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Updated: Feb 14, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Spectroscopic Evidence for Aminomethylene (H-C̈-NH2 )-The Simplest Amino Carbene
André K Eckhardt1, Peter R Schreiner1
1Institute of Organic Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 17, 35392, Giessen, Germany.
Abstract:
Although N-heterocyclic carbenes have been well-studied, the simplest aminocarbene, aminomethylene H-C̈-NH2 , has not been spectroscopically identified to date. Herein we report the gas-phase preparation of aminomethylene by high-vacuum flash pyrolysis of cyclopropylamine and subsequent trapping of the pyrolysate in an inert argon matrix at 12 K. Aminomethylene was characterized by matching matrix IR and UV/Vis spectroscopic data with ab initio coupled cluster computations. After UV irradiation of the matrix aminomethylene rearranges to its isomer methanimine (formaldimine) H2 C=NH. Based on our experimental results and computations aminomethylene has a singlet ground state with a reaction barrier of almost 46 kcal mol-1 to methanimine so that H-tunneling is excluded.
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