院士大讲堂
报告题目：Hydrogen Bonding and van der Waals Forces as Architects of Molecular Conformation
报告时间：2026-07-24 09:30
报告人： 徐云洁院士,Professor
University of Alberta, Canada
报告地点：卢嘉锡楼202报告厅
转播地点：翔安校区能源材料大楼3号楼会议室3，漳州校区生化主楼307教室
报告摘要：
Our research explores how non-covalent interactions govern molecular shape and chiroptical response in flexible systems. Because many conformers can coexist in solution, predicting their relative stabilities remains a significant theoretical challenge. This presentation will highlight two examples: glycerol dimers and trimers probed by jet-cooled rotational spectroscopy, and highly flexible Salen ligands and their metal complexes in solution studied by vibrational circular dichroism (VCD). While the first example emphasizes the power of rotational spectroscopy for uncovering intricate hydrogen-bonding networks in OH-rich systems, the second illustrates the limitations of current theoretical approaches in predicting preferred conformers governed primarily by van der Waals interactions in solution.
First, the conformational landscapes of binary and ternary glycerol clusters were explored using broadband rotational spectroscopy supported by quantum chemical calculations.1 Multiple experimentally observed isomers reveal the evolution of three-dimensional hydrogen-bonding networks in these OH-rich systems and provide valuable benchmarks for theoretical predictions. Remarkably, the most stable glycerol clusters exhibit hydrogen-bonding motifs similar to those found in water clusters, offering molecular-level insight into the early stages of glycerol self-aggregation and its miscibility with water.
Second, we show that the seemingly benign CDCl3 solvent profoundly alters the conformational landscape of a flexible Salen ligand while leaving its metal complexes largely unaffected.2,3 This selective solvent effect, invisible to IR spectroscopy but revealed by VCD, arises because weak intra-solute van der Waals interactions are replaced by competing solute–solvent interactions in solution. Microsolvation modeling using Grimme’s quantum cluster growth approach illustrates how this delicate balance reshapes conformational equilibria and highlights the challenges current solvation models face when weak non-covalent interactions compete on comparable energy scales.
报告人简介：
Yunjie Xu earned her BSc in Chemistry and in Applied Mathematics from Xiamen University and a PhD in Physical Chemistry from the University of British Columbia. She is a full professor at the University of Alberta and holds the Tier I Canada Research Chair in Chirality and Chirality Recognition. Xu’s research program focuses on chirality recognition, transfer, and amplification events in isolated molecular clusters, condensed phases, and at liquid-liquid interfaces. Her pioneering contributions include quantifying stereospecific non-covalent interactions and untangling chiral events under resonance conditions, thereby advancing our understanding of chiral forces and the light-matter interactions responsible for intricate chiral phenomena. She has received numerous awards and honors, including the 2019 Gerhard Herzberg Award from Canadian Society for Analytical Sciences and Spectroscopy, the 2024 John C. Polanyi Award from Canadian Society for Chemistry, and 2024-2025 Killam Annual Professorship from the Killam Foundation. In 2018, she was elected to the Fellowship of the Royal Society of Canada, Academy of Science.
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