Pinning Down Small Populations of Photoinduced Intermediates Using Transient Absorption Spectroscopy and Time-Dependent Density Functional Theory Difference Spectra to Provide Mechanistic Insight into Controlling Pyridine Azo Dynamics with Protons
Year: 2024
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide In this work, the impact of protonation on the photoisomerization ( trans → cis ) and reversion ( cis → trans ) of three pyridine-based azo dyes ( PyrN ) is investigated by using a combination of transient absorption spectroscopy and time-dependent density functional theory computed difference spectra. The photophysical behaviors of the PyrN dyes are altered by the addition of one or two protons. Protonation of basic pyridine nitrogens results in an ultrafast accelerated reversion mechanism after photoisomerization, while protonation of azo bond nitrogens restricts cis isomer formation entirely. Computed difference spectra provide spectral signatures that are critical for the assignment of low-population long-lived states, providing direct evidence of the accelerated reversion mechanism. Thus, the addition of organic acids can selectively control the photophysics of azo dyes for a wide range of applications, including materials design and pharmaceuticals.
Institution: Lehigh University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
Awards: MRI: Acquisition of Transient Absorption Spectrometer for Multidisciplinary Research in Chemistry, Materials Science and Solar Energy Conversion, G1641338816, Track 4: Advanced CI Coordination Ecosystem: Monitoring and Measurement Services, Track 1: ACCESS Resource Allocations Marketplace and Platform Services (RAMPS), ACO: An Open CI Ecosystem to Advance Scientific Discovery (OpenCI), Track 3: COre National Ecosystem for CyberinfrasTructure (CONECT), CC* Compute: Acquisition of a Lehigh University HPC cluster to enhance collaboration, research productivity and educational impact, Track 2: Customized Multi-tier Assistance, Training, and Computational Help (MATCH) for End User ACCESS to CI, MRI: Upgrade of a 500 MHz Nuclear Magnetic Resonance (NMR) Spectrometer
OpenAlex ID: W4402504293