Low-temperature indene synthesis could form a molecular building block for non-planar polycyclic aromatics and fullerenes.

The azulene (C10H8) molecule, the simplest polycyclic aromatic hydrocarbon (PAH) carrying a fused seven- and five-membered ring, is regarded as fundamental molecular building block of saddle-shaped carbonaceous nanostructures such curved nanographenes in interstellar medium. However, an understanding underlying gas-phase formation mechanisms this nonbenzenoid 10π-Hückel molecule under low-temperature conditions its infancy. Here, by merging crossed beam experiments with electronic structure...

Significance Carbenes represent key reactive intermediates in molecular mass growth processes leading to carbonaceous nanostructures the interstellar medium and combustion systems. However, due their short lifetimes tendency for dimerization, carbenes one of foremost obscured classes intermediates, with preparation gas phase remaining largely elusive. By merging beams electronic structure quasi-classical trajectory calculations exploiting triplet pentadiynylidene (HCCCCCH) singlet...

The regions of the C13H11 potential energy surface (PES) related to unimolecular isomerization and decomposition 1-methylbiphenylyl radical accessed by 1-/2-methylnaphthyl + C2H2 reactions have been explored ab initio G3(MP2,CC)//B3LYP/6-311G(d,p) calculations. kinetics these relevant growth polycyclic aromatic hydrocarbons (PAH) under high-temperature conditions in circumstellar envelopes combustion flames has studied employing RRKM-Master Equation approach. reaction proceeding via a...

Significance Since the detection of carbonyl monosulfide (CS) in star-forming regions, about 200 molecules as complex fullerenes have been detected interstellar and circumstellar environments, but formation routes to organosulfur remained essentially elusive. Exploiting thioformaldehyde (H 2 CS) its thiohydroxycarbene isomer (HCSH), we deliver compelling testimony via laboratory experiments, electronic-structure theory, astrochemical modeling, quasi-classical trajectory studies that these...

The 1-indenyl (C 9 H 7 • ) radical, a prototype aromatic and resonantly stabilized free radical carrying six- five-membered ring, has emerged as fundamental molecular building block of nonplanar polycyclic hydrocarbons (PAHs) carbonaceous nanostructures in deep space combustion systems. However, the underlying formation mechanisms have remained elusive. Here, we reveal an unconventional low-temperature gas-phase via barrierless ring annulation involving reactions atomic carbon [C( 3 P)] with...

The fulvenallene molecule (C7H6) has been synthesized via the elementary gas-phase reaction of methylidyne radical (CH) with benzene (C6H6) on doublet C7H7 surface under single collision conditions. barrier-less route to cyclic involves addition π-electron density leading eventually a Jahn-Teller distorted tropyl (C7H7) intermediate and exotic ring opening-ring contraction sequences terminated by atomic hydrogen elimination. methylidyne-benzene system represents benchmark probe outcome...

The crossed beams reactions of the 1-propynyl radical (CH3CC; X2A1) with 1,3-butadiene (CH2CHCHCH2; X1Ag), 1,3-butadiene-d6 (CD2CDCDCD2; 1,3-butadiene-d4 (CD2CHCHCD2; and 1,3-butadiene-d2 (CH2CDCDCH2; X1Ag) were performed under single collision conditions at energies about 40 kJ mol–1. underlying reaction mechanisms unraveled through combination experimental data electronic structure calculations CCSD(T)-F12/cc-pVTZ-f12//B3LYP/6-311G(d,p) + ZPE(B3LYP/6-311G(d,p) level theory along...

Center-of-mass velocity flux contour maps for the reactions of 1-propynyl with ethylene atomic hydrogen loss leading to 1-penten-3-yne.

The gas-phase bimolecular reaction of the methylidyne (CH; X2Π) radical with vinylacetylene (H2CCHCCH; X1A') was conducted at a collision energy 20.3 kJ mol-1 under single conditions exploiting crossed molecular beam experimental results merged ab initio electronic structure calculations and dynamics (AIMD) simulations. laboratory data reveal that proceeds barrierlessly via indirect scattering through long-lived C5H5 intermediate(s) ultimately dissociating to C5H4 isomers along atomic...

Abstract The crossed molecular beams reactions of the 1-propynyl radical (CH 3 CC; X 2 A 1 ) with benzene (C 6 H ; 1g and D6-benzene D were conducted to explore formation C 9 8 isomers under single-collision conditions. underlying reaction mechanisms unravelled through combination experimental data electronic structure statistical RRKM calculations. These suggest 1-phenyl-1-propyne 5 CCCH via barrierless addition forming a low-lying doublet intermediate that dissociates by hydrogen atom...

Gas-phase 1,3,5,7-cyclooctatetraene (C8H8) and triplet aromatic were formed for the first time through bimolecular methylidyne radical (CH)-1,3,5-cycloheptatriene (C7H8) reactions under single-collision conditions on a doublet surface. The reaction involves addition to olefinic π electron system of 1,3,5-cycloheptatriene followed by isomerization ring expansion an 1,3,5-cyclooctatrien-7-yl (C8H9•). chemically activated intermediate undergoes unimolecular decomposition...

The crossed molecular beam reactions of the methylidyne radical (CH; X2 Π) with 1,3-butadiene (CH2 CHCHCH2 ; X1 Ag ) along their (partially) deuterated counterparts were performed at collision energies 20.8 kJ mol-1 under single conditions. Combining our laboratory data ab initio calculations, we reveal that may add barrierlessly to terminal carbon atom and/or carbon-carbon double bond 1,3-butadiene, leading doublet C5 H7 intermediates life times longer than rotation periods. These complexes...

The crossed molecular beam reactions of the methylidyne radical (CH; X2Π) with propylene (CH3CHCH2; X1A′) along (partially) substituted reactants were conducted at collision energies 19.3 kJ mol–1. Combining our experimental data ab initio electronic structure and statistical calculations, is revealed to add barrierlessly carbon–carbon double bond reactant resulting in a cyclic doublet C4H7 intermediate lifetime longer than its rotation period. These adducts undergo nonstatistical...

The bimolecular gas-phase reaction of the methylidyne radical (CH; X2Π) with 1,2-butadiene (CH2CCHCH3; X1A′) was investigated at a collision energy 20.6 kJ mol–1 under single conditions. Combining our laboratory data high-level electronic structure calculations, we reveal that this proceeds through barrierless addition to carbon–carbon double bonds leading doublet C5H7 intermediates. These adducts undergo nonstatistical unimolecular decomposition atomic hydrogen elimination least cyclic...

Methyltriacetylene - the largest methylated polyacetylene detected in deep space has been synthesized gas phase via bimolecular reaction of 1-propynyl radical with diacetylene under single-collision conditions. The barrier-less route to methyltriacetylene represents a prototype polyyne chain extension through substitution mechanism and provides novel low temperature route, which propynyl piggybacks methyl group be incorporated into polyynes. This overcomes key obstacle previously postulated...

Abstract The triafulvene molecule (c‐C 4 H )—the simplest representative of the fulvene family—has been synthesized for first time in gas phase through reaction methylidyne radical (CH) with methylacetylene (CH 3 CCH) and allene (H 2 CCCH ) under single‐collision conditions. experimental computational data suggest is formed by barrierless cycloaddition to π‐electron density either C isomer followed unimolecular decomposition elimination atomic hydrogen from CH or groups reactants. dipole...

An important environmental problem related to the use of fossil fuels is formation soot during combustion. Mechanisms oxidation, which alleviates its emission into environment, are not fully understood. The reaction O with a radical C 15 H 9 may play an role in In this article, molecule was chosen as model surface. paper discusses various pathways resulting from + reaction. Relative energies, frequencies and optimal geometries reactants, products, intermediates transition states have been...

The mechanism and chemical dynamics of the reaction ground electronic state atomic carbon C(3Pj) with cyclopropane c-C3H6 have been explored by combining crossed molecular beams experiments structure calculations pertinent triplet C4H6 potential energy surface statistical computations product branching ratios under single-collision conditions. experimental findings suggest that proceeds via indirect scattering through intermediate(s) leading to C4H5 product(s) plus hydrogen a tight exit...

Triafulven (C4H4), das einfachste Mitglied der Fulvenfamilie, wird als naszierendes Produkt bei Reaktion von Methylidin-Radikalen (CH) mit Allen (CH2CCH2) und Methylacetylen (CH3CCH) gebildet. Wie A. M. Mebel, R. I. Kaiser Mitarbeiter in ihrem Forschungsartikel auf S. 15634 zeigen, die Bildung durch Cycloaddition des CH-Radikals an ungesättigte C3H4-Bindungen unmittelbar nachfolgende Abspaltung eines Wasserstoffatoms begünstigt.