Carbenes

thumb|60px|Methylene (compound)|Methylene is the simplest carbene. In organic chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The general formula is or where the R represents substituents or hydrogen atoms.

chemical compound

Dichlorocarbene is the reactive intermediate with chemical formula CCl2. Although this chemical species has not been isolated, it is a common intermediate in organic chemistry, being generated from chloroform. This bent diamagnetic molecule rapidly inserts into other bonds.

chemical compound CH₂(2•), the simplest carbene

Cyclopropenylidene, or '''c-C3H2''', is a partially aromatic molecule belonging to a highly reactive class of organic molecules known as carbenes. On Earth, cyclopropenylidene is only seen in the laboratory due to its reactivity. However, cyclopropenylidene is found in significant concentrations in the interstellar medium (ISM) and on Saturn's moon Titan. Its C2v symmetric isomer, propadienylidene (CCCH2) is also found in the ISM, but with abundances about an order of magnitude lower. A third C2 symmetric isomer, propargylene (HCCCH), has not yet been detected in the ISM, most likely due to it

Dihydroxymethylidene or carbonous acid is a chemical compound with formula . It is an unstable tautomer of formic acid. There is no evidence that this compound exists in solution, but the molecule has been detected in the gas phase. Many related carbenes are known, although they are often transient.

class of organometalic compounds

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.

Difluorocarbene is the chemical compound with formula CF2. It has a short half-life, 0.5 and 20 ms, in solution and in the gas phase, respectively. Although highly reactive, difluorocarbene is an intermediate in the production of tetrafluoroethylene, which is produced on an industrial scale as the precursor to Teflon (PTFE).

In chemistry a carbenoid is a reactive intermediate that shares reaction characteristics with a carbene. In the Simmons–Smith reaction the carbenoid intermediate is a zinc / iodine complex that takes the form of

a type of carbene demonstrating particular stability

SIMes (or H2Imes) is an N-heterocyclic carbene. It is a white solid that dissolves in organic solvents. The compound is used as a ligand in organometallic chemistry. It is structurally related to the more common ligand IMes but with a saturated backbone (the S of SIMes indicates a saturated backbone). It is slightly more flexible and is a component in Grubbs II. It is prepared by alkylation of trimethylaniline by dibromoethane followed by ring closure and dehydrohalogenation.