Joshi Prasad Ramesh, Lee Yuan-Pern
Department of Applied Chemistry and Institute of Molecular Science, National Yang Ming Chiao Tung University, Hsinchu, Taiwan.
Center for Emergent Functional Matter Science, National Yang Ming Chiao Tung University, Hsinchu, Taiwan.
Commun Chem. 2022 May 12;5(1):62. doi: 10.1038/s42004-022-00677-5.
Methylamine CHNH is considered to be an important precursor of interstellar amino acid because hydrogen abstraction might lead to the aminomethyl radical •CHNH that can react with •HOCO to form glycine, but direct evidence of the formation and spectral identification of •CHNH remains unreported. We performed the reaction H + CHNH in solid p-H at 3.2 K and observed IR spectra of •CHNH and CHNH upon irradiation and when the matrix was maintained in darkness. Previously unidentified IR spectrum of •CHNH clearly indicates that •CHNH can be formed from the reaction H + CHNH in dark interstellar clouds. The observed dual-cycle mechanism containing two consecutive H-abstraction and two H-addition steps chemically connects CHNH and CHNH in interstellar media and explains their quasi-equilibrium. Experiments on CDNH produced CDHNH, in addition to •CDNH and CDNH, confirming the occurrence of H addition to •CDNH.
甲胺CH₃NH₂被认为是星际氨基酸的重要前体，因为氢提取可能导致氨基甲基自由基•CH₂NH，它可以与•HOCO反应形成甘氨酸，但•CH₂NH形成和光谱鉴定的直接证据仍未报道。我们在3.2 K的固态对-氢中进行了H + CH₃NH₂反应，并在辐照时以及基质保持黑暗时观察了•CH₂NH和CH₃NH₂的红外光谱。先前未鉴定的•CH₂NH红外光谱清楚地表明，•CH₂NH可以在黑暗的星际云中通过H + CH₃NH₂反应形成。观察到的包含两个连续氢提取和两个氢加成步骤的双循环机制在化学上连接了星际介质中的CH₃NH₂和•CH₂NH，并解释了它们的准平衡。对CD₃NH的实验除了产生•CD₂NH和CD₃NH外，还产生了CD₂HNH，证实了氢加成到•CD₂NH上的发生。
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