248-58-8

Basic information

• Product Name: Indeno[2,1-a]indene(6CI,7CI,8CI,9CI)
• Synonyms: 1.2,4.5-Dibenzpentalene;Dibenzo[b,f]pentalene; Diphensuccinda-9,11-diene
• CAS NO: 248-58-8
• Molecular Formula: C16H10
• Molecular Weight: 202.255
• Mol File: 248-58-8.mol

Chemical Properties

• CAS DataBase Reference: Indeno[2,1-a]indene(6CI,7CI,8CI,9CI)(CAS DataBase Reference)
• NIST Chemistry Reference: Indeno[2,1-a]indene(6CI,7CI,8CI,9CI)(248-58-8)
• EPA Substance Registry System: Indeno[2,1-a]indene(6CI,7CI,8CI,9CI)(248-58-8)

Safety Data

• Hazardous Substances Data: 248-58-8(Hazardous Substances Data)

Upstream product

• 886-66-8 1,4-diphenyl-1,3-butadiyne 
• 1090-13-7 5,12-naphthacenequinone 
• 259-56-3 benzo[b]biphenylene 
• 3074-03-1 11H-Benzo[b]fluoren-11-one 
• 374621-33-7 9,10-bis[methoxy(trimethylsilyl)methyl]anthracene 

Downstream Products

• 6543-29-9 indenoindene 

Relevant articles and documents

Intramolecular behaviors of anthryldicarbenic systems: Dibenzo[b,f]pentalene and, 1H,5H-dicyclobuta[de,kl]anthracene

9,10-Bis[methoxy(trimethylsilyl)methyl]anthracenes (24), synthesized from 9,10-dilithioanthracene (26) and bromomethoxytrimethylsilylmethane (27, 2 equiv), decompose (550-650 °C/10-3 mmHg) carbenically to dibenzo[b,f]pentalene (28, >48%). 9,10-Anthryldicarbenes 39 or their equivalents convert to pentalene 28 rather than di-peri-cyclobutanthracenes 30 and 31, benzobiphenylene 32, or extended rearrangement products 33-38. Formation of 28 from 24 raises questions with respect to the behavior of 1,3,4,6-cycloheptatetraenyl-1-carbenes 49, 2,4,5,7-cyclooctatetraenylidene 51, 2,5,7-cyclooctatriene-1,4-diylidene 52, 1,2,4,5,7-cyclooctapentaene 53, and bicyclo[4.1.0]heptatrienyl-1-carbenes 54 and to carbon-skeleton and hydrogen rearrangements of anthryldicarbenes 39 and/or their equivalents at various temperatures. 1,5-Bis[methoxy(trimethylsilyl)methyl]anthracenes (25), prepared from 1,5-diiodoanthracene (63) and methoxytrimethylsilylmethylzinc bromide (57, 2 equiv) as catalyzed by PdCl2(PPh3)2, yield the di-peri-carbenic reaction product 1H,5H-dicyclobuta[de,kl]anthracene (30, >40%) on pyrolysis at 550-650 °C/10-3 mmHg. Proof of structure and various aspects of the mechanisms of formation of 30 are discussed.

Phenyl migrations in dehydroaromatic compounds. A new mechanistic link between alternant and nonalternant hydrocarbons at high temperatures

(Matrix presented) Flash vacuum pyrolysis of benzo[b]biphenylene, an alternant polycyclic aromatic hydrocarbon (PAH), gives fluoranthene, a nonalternant PAH, as the major product at 1100 °C in the gas phase. The most reasonable mechanism to explain this isomerization involves equilibrating diradicals of 2-phenylnaphthalene that rearrange by the net migration of a phenyl group to give equilibrating diradicals of 1-phenylnaphthalene, one isomer of which then cyclizes to fluoranthene.

The ethyne-ethylidene rearrangement: Formation of indeno[2,1-α]indene and fluoranthene on flash vacuum pyrolysis of 1,4-diphenylbutadiyne

Diphenylbutadiyne on flash vacuum pyrolysis at 1120√0.03 Torr gave a pyrolysate (22% mass recovery) consisting of the diyne (7%), indeno[2,1-a]indene (19%), fluoranthene (59%), acephenanthrylene (13%) and aceanthrylene (2%). It is proposed that indeno[1,2-a]indene is formed via 3-phenyl-1,2-didehydronaphthalene and fluoranthene via 1-phenyl-2,3-didehydronaphthalene.