Vibrational specificity of proton-transfer dynamics in electronically excited 6-hydroxy-2-formylfulvene

Foguel, Lidor

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https://hdl.handle.net/2142/107704 Copy

Description

Title

Vibrational specificity of proton-transfer dynamics in electronically excited 6-hydroxy-2-formylfulvene

Author(s)

Foguel, Lidor

Contributor(s)

• Vaccaro, Patrick
• Vealey, Zachary

Issue Date

2020-06-24

Keyword(s)

Comparing theory and experiment

Abstract

The transduction of protons between distinct donor and acceptor sites, as often directed by attendant hydrogen bonds, is a ubiquitous chemical transformation essential for all of acid/base chemistry, yet the role of selective nuclear displacements in this deceptively simple process remains a topic of active investigation. Polarization-resolved degenerate four-wave mixing (DFWM) spectroscopy was employed to investigate the vibrational specificity of proton-transfer dynamics in the lowest-lying singlet excited state, \textit{\~{A}}$^{1}$B$_{2}$ ($\pi$$^{*}$$\pi$), of 6-hydroxy-2-formylfulvene (HFF), with judicious selection of incident and detected polarization geometries allowing for the quantitative extraction of refined rotation-tunneling parameters. While the zero-point level of the ground electronic state [\textit{\~{X}}$^{1}$A$_{1}$] straddles the barrier crest for hydron migration and thus affords a prototypical example of low-barrier hydrogen bonding,\footnote{Z. N. Vealey, L. Foguel and P. H. Vaccaro, \textit{J. Phys. Chem. Lett.} \textbf{9}, 4949 (2018).} this model system also has been found to undergo a dramatic change in dynamics upon $\pi$$^{*}$$\leftarrow$ $\pi$ electron promotion – as reflected by a $>$1000-fold decrease in tunneling rates.\footnote{Z. N. Vealey, L. Foguel and P. H. Vaccaro, \textit{J. Phys. Chem. A.} \textbf{123}, 6506 (2019).} This talk will present complementary experimental and computational analyses of vibronic levels in the pertinent \textit{\~{A}}$^{1}$B$_{2}$ ($\pi$$^{*}$$\pi$) manifold designed to unravel the dependence of unimolecular reactivity on heavy atom motion and to elucidate the disparate behavior observed for analogous \textit{\~{X}}$^{1}$A$_{1}$ features.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

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http://hdl.handle.net/2142/107704

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Copyright 2020 is held by the Author(s)

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