Benzvalene

Benzvalene is an organic compound and one of several isomers of benzene.^[1] It was first synthesized in 1967 by K. E. Wilzbach et al. ^[2] via photolysis of benzene and the synthesis was later improved by Thomas J. Katz et al.^[3][4]

Benzvalene

Names
Preferred IUPAC name Tricyclo[3.1.0.02,6]hex-3-ene
Identifiers
CAS Number	659-85-8 N
3D model (JSmol)	Interactive image
ChemSpider	120239 N
PubChem CID	136470
CompTox Dashboard (EPA)	DTXSID00216109
InChI InChI=1S/C6H6/c1-2-4-5-3(1)6(4)5/h1-6H N Key: VMQPMGHYRISRHO-UHFFFAOYSA-N N InChI=1/C6H6/c1-2-4-5-3(1)6(4)5/h1-6H Key: VMQPMGHYRISRHO-UHFFFAOYAJ
SMILES C1=CC2C3C1C23
Properties
Chemical formula	C6H6
Molar mass	78.114 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

The 1971 synthesis consisted of treating cyclopentadiene with methyllithium in dimethyl ether and then with dichloromethane and methyllithium in dimethyl ether at −45 °C. It can also be formed in low yield (along with fulvene and Dewar benzene) by irradiation of benzene at 237 to 254 nm.^[5] The hydrocarbon in solution was described as having an extremely foul odor. Due to the high steric strain present in benzvalene, the pure compound (~71 kcal/mol higher in energy than benzene) easily detonates, for example by scratching.

The compound converts to benzene with a chemical half-life of approximately 10 days. This symmetry-forbidden transition is believed to take place through a diradical intermediate.^[6]

Polybenzvalene

Benzvalene can be polymerized in a ring opening metathesis polymerisation to polybenzvalene.^[7] This polymer contains highly strained bicyclobutane rings which again makes it a sensitive material. The rings can be isomerized to 1,3-dienes and for this reason polybenzvalene has been investigated as a precursor to polyacetylene.