Dihydroimidazol-2-ylidene

Dihydroimidazol-2-ylidene

Names
IUPAC name Dihydroimidazol-2-ylidene
Systematic IUPAC name Imidazolidin-2-ylidene
Identifiers
3D model (Jmol)	Interactive image
ChemSpider	11350507
InChI InChI=1S/C3H6N2/c1-2-5-3-4-1/h4-5H,1-2H2 Key: JKQUEGZDRZXJNY-UHFFFAOYSA-N InChI=1/C3H6N2/c1-2-5-3-4-1/h4-5H,1-2H2 Key: JKQUEGZDRZXJNY-UHFFFAOYAT
SMILES [C]1NCCN1
Properties
Chemical formula	C3H6N2
Molar mass	70.10 g·mol^−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Dihydroimidazol-2-ylidene is a hypothetical organic compound with formula C₃H₆N₂. It would be a heterocyclic compound, formally derived from imidazolidine with two hydrogen atoms removed from carbon number 2, leaving two vacant chemical bonds — which makes it a carbene.

Although carbenes in general are extremely short-lived, some derivatives of this compound are surprisingly stable, and form an important class of the persistent carbenes. They include the first stable carbenes postulated (but not isolated) by Hans-Werner Wanzlick around 1960.^[1][2][3]

Wanzlick's mechanism for the reaction of dihydroimidazol-2-ylidene with electrophiles

1,3-Dimesityl-imidazol-4,5-dihydro-2-ylidene, a stable carbene without delocalization around the ring containing the carbenic carbon.
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They also include an example of the (saturated) imidazolin-2-ylidene (carbene) reported by A.J. Arduengo in 1995.^[4]

References

1. H.-W. Wanzlick and E. Schikora (1960). "Ein neuer Zugang zur Carben-Chemie". Angewandte Chemie. 72 (14): 494. doi:10.1002/ange.19600721409.
2. H.-W. Wanzlick and E. Schikora (1960). "Ein nucleophiles Carben". Chemische Berichte. 94 (9): 2389–2393. doi:10.1002/cber.19610940905.
3. H.-W. Wanzlick (1962). "Aspects of Nucleophilic Carbene Chemistry". Angew. Chem. Int. Ed. Engl. 1 (2): 75. doi:10.1002/anie.196200751.
4. A. J. Arduengo, III, H. V. R. Dias, R. L. Harlow, and M. Kline (1992). "Electronic stabilization of nucleophilic carbenes". J. Am. Chem. Soc. 114 (14): 5530. doi:10.1021/ja00040a007.