ORCID
https://orcid.org/0000-0002-9391-4332
Date of Award
10-19-2023
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
Proton-coupled electron transfer (PCET) is a vital process in chemical and biochemical catalysis, and it has attracted broad interest in mechanistic studies. Current research efforts, however, have focused on the electron transfer side of this process and are carried out in solution-phase systems. A series of model complexes that mimic the PCET reaction center of Tyr−His pair in Photosystem II were first synthesized and characterized in the ground-electronic state with cryogenic-ion vibrational spectroscopy (CIVS). Each model showed signatures of strong intramolecular hydrogen bonds between the PCET donor and acceptor motifs, resulting in very red shifted and diffuse OH stretch transitions. A computational model that couples the shared proton to the other vibrational normal modes reproduced the CIVS spectral lineshapes qualitatively well and predicted very soft and anharmonic potential energy surfaces. Then, this dissertation will introduce the principles and development process of multidimensional time-resolved CIVS, a novel experimental method that concurrently possesses the advantages of CIVS and 2D IR, which can capture ultrafast chemical dynamics in the gas phase and reveal correlation of vibrational modes and their evolution by presence of cross-peaks. Linear TR-CIVS by interferometry of an ultrafast infrared pulse pair on protonated diglycine was first performed to prove the feasibility of CIVS studies with ultrafast lasers. The first nonlinear transient absorption CIVS was then demonstrated on a rhenium carbonyl compound. The establishment of ultrafast CIVS will unwrap innovative directions of spectroscopic research for chemically and energetically well-defined gas phase systems.
Language
English (en)
Chair and Committee
Joseph Fournier
Committee Members
Richard Mabbs
Recommended Citation
Chen, Liangyi, "Unraveling Vibrational Spectral Signatures of Strongly Hydrogen-Bonded Protons via Development of Novel Gas-Phase Ultrafast Spectroscopic Methods" (2023). Arts & Sciences Electronic Theses and Dissertations. 3181.
https://openscholarship.wustl.edu/art_sci_etds/3181