Dinitrites are effective nitrosating reagents in preparative chemistry and their decomposition products are involved in the atmospheric reaction of volatile organic compounds with nitrogen oxides (NO). In this work, photodissociation dynamics of five alkyl dinitrites were investigated by detecting the LIF spectra of the dissociation products and theoretical calculations. The results showed that the C-C bond connecting the two nitrosooxy (-ONO) functional groups was the weakest bond in vicinal dinitrites and aldehydes were the dissociation products. For dinitrites with two ONO groups separated by a CH group, vinoxy and 1-methylvinoxy radicals were detected as the fragments via photodissociation, indicating a different mechanism compared to thermal decomposition. This observation demonstrated that a new reactive pathway could be initiated by photolysis of dinitrites.
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http://dx.doi.org/10.1039/c6cp03049a | DOI Listing |
J Comput Chem
January 2025
Nantes Université, CNRS, CEISAM UMR 6230, Nantes, France.
Carbonyl complexes of metals with an α-diimine ligand exhibit both emission and ligand-selective photodissociation from MLCT states. Studying this photodissociative mechanism is challenging for experimental approaches due to an ultrafast femtosecond timescale and spectral overlap of multiple photoproducts. The photochemistry of a prototypical system is investigated with non-adiabatic dynamic simulations.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Institute of Modern Physics, Shaanxi Key Laboratory for Theoretical Physics Frontiers, Northwest University, Xi'an, Shaanxi 710127, China.
The full-dimensional potential energy surface (PES) for the photodissociation of HNCS in the S(″) electronic state has been built up by the neural network method based on more than 48,000 points, which were calculated at the multireference configuration interaction level with Davidson correction using the augmented correlation consistent polarized valence triple-ζ basis set. It was found that two minima, namely, and isomers of HNCS, and seven stationary points exist on the S PES for the three dissociation pathways: HNCS(S) → H + NCS/HNC + S(D)/HN(Δ) + CS(Σ). The dissociation energies of two lowest product channels H + NCS and HNC + S(D) calculated on the PES are in good agreement with experimental results, validating the high accuracy of the PES.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 123, 28006 Madrid, Spain.
Photodissociation of the CH2Cl radical is investigated by using high-level multireference configuration interaction ab initio methods, including the spin-orbit coupling. All possible fragmentation pathways, namely, CH2Cl + hν → CH2 + Cl, HCCl + H, and CCl + H2, have been analyzed. The potential-energy curves of the ground and several excited electronic states along the corresponding dissociating bond distance of each pathway have been calculated.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Department of Chemistry, Bagley Hall, Box 351700, University of Washington, Seattle, Washington 98195-1700, United States.
We report a study of internal covalent cross-linking with photolytically generated diarylnitrile imines of N-terminal arginine, lysine, and histidine residues in peptide conjugates. Conjugates in which a 4-(2-phenyltetrazol-5-yl)benzoyl group was attached to C-terminal lysine, that we call RAAA--K, KAAA--K, and HAAA--K, were ionized by electrospray and subjected to UV photodissociation (UVPD) at 213 nm. UVPD triggered loss of N and proceeded by covalent cross-linking to nitrile imine intermediates that involved the side chains of N-terminal arginine, lysine, and histidine, as well as the peptide amide groups.
View Article and Find Full Text PDFPhys Chem Chem Phys
December 2024
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Collaborative Innovation Centre of Chemistry for Energy Materials (iChEM), Fudan University, Shanghai, 200438, China.
SiO is a widespread molecule found in interstellar space, and its dissociation requires a substantial input of energy due to its high bond energy of 8.34 eV. The present study initially demonstrated across a broad range of ultraviolet (UV) wavelengths (243-288 nm) the one-photon and two-photon dissociation of SiO molecules, which were generated from the laser ablation of a Si rod colliding with an oxygen molecular beam.
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