One Collision—Two Substituents: Gas‐Phase Preparation of Xylenes under Single‐Collision Conditions DOI Creative Commons
Ya. A. Medvedkov, Anatoliy A. Nikolayev,

Chao He

et al.

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 136(5)

Published: Dec. 11, 2023

Abstract The fundamental reaction pathways to the simplest dialkylsubstituted aromatics—xylenes (C 6 H 4 (CH 3 ) 2 )—in high‐temperature combustion flames and in low‐temperature extraterrestrial environments are still unknown, but critical understand chemistry molecular mass growth processes these extreme environments. Exploiting crossed beam experiments augmented by state‐of‐the‐art electronic structure statistical calculations, this study uncovers a previously elusive, facile gas‐phase synthesis of xylenes through an isomer‐selective 1‐propynyl (methylethynyl, CH CC) with 2‐methyl‐1,3‐butadiene (isoprene, C 5 8 ). dynamics driven barrierless addition radical diene moiety followed extensive isomerization (hydrogen shifts, cyclization) prior unimolecular decomposition accompanied aromatization via atomic hydrogen loss. This overall exoergic affords preparation not only such as around circumstellar envelopes carbon‐rich Asymptotic Giant Branch (AGB) stars, also cold clouds (10 K) hydrocarbon‐rich atmospheres planets their moons Triton Titan. Our established hitherto unknown route potentially more complex, disubstituted benzenes single collision event highlighting significance alkyl‐substituted ethynyl‐mediated aromatic molecules our Universe.

Language: Английский

On the Mechanism and Quantum Tunneling of the CO2 + OH Anion Reaction in Ice: A Computational Study DOI
Avon P. Jayaweera, Bethmini Senevirathne, Samantha Weerasinghe

et al.

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(7), P. 1451 - 1459

Published: June 19, 2024

The mechanism of the reaction between CO2 and OH– (anion) in ice cluster models was determined using density functional theory (DFT), employing ωB97X-D def2-TZVP basis sets for all atoms. A range barriers, 0.08–0.43 eV, were found, lowest energy path has a barrier 0.08 giving rise to bicarbonate ion (HCO3–). Computed rate constants, accounting quantum tunneling by Eckart potential, suggest that + → HCO3– can operate at low temperatures (e.g., 10 K). In contrast, relatively high barriers (0.52–0.74 eV) found OH• (radical) HCO3• reaction, computed constants K) are extremely small. Based on data, we argue react with trapped interstellar K, product HCO3–, is stable ice. On other hand, OH radical does not Therefore, propose anions play role formation precursors complex organic molecules (COMs) medium. present findings will open new dimension explore chemical evolution medium through chemistry ices.

Language: Английский

Citations

0
The Challenge of Characterizing Bimolecular Reactions of Aromatic Compounds via Computational Chemistry. the Case of the $$\text {N(}^2$$D) + Pyridine Reaction and Implications in the Chemistry of the Thermosphere of Titan DOI
Luca Mancini, Marzio Rosi, Nadia Balucani

et al.

Lecture notes in computer science, Journal Year: 2024, Volume and Issue: unknown, P. 84 - 97

Published: Jan. 1, 2024

Language: Английский

Citations

0
Rational ignorance in the search for extra-terrestrial life DOI
Edward D. Zanders

New Astronomy Reviews, Journal Year: 2023, Volume and Issue: 96, P. 101675 - 101675

Published: April 16, 2023

Language: Английский

Citations

0
Neuer Blick auf die Bildung des Sonnensystems DOI Creative Commons
K. Altwegg, M. Rubı́n

Physik in unserer Zeit, Journal Year: 2023, Volume and Issue: 55(2), P. 64 - 71

Published: Nov. 27, 2023

Zusammenfassung Auch wenn sieben Jahre nach Ende der Rosetta‐Mission die Datenanalyse noch nicht beendet ist, haben bisherigen Resultate Vorstellung, dass Kometen primitive Körper sind, hauptsächlich aus Wasser, CO und 2 bestehen, klar widerlegt. Die chemischen physikalischen Eigenschaften des lassen auf eine sanfte Agglomeration in einer kalten Umgebung schließen, wobei viele Moleküle einen präsolaren Ursprung haben, insbesondere auch Wasser. chemische Zusammensetzung eines ist höchst komplex. Darunter sind etliche präbiotische Moleküle, These stützen, Kometeneinschläge möglicherweise Entstehung Lebens Erde befördert haben.

Citations

0
One Collision—Two Substituents: Gas‐Phase Preparation of Xylenes under Single‐Collision Conditions DOI Creative Commons
Ya. A. Medvedkov, Anatoliy A. Nikolayev,

Chao He

et al.

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 136(5)

Published: Dec. 11, 2023

Abstract The fundamental reaction pathways to the simplest dialkylsubstituted aromatics—xylenes (C 6 H 4 (CH 3 ) 2 )—in high‐temperature combustion flames and in low‐temperature extraterrestrial environments are still unknown, but critical understand chemistry molecular mass growth processes these extreme environments. Exploiting crossed beam experiments augmented by state‐of‐the‐art electronic structure statistical calculations, this study uncovers a previously elusive, facile gas‐phase synthesis of xylenes through an isomer‐selective 1‐propynyl (methylethynyl, CH CC) with 2‐methyl‐1,3‐butadiene (isoprene, C 5 8 ). dynamics driven barrierless addition radical diene moiety followed extensive isomerization (hydrogen shifts, cyclization) prior unimolecular decomposition accompanied aromatization via atomic hydrogen loss. This overall exoergic affords preparation not only such as around circumstellar envelopes carbon‐rich Asymptotic Giant Branch (AGB) stars, also cold clouds (10 K) hydrocarbon‐rich atmospheres planets their moons Triton Titan. Our established hitherto unknown route potentially more complex, disubstituted benzenes single collision event highlighting significance alkyl‐substituted ethynyl‐mediated aromatic molecules our Universe.

Language: Английский

Citations

0