title: Photochemistry of N-methylformamide: matrix isolation and nonadiabatic dynamics.
abstract: The photochemistry of N-methylformamide (MF) is elucidated by investigating its photodissociation products generated by UV irradiation (248 nm) in an argon matrix (10 K). We find that, starting from trans-MF, prolonged irradiation produces cis-MF, CH3NH2 and CO fragments as major products. Another photoproduct is identified as methylformimidic acid (FIA). Nonadiabatic dynamics simulations starting from both MF conformers revealed that the internal conversion occurs within 1 ps through a C-N dissociation channel. The major product is a weakly bound complex between CH3NH and HCO radicals. This complex owes its existence to the cage effect of the matrix which allows for H-transfer reactions and recombination. By identifying the primary photoisomerization and photodissociation pathways of MF, we gain new insights into the photochemistry of peptide bonds in general, which is a prerequisite for a better understanding of the effect of UV irradiation on living systems.
authors.affiliation: Department of Theory, Max Planck Institute for Coal Research, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.
authors.forename: Rachel
authors.initials: R
authors.lastname: Crespo-Otero
authors.forename: Artur
authors.initials: A
authors.lastname: Mardyukov
authors.forename: Elsa
authors.initials: E
authors.lastname: Sanchez-Garcia
authors.forename: Mario
authors.initials: M
authors.lastname: Barbatti
authors.forename: Wolfram
authors.initials: W
authors.lastname: Sander
mesh_terms: D005559:Formamides / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D055668:Photochemical Processes; D014466:Ultraviolet Rays
chemical_list: D005559:Formamides; C002950:methylformamide