Spectroscopic and computational characterization of lanthanide-mediated N-H and C-H bond activation of methylamine
Silver Nyambo1, Yuchen Zhang1, Dong-Sheng Yang1
1Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, USA.
Abstract:
Ln (Ln = La and Ce) atom reactions with methylamine are carried out in a pulsed-laser vaporization supersonic molecular beam source. A series of dehydrogenation species are observed with time-of-flight mass spectrometry, and the dehydrogenated Ln-containing species in the formula Ln(NCH3) are characterized by mass-analyzed threshold ionization (MATI) spectroscopy and density functional theory and multiconfiguration spin-orbit coupling computations. The MATI spectrum of La(NCH3) consists of two vibronic band systems that are assigned to the ionization of the 2A1 ground state of the C3v isomer La(N-CH3) and the 2A' ground state of the Cs isomer La(NH-CH2). The MATI spectrum of Ce(NCH3) also displays two band systems, which are attributed to the ionization of the low-energy spin-orbit coupling states of the C3v isomer Ce(N-CH3). Ln(N-CH3) is formed by the concerted dehydrogenation of the amino group, while La(NH-CH2) is formed by the dehydrogenation of both amino and methyl groups. Ce(NH-CH2) is presumably formed in the reaction based on the computational predictions but not observed by the spectroscopic measurements.
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