Talk on host-guest chemistry in water by Prof. Kang Cai (Nankai University)

On September 1, 2025, Prof. Kang Cai of Nankai University was invited to our university to serve as a thesis defense committee member. During his visit, he kindly delivered an insightful academic lecture for our group.

Dr. Cai received both his bachelor’s and doctoral degrees from Peking University, where he completed his Ph.D. under the supervision of Professor Da-hui Zhao. He then moved to Northwestern University (USA) for postdoctoral research, working with the distinguished chemist J. Fraser Stoddart. Dr. Cai returned to China in 2021 and has been on the faculty at Nankai University since then. After returning, he has engaged in close collaborations with multiple research groups and has focused predominantly on high-affinity aqueous recognition and related functional applications.

In his lecture, Dr. Cai first provided a systematic overview of the current state and key challenges of aqueous molecular recognition systems. Building on that background, he described in detail how his team translated theoretical design concepts into practice, overcame synthetic difficulties, and successfully constructed, via a modular strategy, a new class of chiral deep-cavity macrocycles. These macrocycles exhibit extremely high affinities toward a variety of guest molecules in water, and their binding of steroidal compounds in particular reaches what the team reports as the highest level known to date. In addition, the macrocycles offer convenient sites for modification, intrinsic fluorescence, and a defined chiral environment, all of which make them attractive platforms for molecular recognition and materials construction. Leveraging the high-affinity nature of these macrocycles, Dr. Cai’s group has developed a range of applications, including drug antagonism, fluorescence sensing, molecular detection, and high-strength hydrogels, demonstrating the translational potential from recognition chemistry to functional materials. At the close of his talk, Dr. Cai also shared the team’s recent work probing the macrocycles’ photophysical and magnetic properties, with a particular emphasis on studies of high-spin multiradical states.

As peers in the field of molecular recognition and self-assembly, we have long held each other in mutual esteem. Taking advantage of this visit, faculty, students, and guests engaged in sustained and in-depth discussions with him on the macrocycles’ synthetic strategies, the thermodynamic and kinetic mechanisms of molecular recognition, and potential applications in biological systems and hydrogel materials. The exchange broadened perspectives and deepened our collective understanding of aqueous recognition systems.

（Drafted by Zhaolin Zhu，reviewed by Yibin）