Nucleophilic Catalysis and Covalent Reaction Intermediates

Опубликована: Янв. 1, 2025

Язык: Английский

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H-Tunneling Rotamerization in Glycine Imine

The Journal of Physical Chemistry Letters, Год журнала: 2025, Номер unknown, С. 2223 - 2230

Опубликована: Фев. 21, 2025

Quantum mechanical tunneling governs the chemical reactivity at cryogenic temperatures. Here we present near-infrared (NIR) light-induced generation of a higher energy conformer glycine imine and its H-tunneling CO bond rotamerization in solid argon (Ar), para-hydrogen (p-H2), dinitrogen (N2) The half-life for highly depends on host matrix is approximately 5 h Ar 18 both p-H2 N2. Surprisingly, experiments revealed much longer than Ar, possibly due to formation complex. Deuteration carboxylic acid group completely inhibits D-tunneling rotamerization. We performed Wentzel – Kramer Brillouin (WKB) canonical variational transition state theory (CVT) calculations, incorporating multidimensional small curvature corrections (SCT), using B3LYP/cc-pVTZ level theory. gas-phase half-lives are 11 according one-dimensional WKB model 1 CVT/SCT model, aligning well with our experimental results.

Язык: Английский

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Generation and UV-photolysis of N-methyleneformamide

Chemical Science, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

N -Methyleneformamide is the simplest acylimine and was characterized under matrix isolation conditions at cryogenic temperatures by infrared UV/Vis spectroscopy. The compound should be considered as a potential interstellar molecule.

Язык: Английский

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UV-photoelectron spectroscopy and MS-CASPT2/CASSCF study of the thermolysis of azidoethyl-methyl sulfide: Characterization and mechanism of the formation of S-methyl-N-sulfenylethanimine

The Journal of Chemical Physics, Год журнала: 2025, Номер 162(19)

Опубликована: Май 16, 2025

The thermal decomposition of azidoethyl methyl sulfide was studied by real-time UV-photoelectron spectroscopy (UV-PES) at temperatures ranging from 773 to 1023 K. Different ionization energies were obtained using density functional theory calculations assign UV-PES spectra. complete active space self-consistent field and multistate second-order perturbation methods used predict the formation different species present in process. N2 S-methyl-N-sulfenylethanimine are generated first step reaction is dissociation molecule into nitrene nitrogen. spin state (singlet or triplet) formed temperature-dependent. At low (T ≤ 650 K), both states with almost same probability; contrast, high ≥ 1000 singlet majority intermediate. From this nitrene, three stable products detected experiments: an imine derivative, a four-member cyclic sulfenyl derivative.

Язык: Английский

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Spectroscopic identification of interstellar relevant 2-iminoacetaldehyde

Chemical Communications, Год журнала: 2023, Номер 59(85), С. 12715 - 12718

Опубликована: Янв. 1, 2023

Imines play a fundamental role in organic synthesis and some of them have been detected space. However, the simplest imines are spectroscopically not well-characterized. Herein we present infrared UV/Vis spectroscopic characterization 2-iminoacetaldehyde using cryogenic matrix isolation techniques. After UV irradiation 2-azidoacetaldehyde solid argon at 3 K identified two conformers 2-iminoacetaldehyde, which can be photochemically interconverted. Deuterium labelling experiments high level ab initio coupled cluster calculations CCSD(T)/CBS theory provide further evidence for formation 2-iminoacetaldehyde.

Язык: Английский

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Mechanism and catalysis of nonenzymatic analogs of amino acid biosynthesis

Advances in physical organic chemistry, Год журнала: 2023, Номер unknown, С. 1 - 39

Опубликована: Янв. 1, 2023

Язык: Английский

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Enantiodetermining processes in the synthesis of alanine, serine, and isovaline

Physical Chemistry Chemical Physics, Год журнала: 2023, Номер 25(42), С. 28829 - 28834

Опубликована: Янв. 1, 2023

Interstellar synthesis of chiral amino acids.

Язык: Английский

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