Weakly Bound Complex Formation between HCN and CH₃Cl: A Matrix-Isolation and Computational Study

Abstract

The matrix-isolated infrared spectrum of a hydrogen cyanide–methyl chloride complex was investigated in a solid argon matrix. HCN and CH3Cl were co-condensed onto a substrate held at 10 K with an excess of argon gas, and the infrared spectrum was measured using Fourier-transform infrared spectroscopy. Quantum chemical geometry optimization, harmonic frequency, and natural bonding orbital calculations indicate stabilized hydrogen- and halogen-bonded structures. The two resulting weakly bound complexes are both composed of one CH3Cl molecule bound to a (HCN)3 subunit, where the three HCN molecules are bound head-to-tail in a ring formation. Our study suggests thatin the presence of CH3Clthe formation of (HCN)3 is promoted through complexation. Since HCN aggregates are an important precursor to prebiotic monomers (amino acids and nucleobases) and other life-bearing polymers, this study has astrophysical implications toward the search for life in space.

Interpretable Machine Learning Model for Predicting Interaction Energies between Dimethyl Sulfide and Potential Absorbing Solvents

“…The diagrams of the RDG-ρ­( r ) scatter, RDG-sign­(λ 2 )­ρ scatter, and RDG equipotential surface are presented to illustrate the possible types, strengths, and locations of weak interactions in different binary molecular systems. The judgment criteria for the RDG theory have been discussed in previous publications. − The spikes appearing in the RDG-ρ­( r ) and RDG-sign­(λ 2 )­ρ scatter diagrams are displayed in Figure a,b, respectively. The scatter diagrams can be divided into three regions: the first region with sign­(λ 2 )­ρ ranging from −0.05 to −0.01, representing the hydrogen-bond interaction, the second region having sign­(λ 2 )­ρ ranging from −0.01 to 0.01 indicating the van der Waals interaction, and the third region of sign­(λ 2 )­ρ ranging from 0.01 to 0.05 denoting the steric hindrance interaction.…”

3-Fluoro-2H-azirine: Generation, Characterization, and Photochemistry

“…This intramolecular isomerization has been previously observed for matrix-isolated HCCNCO under irradiation at 266 nm. 59 The absence of intermediate HCCNCO among the pyrolysis In the IR spectrum of the pyrolysis products (Figure 1B), the IR bands for fragmentation species FCO (e, 1856 and 1023 cm −1 ), 60 CH 2 CN (f, 1432.3, 1026.0, and 664.6 cm −1 ), 61 CO (h, 2144.1 cm −1 ), 62 H 2 O (k, 3727.3, 3634.7, and 1597.0 cm −1 ), 63 F 2 CO (l, 1941CO (l, .1, 1909CO (l, .7, 1237, and 767.9 cm −1 ), 64 CO 2 (m, 2347.6 cm −1 ), 62 and HCN (n, 3306, 2093, and 720 cm −1 ) 65 were also observed. The presence of CH 2 CN and FCO implies a competing decomposition pathway for CH 2 CFNCO via 1,3-F migration with concurrent C−N bond cleavage.…”

“…In the IR spectrum of the pyrolysis products (Figure B), the IR bands for fragmentation species FCO ( e , 1856 and 1023 cm –1 ), CH 2 CN ( f , 1432.3, 1026.0, and 664.6 cm –1 ), CO ( h , 2144.1 cm –1 ), H 2 O ( k , 3727.3, 3634.7, and 1597.0 cm –1 ), F 2 CO ( l , 1941.1, 1909.7, 1237.4, 960.4, and 767.9 cm –1 ), CO 2 ( m , 2347.6 cm –1 ), and HCN ( n , 3306, 2093, and 720 cm –1 ) were also observed. The presence of CH 2 CN and FCO implies a competing decomposition pathway for CH 2 CFNCO via 1,3-F migration with concurrent C–N bond cleavage.…”

Matrix-formation dynamics dictate methyl nitrite conformer abundance

“…The matrix-isolation spectrometer has been described in detail previously. 76 Briefly, the matrix-isolated sample is prepared in the center of the chamber on a 1-inch KBr salt-glass substrate that is cooled by a CTI Model 22 cryocooler. The temperature of the sample holder is monitored and controlled through both a silicon diode and resistive heaters connected to a Lakeshore Model 331 temperature controller.…”