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Stable Carbon-Centered Radicals Based on N-Heterocyclic Carbenes.
- Source :
-
Synlett . 2019, Vol. 30 Issue 15, p1765-1775. 11p. - Publication Year :
- 2019
-
Abstract
- Carbon-centered radicals and diradicaloids based on classical N-heterocyclic carbene (NHC) scaffolds are readily accessible as crystalline solids. The presence of an aryl (Ar) substituent at the C2-position is the key to the remarkable stability of these open-shell species as it provides appropriate room for the spin-density delocalization. Two catalytic as well as high-yielding protocols have been developed to install a suitable aryl group at the C2-position of NHCs. The spin-density in mono-radicals (NHCAr)• is mostly located on the parent carbene carbon (C2) atom. The bridging of two NHCs through a phenylene spacer (C6 H4) n enables the isolation of various p -quinodimethane (p -QDM) derivatives, which may be considered as open-shell Kekulé diradicaloids. The diradical character of these NHC-analogues of Thiele (n = 1), Chichibabin (n = 2), and Müller (n = 3) hydrocarbons [(NHC)(C6 H4) n (NHC)] can be tuned by a rational choice of the size and/or the topology of spacers. In this account, the synthesis, structure, and properties of this new class of radical hydrocarbons is presented. 1 Introduction 2 NHC-Monoradicals 3 NHC-Diradicaloids 4 Conclusion [ABSTRACT FROM AUTHOR]
- Subjects :
- *ARYL group
*CRYSTALS
*RADICALS (Chemistry)
Subjects
Details
- Language :
- English
- ISSN :
- 09365214
- Volume :
- 30
- Issue :
- 15
- Database :
- Academic Search Index
- Journal :
- Synlett
- Publication Type :
- Academic Journal
- Accession number :
- 138346964
- Full Text :
- https://doi.org/10.1055/s-0037-1611887