Title:     Unlocking the Mysteries of Chiral Phenomena in Complex Environments: A Multifaceted Chiral Spectroscopic Approac

Time:     2024-05-27 09:00

Lecturer:  Prof. Yunjie Xu

  University of Alberta

Venue:    Room 202, Lecture Hall, Lu-Jiaxi Building

Abstract：

Our research program centers on unraveling mechanisms of chirality recognition, transfer, amplification at the molecular level. To achieve this, we explore chirality-related properties of systems across a spectrum of size regimes, encompassing small chiral molecules to atomically precise metal clusters, nanoparticles, and crystals. Our investigations traverse diverse environments, from the gas phase to solution environments and liquid-liquid interfaces. By emphasizing the interplay among different size scales, we aim to extract new physical insights into these intricate chirality events.

While conducting Raman optical activity (ROA) measurements of several transition metal complexes under near resonance condition, we detected very strong chiral Raman signals of achiral solvents. Our search for possible mechanisms led to the discovery of a new form of chiral Raman spectroscopy called eCP-Raman, which combines electronic circular dichroism and circularly polarized Raman (CP-Raman) into one. Building on this discovery, our recent efforts focused on deciphering the chiral spectral features at the luminesce bands of europium complexes using an ROA instrument, where we uncovered multiple contributions to the observed signals. Finally, I will present vibrational circular dichroism investigations on atomically precise chiral silver clusters where strong exciton couplets were detected. By utilizing simulations of the full metal clusters, we extracted some intriguing structural details of these metal clusters and explored bi-directional chirality transfer events between the chiral ligands and the metal cores.

Bio of Prof. Yunjie Xu：

Yunjie Xu’s research program centers on chirality recognition, transfer, and amplification events in isolated molecular clusters, condensed phases, and at liquid-liquid interfaces. To unravel the molecular-level mechanisms underlying these phenomena, Xu develops and applies new spectroscopic tools, in tandem with theoretical modelling. Her pioneering contributions include quantifying stereospecific non-covalent interactions and untangling co-occurring chiral events linked to resonance conditions, thereby advancing our understanding of chiral forces and the light-matter interactions responsible for intricate chiral phenomena.

Xu is a Chemistry Professor at the University of Alberta and a Tier I Canada Research Chair in Chirality and Chirality Recognition. She has received numerous awards and honors, including the 2019 Gerhard Herzberg Award from Canadian Society for Analytical Sciences and Spectroscopy, the 2022 Ioannes Marcus Marci Medal for outstanding achievements in high resolution molecular spectroscopy, and the 2024 John C. Polanyi Award from Canadian Society for Chemistry. She was elected to the Fellowship of the Royal Society of Canada in 2018.