Dibenzopentalene

Dibenzopentalene
Names
	Preferred IUPAC name Indeno[2,1-a]indene
Identifiers
CAS Number	248-58-8 ;
3D model (JSmol)	Interactive image;
ChemSpider	4936522;
PubChem CID	6431184;
UNII	H2UXS49XQ2 ;
CompTox Dashboard (EPA)	DTXSID50424035 ;
	InChI InChI=1S/C16H10/c1-3-7-13-11(5-1)9-15-14-8-4-2-6-12(14)10-16(13)15/h1-10H Key: OZEPXROCWSMGGM-UHFFFAOYSA-N;
	SMILES C1=C2C(=CC3=C2C=CC=C3)C2=CC=CC=C12;
Properties
Chemical formula	C16H10
Molar mass	202.256 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Dibenzopentalene (dibenzo[a,e]pentalene or dibenzo[b,f]pentalene) is an organic compound and a hydrocarbon with formula C₁₆H₁₀. It is of some scientific interest as a stable derivative of the highly reactive antiaromatic pentalene by benzannulation.^[1] The first derivative was synthesised in 1912 by Brand.^[2] The parent compound was reported in 1952.^[3] The NICS value for the 5-membered rings is estimated at 7.4 ppm and that of the six-membered rings -9.8 ppm.^[1] Aromatic dicationic salts can be obtained by reaction with antimony pentafluoride in sulfuryl chloride. The dianion forms by reduction with lithium metal or deprotonation of 5,10-dihydroindeno[2,1-a]indene with two equivalents of butyllithium.^[4]^[5] The aromatic nature of the dianion has been confirmed by X-ray analysis.^[6] Another isomer of this compound exists called dibenzo[a,f]pentalene with one of the benzene rings positioned on the other available pentalene face.

References

^ ^a ^b Saito, Masaichi (2010). "Synthesis and Reactions of Dibenzo\a,e]pentalenes". Symmetry. 2 (2): 950–969. Bibcode:2010Symm....2..950S. doi:10.3390/sym2020950.
^ Brand, K. Über Gefärbte Kohlenwasserstoffe der Diphensuccinden-Reihe. Ber. Detsch. Chem. Ges. 1912, 45, 3071-3077
^ Blood, C. T.; Linstead, R. P. (1952). "422. Fused carbon rings. Part XXI. Dibenzopentalene". Journal of the Chemical Society (Resumed): 2263. doi:10.1039/JR9520002263.
^ Willner, Itamar; Rabinovitz, Mordecai (1978). "1,9-Dimethyldibenzo\b,f]pentalene dication and dianion. New 14.pi. And 18.pi. Aromatic systems". Journal of the American Chemical Society. 100: 337–338. doi:10.1021/ja00469a085.
^ Willner, Itamar; Becker, James Y.; Rabinovitz, Mordecai (1979). "Manifestation of dual aromaticity in doubly charged annelated pentalenes". Journal of the American Chemical Society. 101 (2): 395. doi:10.1021/ja00496a020.
^ Saito, Masaichi; Nakamura, Michio; Tajima, Tomoyuki; Yoshioka, Michikazu (2007). "Reduction of Phenyl Silyl Acetylenes with Lithium: Unexpected Formation of a Dilithium Dibenzopentalenide". Angewandte Chemie International Edition. 46 (9): 1504–7. doi:10.1002/anie.200604067. PMID 17387657.

[saito-1] Saito, Masaichi (2010). "Synthesis and Reactions of Dibenzo\a,e]pentalenes". Symmetry. 2 (2): 950–969. Bibcode:2010Symm....2..950S. doi:10.3390/sym2020950.

[2] Brand, K. Über Gefärbte Kohlenwasserstoffe der Diphensuccinden-Reihe. Ber. Detsch. Chem. Ges. 1912, 45, 3071-3077

[blood-3] Blood, C. T.; Linstead, R. P. (1952). "422. Fused carbon rings. Part XXI. Dibenzopentalene". Journal of the Chemical Society (Resumed): 2263. doi:10.1039/JR9520002263.

[4] Willner, Itamar; Rabinovitz, Mordecai (1978). "1,9-Dimethyldibenzo\b,f]pentalene dication and dianion. New 14.pi. And 18.pi. Aromatic systems". Journal of the American Chemical Society. 100: 337–338. doi:10.1021/ja00469a085.

[5] Willner, Itamar; Becker, James Y.; Rabinovitz, Mordecai (1979). "Manifestation of dual aromaticity in doubly charged annelated pentalenes". Journal of the American Chemical Society. 101 (2): 395. doi:10.1021/ja00496a020.

[6] Saito, Masaichi; Nakamura, Michio; Tajima, Tomoyuki; Yoshioka, Michikazu (2007). "Reduction of Phenyl Silyl Acetylenes with Lithium: Unexpected Formation of a Dilithium Dibenzopentalenide". Angewandte Chemie International Edition. 46 (9): 1504–7. doi:10.1002/anie.200604067. PMID 17387657.

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