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Updated: May 9, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
A comparison of diamino- and diamidocarbenes toward dimerization
1School of Applied Chemistry and Department of Medical Education, Chung Shan Medical University, 402, Taichung, Taiwan, chlai125@csmu.edu.tw.
Abstract:
In this study, we compare the dimerization of N,N'-diamidocarbene with that of N-heterocyclic carbene (NHC). Less interaction occurred between the filled lone pair of nitrogen and the unfilled lone pair of the carbenic center for a N,N'-diamdiocarbene than did in a saturated NHC because of the resonance between the lone pair of nitrogen and a carbonyl group. Therefore, a N,N'-diamidocarbene exhibits less singlet-triplet splitting. The less singlet-triplet splitting in a heterocyclic carbene containing nitrogen, the more exothermic the dimerization, which is consistent with the conclusion of Thiel et al. (Chem Phys Lett 217:11-16, 1994).
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