such as Au-S bonds or thiol-maleimide adducts. The strength of the CB[7]-HIQ complex can also be tuned with pH in a gradual manner, with a minimum value of ~150 pN at its -COOH state, similar to an ordinary supramolecular conjugate. This research may pave the way for the development of supramolecular architectures that combine the advantages of covalent and supramolecular systems.
摘要：
超分子力学团通常表现出比共价对应物低得多的机械强度，强度通常在100pN左右，显著低于共价键的nN尺度强度。受葫芦[7]脲（CB[7]）-己酸-异喹啉（HIQ）复合物的缓慢解离动力学的启发，我们发现电荷-偶极排斥可以用来产生强大的超分子动力团。在其-COO-状态下激活时，CB[7]-HIQ复合物具有〜700pN的高机械强度，与弱共价键如Au-S键或硫醇-马来酰亚胺加合物相当。CB[7]-HIQ复合物的强度也可以通过pH逐渐调节，在其-COOH状态下的最小值为〜150pN，类似于普通的超分子共轭物。这项研究可能会为结合共价和超分子系统优点的超分子结构的发展铺平道路。
