Anharmonic Vibrational Frequencies and Spectroscopic Constants for the Six Conformers of 1,2-Diiminoethane: A Promising Prebiotic Molecule for Astronomical Detection

ACS Earth and Space Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 11, 2025

Language: Английский

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H-Tunneling Rotamerization in Glycine Imine

The Journal of Physical Chemistry Letters, Journal Year: 2025, Volume and Issue: unknown, P. 2223 - 2230

Published: Feb. 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.

Language: Английский

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Primary Pyrrolimines and Pyridinimines

Molecules, Journal Year: 2025, Volume and Issue: 30(6), P. 1239 - 1239

Published: March 10, 2025

The association of an aromatic ring with N-H-unsubstituted imine generates families compounds that have been little studied until now except when the is a phenyl group. Recently, such imines substituted by furan or thiophene group synthesized. This work reports similar study where pyrrole pyridine directly linked to N-unsubstituted aldimine ketimine in order isolate and open way knowledge their physicochemical properties. lower volatility derivatives compared aryl, furan, greatly increases difficulty synthesis isolation these kinetically unstable compounds.

Language: Английский

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Generation and UV-photolysis of N-methyleneformamide

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 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.

Language: 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, Journal Year: 2025, Volume and Issue: 162(19)

Published: May 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.

Language: Английский

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Glycine Imine—The Elusive α‐Imino Acid Intermediate in the Reductive Amination of Glyoxylic Acid

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(11)

Published: Jan. 19, 2023

Simple unhindered aldimines tend to hydrolyze or oligomerize and are therefore spectroscopically not well characterized. Herein we report the formation spectroscopic characterization of simplest imino acid, namely glycine imine, by cryogenic matrix isolation IR UV/Vis spectroscopy. Glycine imine forms after UV irradiation 2-azidoacetic acid N2 extrusion in anti-(E,E)- anti-(Z,Z)-conformation that can be photochemically interconverted. In pyrolysis experiments with cannot trapped as it further decarboxylates aminomethylene. aqueous solution is hydrolyzed hydroxy hydrated glyoxylic acid. At higher concentrations presence FeII SO4 a reducing agent undergoes self-reduction oxidative decarboxylation chemistry. may seen one key reaction intermediates connecting prebiotic amino sugar

Language: Английский

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Spectroscopic identification of interstellar relevant 2-iminoacetaldehyde

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(85), P. 12715 - 12718

Published: Jan. 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.

Language: Английский

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Synthesis and Characterization of N-Unsubstituted 2- and 3-Furanimines

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(15), P. 11026 - 11030

Published: July 11, 2024

N-unsubstituted 2-furanmethanimine and 3-furanmethanimine are the simplest derivatives of an imine family containing numerous drugs. They have been prepared in gas phase by dehydrocyanation corresponding α-aminonitriles, characterized IR NMR spectroscopy at low temperature used transimination reactions. The kinetic stability furanaldimines lies between that alkylated arylated derivatives, demonstrating role played substituent. triethylborane complexes aldimines were synthesized reacting nitriles with superhydride.

Language: Английский

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High-temperature water unlocks urea as nitrogen-source towards imidazoles

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(20), P. 10411 - 10421

Published: Jan. 1, 2024

The synergy between high-temperature water and urea propels the synthesis of imidazoles via Debus-Radziszewski multicomponent reaction in a catalys-free fashion.

Language: Английский

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Glycinimin – Das schwer fassbare α‐Iminosäure‐Intermediat bei der Reduktiven Aminierung der Glyoxylsäure

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 135(11)

Published: Jan. 19, 2023

Abstract Einfache ungehinderte Aldimine neigen dazu, zu hydrolysieren oder oligomerisieren und sind daher spektroskopisch nicht gut charakterisiert. Wir berichten hier über die Bildung spektroskopische Charakterisierung der einfachsten Iminosäure, nämlich Glycinimin, mittels kryogener Matrixisolation, IR‐ UV/Vis‐Spektroskopie. Glycinimin bildet sich nach UV‐Bestrahlung von 2‐Azidoessigsäure durch N 2 ‐Freisetzung in anti ‐( E , )‐ Z )‐Konformationen, photochemisch ineinander umgewandelt werden können. In Pyrolyseversuchen gekoppelt mit Matrixisolation kann isoliert werden, da es weiter Aminomethylen decarboxyliert. wässriger Lösung wird Hydroxyglycin hydratisierter Glyoxylsäure hydrolysiert. Bei höheren Konzentrationen Gegenwart Fe II SO 4 als Reduktionsmittel reduziert oxidative Decarboxylierung selbst. ein Schlüsselintermediat zwischen präbiotischer Aminosäure‐ Zuckerbildung angesehen werden.

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