Electronic structure analysis of riboflavin: OVGF and EOM-CCSD study.

Fatemeh Abyar, Igor Novak

Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy 2022 Jan 05

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The computational simulation of the photoelectron spectrum of active form of vitamin B2 is reported in the gas phase. In this work, we determine relative stability of eight riboflavin conformers by conformational search first with molecular mechanics AMMP potential in VEGA software at 553 K. Relative abundance of conformers was deduced from Boltzmann population weighting method (BPW). The three most stable conformers were then selected for computing valence, vertical ionization energies. We used high-level Equation-of-Motion Coupled-Cluster (EOM-IP-CCSD) method to obtain valence ionization energies (IP). In order to characterize the nature of ionization processes pertaining to different spectral bands, natural bonding orbital (NBO) method and molecular electrostatic potentials (MEP) were used to obtain orbital electron densities. The influence of the electronic structure of riboflavin on its biological activity is manifested via reduction of ionization energies of outermost orbitals which makes electron densities of these orbitals more readily available to participate in ligand-receptor bonding. Copyright © 2021 Elsevier B.V. All rights reserved.

Citation

Fatemeh Abyar, Igor Novak. Electronic structure analysis of riboflavin: OVGF and EOM-CCSD study. Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy. 2022 Jan 05;264:120268