The flavin cofactor performs many functions in the cell based on the ability of the isoalloxazine ring to undergo one- or two-electron reduction and form covalent adducts with reactants such as amino acids. In addition, the strong visible absorption of the cofactor is also the basis for flavin-dependent photoreceptors. Vibrational spectroscopy is uniquely suited to studying the mechanism of flavoproteins since the frequency of the vibrational modes is very sensitive to the electronic structure and environment of the isoalloxazine ring. This chapter describes the mechanistic information that can be gained using vibrational spectroscopy as well experimental challenges and approaches that are used to obtain and interpret the complex data contained in a vibrational spectrum.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/bs.mie.2019.03.011 | DOI Listing |
J Chem Phys
January 2025
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA.
Time-resolved spectroscopy is an important tool for probing photochemically induced nonequilibrium dynamics and energy transfer. Herein, a method is developed for the ab initio simulation of vibronic spectra and dynamical processes. This framework utilizes the recently developed nuclear-electronic orbital time-dependent configuration interaction (NEO-TDCI) approach, which treats all electrons and specified nuclei quantum mechanically on the same footing.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Institute of Chemistry, Department of Fundamental Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748 - Butantã, São Paulo, 05508-900, Brazil.
The conformational isomerization of nitrous acid (HONO) promoted by excitation of the or stretching normal coordinates is the first observed case of an infrared-induced photochemical reaction. The energy captured by the excited normal modes is redistributed into a highly excited vibrational level of the torsion normal coordinate, which is the isomerization reaction coordinate. Herein, we present simple numerical methods to qualitatively investigate the coupling between the normal coordinates and the possible gateways for vibrational energy redistribution leading to the isomerization process.
View Article and Find Full Text PDFSci Rep
January 2025
Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.
Vanadium dioxide ([Formula: see text]) is a favorable material platform of modern optoelectronics, since it manifests the reversible temperature-induced insulator-metal transition (IMT) with an abrupt and rapid changes in the conductivity and optical properties. It makes possible applications of such a phase-change material in the ultra-fast optoelectronics and terahertz (THz) technology. Despite the considerable interest to this material, data on its broadband electrodynamic response in different states are still missing in the literature.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Institute for Molecules and Materials, FELIX Laboratory, Radboud University, Toernooiveld 7, 6525 ED Nijmegen, The Netherlands.
Symmetry breaking is ubiquitous in chemical transformations and affects various physicochemical properties of materials and molecules; Jahn-Teller (JT) distortion of hexa-coordinated transition-metal-ligand complexes falls within this paradigm. An uneven occupancy of degenerate 3d-orbitals forces the complex to adopt an axially elongated or compressed geometry, lowering the symmetry of the system and lifting the degeneracy. Coordination complexes of Cu are known to exhibit axial elongation, while compression is far less common, although this may be due to the lack of rigorous experimental verification.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Laboratorium für Organische Chemie, Department of Chemistry and Applied Biosciences, ETH Zürich, Zürich 8093, Switzerland.
We report spectroscopic and spectrometric experiments that probe the London dispersion interaction between -butyl substituents in three series of covalently linked, protonated -pyridines in the gas phase. Molecular ions in the three test series, along with several reference molecules for control, were electrosprayed from solution into the gas phase and then probed by infrared multiphoton dissociation spectroscopy and trapped ion mobility spectrometry. The observed N-H stretching frequencies provided an experimental readout diagnostic of the ground-state geometry of each ion, which could be furthermore compared to a second, independent structural readout via the collision cross section.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!