:Corannulene

Several synthetic routes exist to corannulene. Flash vacuum pyrolysis techniques generally have lower chemical yields than solution-chemistry syntheses, but offer routes to more derivatives. Corannulene was first isolated in 1966 by multistep organic synthesis.{{Cite journal| doi = 10.1021/ja00954a049| year = 1966| last1 = Barth | first1 = W. E.| title = Dibenzo[ghi,mno]fluoranthene| last2 = Lawton | first2 = R. G.| journal = Journal of the American Chemical Society| volume = 88| issue = 2| pages = 380–381 }} In 1971, the synthesis and properties of corannulane were reported.{{cite journal|last1=Lawton|first1=Richard G.|last2=Barth|first2=Wayne E.|title=Synthesis of corannulene|journal=Journal of the American Chemical Society|date=April 1971|volume=93|issue=7|pages=1730–1745|doi=10.1021/ja00736a028|s2cid=94872875 }} A flash vacuum pyrolysis method followed in 1991.{{Cite journal| last4 = Warren | first3 = D. T. | first4 = H. B.| journal = Journal of the American Chemical Society| pages = 7082–7084| volume = 113| doi = 10.1021/ja00018a082| last3 = Meyer| year = 1991| title = Corannulene. A convenient new synthesis | first2 = M. M.| last1 = Scott | first1 = L. T.| last2 = Hashemi| issue = 18 }} One synthesis based on solution chemistry{{Cite journal| doi = 10.1021/ja0011461| title = A Practical, Large Scale Synthesis of the Corannulene System| year = 2000| last1 = Sygula | first1 = A.| last2 = Rabideau | first2 = P. W.| journal = Journal of the American Chemical Society| volume = 122| issue = 26| pages = 6323–6324 }} consists of a nucleophilic displacement–elimination reaction of an octabromide with sodium hydroxide:

:File:Corannulene synthesis Sygula 2000.svg

The bromine substituents are removed with an excess of n-butyllithium.

A kilogram scale synthesis of corannulene has been achieved.{{Cite journal| doi = 10.1021/op200387s| title = Kilogram-Scale Production of Corannulene| year = 2012| last1 = Butterfield | first1 = A.| last2 = Gilomen | first2 = B.| last3 = Siegel | first3 = J.| journal = Organic Process Research & Development| volume = 16| issue = 4| pages = 664–676 }}

Much effort is directed at functionalization of the corannulene ring with novel functional groups such as ethynyl groups,{{Cite journal| doi = 10.1021/ja802334n| pmid = 18642812| year = 2008| last1 = Wu | first1 = Y.| last2 = Bandera | first2 = D.| last3 = Maag | first3 = R.| last4 = Linden | first4 = A.| last5 = Baldridge | first5 = K.| last6 = Siegel | first6 = J.| title = Multiethynyl corannulenes: synthesis, structure, and properties| volume = 130| issue = 32| pages = 10729–10739| journal = Journal of the American Chemical Society }}{{Cite journal| doi = 10.1039/b705621d| pmid = 17637965| year = 2007| last1 = Mack | first1 = J.| last2 = Vogel | first2 = P.| last3 = Jones | first3 = D.| last4 = Kaval | first4 = N.| last5 = Sutton | first5 = A.| title = The development of corannulene-based blue emitters| volume = 5| issue = 15| pages = 2448–2452| journal = Organic & Biomolecular Chemistry}} ether groups,{{Cite journal| doi = 10.1021/ol902352k| pmid = 19905024| year = 2009| last1 = Gershoni-Poranne | first1 = R.| last2 = Pappo | first2 = D.| last3 = Solel | first3 = E.| last4 = Keinan | first4 = E.| title = Corannulene ethers via Ullmann condensation| volume = 11| issue = 22| pages = 5146–5149| journal = Organic Letters }} thioether groups,{{Cite journal| doi = 10.1039/b919616a| pmid = 20024131| year = 2010| last1 = Baldridge | first1 = K.| last2 = Hardcastle | first2 = K.| last3 = Seiders | first3 = T.| last4 = Siegel | first4 = J.| title = Synthesis, structure and properties of decakis(phenylthio)corannulene| volume = 8| issue = 1| pages = 53–55| journal = Organic & Biomolecular Chemistry }} platinum functional groups,{{Cite journal| doi = 10.1016/j.jorganchem.2009.07.015| title = Synthesis and structure of penta-platinum σ-bonded derivatives of corannulene| year = 2009| last1 = Choi | first1 = H.| last2 = Kim | first2 = C.| last3 = Park | first3 = K. M.| last4 = Kim | first4 = J.| last5 = Kang | first5 = Y.| last6 = Ko | first6 = J.| journal = Journal of Organometallic Chemistry| volume = 694| issue = 22| pages = 3529–3532 }} aryl groups,{{Cite journal| doi = 10.1021/ol8028127| pmid = 19193048| year = 2009| last1 = Pappo | first1 = D.| last2 = Mejuch | first2 = T.| last3 = Reany | first3 = O.| last4 = Solel | first4 = E.| last5 = Gurram | first5 = M.| last6 = Keinan | first6 = E.| title = Diverse Functionalization of Corannulene: Easy Access to Pentagonal Superstructure| journal = Organic Letters| volume = 11| issue = 5| pages = 1063–1066 }} phenalenyl fused {{Cite journal | first8 = T.| last9 = Nakasuji| last8 = Takui | first7 = K.| last7 = Sato | first9 = K.| title = Curve-structured phenalenyl chemistry: synthesis, electronic structure, and bowl-inversion barrier of a phenalenyl-fused corannulene anion| journal = Journal of the American Chemical Society| pages = 14954–14955| issue = 45| volume = 130 | first6 = K.| last6 = Ogasawara | first1 = S.| last2 = Morita| last1 = Nishida| year = 2008| pmid = 18937470 | first2 = Y.| last3 = Ueda| last5 = Fukui | first5 = K. | first4 = T.| last4 = Kobayashi | first3 = A.| doi = 10.1021/ja806708j }} and indeno extensions.{{Cite journal| doi = 10.1021/ja9031852| pmid = 19722628| year = 2009| last1 = Steinberg | first1 = B.| last2 = Jackson | first2 = E.| last3 = Filatov | first3 = A.| last4 = Wakamiya | first4 = A.| last5 = Petrukhina | first5 = M.| last6 = Scott | first6 = L.| title = Aromatic pi-systems more curved than C(60). The complete family of all indenocorannulenes synthesized by iterative microwave-assisted intramolecular arylations| volume = 131| issue = 30| pages = 10537–10545| journal = Journal of the American Chemical Society }} and ferrocene groups.{{cite journal | last1 = Topolinski | first1 = Berit | last2 = Schmidt | first2 = Bernd M. | last3 = Kathan | first3 = Michael | last4 = Troyanov | first4 = Sergej I. | last5 = Lentz | first5 = Dieter | year = 2012 | title = Corannulenylferrocenes: towards a 1D, non-covalent metal–organic nanowire | journal = Chem. Commun. | volume = 48 | issue = 50| pages = 6298–6300 | doi = 10.1039/C2CC32275G | pmid = 22595996 }}

The observed aromaticity for this compound is explained with a so-called annulene-within-an-annulene model. According to this model corannulene is made up of an aromatic 6 electron cyclopentadienyl anion surrounded by an aromatic 14 electron {{chem name|annulenyl}} cation. This model was suggested by Barth and Lawton in the first synthesis of corannulene in 1966. They also suggested the trivial name 'corannulene', which is derived from the annulene-within-an-annulene model: core + annulene.

:File:Corannulenres.png

However, later theoretical calculations have disputed the validity of this approximation.{{Cite journal | doi = 10.1016/0166-1280(94)03961-J | title = Structure and inversion barriers of corannulene, its dianion and tetraanion. An ab initio study | first2 = P. W. | year = 1995 | last2 = Rabideau | last1 = Sygula | first1 = A. | journal = Journal of Molecular Structure: THEOCHEM | volume = 333 | issue = 3 | pages = 215–226 }}{{Cite journal| doi = 10.1021/jp8038779| pmid = 18693706| year = 2008| last1 = Monaco | first1 = G.| last2 = Scott | first2 = L.| last3 = Zanasi | first3 = R.| title = Magnetic euripi in corannulene| volume = 112| issue = 35| pages = 8136–8147| journal = The Journal of Physical Chemistry A | bibcode = 2008JPCA..112.8136M}}

Corannulene can be reduced up to a tetraanion in a series of one-electron reductions. This has been performed with alkali metals, electrochemically and with bases. The corannulene dianion is antiaromatic and tetraanion is again aromatic. With lithium as reducing agent two tetraanions form a supramolecular dimer with two bowls stacked into each other with 4 lithium ions in between and 2 pairs above and below the stack.{{Cite journal| doi = 10.1126/science.265.5175.1065| pmid = 17832895| year = 1994| last1 = Ayalon | first1 = A.| last2 = Sygula | first2 = A.| last3 = Cheng | first3 = P.| last4 = Rabinovitz | first4 = M.| last5 = Rabideau | first5 = P.| last6 = Scott | first6 = L.| title = Stable High-Order Molecular Sandwiches: Hydrocarbon Polyanion Pairs with Multiple Lithium Ions Inside and out| volume = 265| issue = 5175| pages = 1065–1067| journal = Science |bibcode = 1994Sci...265.1065A | s2cid = 4979579}} This self-assembly motif was applied in the organization of fullerenes. Penta-substituted fullerenes (with methyl or phenyl groups) charged with five electrons form supramolecular dimers with a complementary corannulene tetraanion bowl, 'stitched' by interstitial lithium cations.{{Cite journal| doi = 10.1021/ja0515102| pmid = 15984885| year = 2005| last1 = Aprahamian | first1 = I.| last2 = Eisenberg | first2 = D.| last3 = Hoffman | first3 = R.| last4 = Sternfeld | first4 = T.| last5 = Matsuo | first5 = Y.| last6 = Jackson | first6 = E.| last7 = Nakamura | first7 = E.| last8 = Scott | first8 = L.| last9 = Sheradsky | first9 = T.| last10 = Rabinovitz | first10 = M.| title = Ball-and-socket stacking of supercharged geodesic polyarenes: bonding by interstitial lithium ions| volume = 127| issue = 26| pages = 9581–9587| journal = Journal of the American Chemical Society }} In a related system 5 lithium ions are sandwiched between two corannulene bowls {{cite journal | doi = 10.1126/science.1208686 | volume=333 | title=A Main Group Metal Sandwich: Five Lithium Cations Jammed Between Two Corannulene Tetraanion Decks | year=2011 | journal=Science | pages=1008–1011 | last1 = Zabula | first1 = A. V.| issue=6045 | pmid=21852497 | bibcode=2011Sci...333.1008Z | s2cid=1125747 }}

In one cyclopenta[bc]corannulene a concave - concave aggregate is observed by NMR spectroscopy with 2 C–Li–C bonds connecting the tetraanions.{{Cite journal| doi = 10.1021/jo051949c| pmid = 16388648| year = 2006| last1 = Aprahamian | first1 = I.| last2 = Preda | first2 = D.| last3 = Bancu | first3 = M.| last4 = Belanger | first4 = A.| last5 = Sheradsky | first5 = T.| last6 = Scott | first6 = L.| last7 = Rabinovitz | first7 = M.| title = Reduction of bowl-shaped hydrocarbons: dianions and tetraanions of annelated corannulenes| volume = 71| issue = 1| pages = 290–298| journal = The Journal of Organic Chemistry }}

:Image:Cyclopenta-bc-corannulene.png{{clear}}

Metals tend to bind to the convex face of the annulene. Concave binding has been reported for a cesium / crown ether system {{cite journal | last1 = Spisak | first1 = S. N. | last2 = Zabula | first2 = A. V. | last3 = Filatov | first3 = A. S. | last4 = Rogachev | first4 = A. Y. | last5 = Petrukhina | first5 = M. A. | year = 2011 | title = Selective Endo and Exo Binding of Alkali Metals to Corannulene | journal = Angewandte Chemie International Edition | volume = 50 | issue = 35| pages = 8090–8094 | doi = 10.1002/anie.201103028 | pmid=21748832 }}

UV 193-nm photoionization effectively removes a π-electron from the twofold degenerate E₁-HOMO located in the aromatic network of electrons yielding a corannulene radical cation.{{cite journal|last=Galué|first=Héctor Alvaro|author2=Rice, Corey A. |author3=Steill, Jeffrey D. |author4=Oomens, Jos |title=Infrared spectroscopy of ionized corannulene in the gas phase|journal=The Journal of Chemical Physics|date=1 January 2011|volume=134|issue=5|pages=054310|doi=10.1063/1.3540661|pmid=21303123|bibcode = 2011JChPh.134e4310G |url=https://pure.uva.nl/ws/files/1233463/94290_345138.pdf}} Owing to the degeneracy in the HOMO orbital, the corannulene radical cation is unstable in its original C_5v molecular arrangement, and therefore, subject to Jahn-Teller (JT) vibronic distortion.

Using electrospray ionization, a protonated corannulene cation has been produced in which the protonation site was observed to be on a peripheral sp²-carbon atom.

Corannulene can react with electrophiles to form a corannulene carbocation. Reaction with chloromethane and aluminium chloride results in the formation of an AlCl₄⁻ salt with a methyl group situated at the center with the cationic center at the rim. X-ray diffraction analysis shows that the new carbon-carbon bond is elongated (157 pm) {{cite journal | last1 = Zabula | first1 = A. V. | last2 = Spisak | first2 = S. N. | last3 = Filatov | first3 = A. S. | last4 = Rogachev | first4 = A. Y. | last5 = Petrukhina | first5 = M. A. | year = 2011 | title = A Strain-Releasing Trap for Highly Reactive Electrophiles: Structural Characterization of Bowl-Shaped Arenium Carbocations | journal = Angewandte Chemie International Edition | volume = 50 | issue = 13 | pages = 2971–2974 | doi = 10.1002/anie.201007762 | pmid = 21404379 }}

Bicorannulenyl is the product of dehydrogenative coupling of corannulene. With the formula C₂₀H₉-C₂₀H₉, it consists of two corannulene units connected through a single C-C bond. The molecule's stereochemistry consists of two chiral elements: the asymmetry of a singly substituted corannulenyl, and the helical twist about the central bond. In the neutral state, bicorannulenyl exists as 12 conformers, which interconvert through multiple bowl-inversions and bond-rotations.{{Cite journal| doi = 10.1021/jo800359z| pmid = 18505292| year = 2008| last1 = Eisenberg | first1 = D.| last2 = Filatov | first2 = A.| last3 = Jackson | first3 = E.| last4 = Rabinovitz | first4 = M.| last5 = Petrukhina | first5 = M.| last6 = Scott | first6 = L.| last7 = Shenhar | first7 = R.| title = Bicorannulenyl: stereochemistry of a C40H18 biaryl composed of two chiral bowls| volume = 73| issue = 16| pages = 6073–6078| journal = The Journal of Organic Chemistry }}

When bicorannulenyl is reduced to a dianion with potassium metal, the central bond assumes significant double-bond character. This change is attributed to the orbital structure, which has a LUMO orbital localized on the central bond.{{cite journal | last1 = Eisenberg | first1 = D. | last2 = Quimby | first2 = J. M. | last3 = Jackson | first3 = E. A. | last4 = Scott | first4 = L. T. | last5 = Shenhar | first5 = R. | year = 2010 | title = The Bicorannulenyl Dianion: A Charged Overcrowded Ethylene | journal = Angewandte Chemie International Edition | volume = 49 | issue = 41| pages = 7538–7542 | doi = 10.1002/anie.201002515 | pmid=20814993 }} When bicorannulenyl is reduced to an {{chem name|octaanion}} with lithium metal, it self-assembles into supramolecular oligomers.{{cite journal | last1 = Eisenberg | first1 = D. | last2 = Quimby | first2 = J. M. | last3 = Jackson | first3 = E. A. | last4 = Scott | first4 = L. T. | last5 = Shenhar | first5 = R. | year = 2010 | title = Highly Charged Supramolecular Oligomers Based on the Dimerization of Corannulene Tetraanion | journal = Chemical Communications | volume = 46 | issue = 47| pages = 9010–9012 | doi = 10.1039/c0cc03965a | pmid = 21057679 }} This motif illustrates "charged polyarene stacking".

File:Buckycatcher JACS 2007 V129 p3843.jpgThe corannulene group is used in host–guest chemistry with interactions based on pi stacking, notably with fullerenes (the {{chem name|buckycatcher}}) {{Cite journal| doi = 10.1021/ja070616p| pmid = 17348661| year = 2007| last1 = Sygula | first1 = A.| last2 = Fronczek | first2 = F.| last3 = Sygula | first3 = R.| last4 = Rabideau | first4 = P.| last5 = Olmstead | first5 = M.| title = A double concave hydrocarbon buckycatcher| volume = 129| issue = 13| pages = 3842–3843| journal = Journal of the American Chemical Society | s2cid = 25154754}}{{Cite journal| doi = 10.1002/jcc.21022| pmid = 18504779| year = 2009| last1 = Wong | first1 = B. M.| title = Noncovalent interactions in supramolecular complexes: a study on corannulene and the double concave buckycatcher| volume = 30| issue = 1| pages = 51–56| journal = Journal of Computational Chemistry | arxiv = 1004.4243| s2cid = 18247078}} but also with nitrobenzene{{Cite journal| doi = 10.1016/j.tetlet.2009.09.177| title = Molecular clips and tweezers with corannulene pincers| year = 2009| last1 = Kobryn | first1 = L.| last2 = Henry | first2 = W. P.| last3 = Fronczek | first3 = F. R.| last4 = Sygula | first4 = R.| last5 = Sygula | first5 = A.| journal = Tetrahedron Letters| volume = 50| issue = 51| pages = 7124–7127 }}

Alkyl-substituted corannulenes form a thermotropic hexagonal columnar liquid crystalline mesophase.{{Cite journal | first7 = M.| last8 = Aida| last7 = Takata | first6 = K.| last6 = Kato | first8 = T.| title = Liquid crystalline corannulene responsive to electric field| journal = Journal of the American Chemical Society| pages = 44–45| issue = 1| volume = 131 | first5 = J.| last5 = Kim | first1 = D.| last1 = Miyajima| year = 2009| pmid = 19128171| last2 = Tashiro | first2 = K. | first4 = H.| last4 = Takezoe | first3 = F.| last3 = Araoka| doi = 10.1021/ja808396b }} Corannulene has also been used as the core group in a dendrimer. Like other PAHs, corannulene ligates metals.{{cite journal | last1 = Seiders | first1 = T. Jon | last2 = Baldridge | first2 = Kim K. | last3 = O'Connor | first3 = Joseph M. | last4 = Siegel | first4 = Jay S. | year = 1997 | title = Hexahapto Metal Coordination to Curved Polyaromatic Hydrocarbon Surfaces: The First Transition Metal Corannulene Complex | journal = J. Am. Chem. Soc. | volume = 119 | issue = 20| pages = 4781–4782 | doi = 10.1021/ja964380t }}{{cite journal | last1 = Siegel | first1 = Jay S. | last2 = Baldridge | first2 = Kim K. | last3 = Linden | first3 = Anthony | last4 = Dorta | first4 = Reto | year = 2006 | title = d8 Rhodium and Iridium Complexes of Corannulene | journal = J. Am. Chem. Soc. | volume = 128 | issue = 33| pages = 10644–10645 | doi = 10.1021/ja062110x | pmid=16910635}}{{Cite journal| doi = 10.1002/anie.200704783| pmid = 18214869| year = 2008| last1 = Petrukhina | first1 = M. A.| title = Coordination of buckybowls: the first concave-bound metal complex| volume = 47| issue = 9| pages = 1550–1552| journal = Angewandte Chemie International Edition in English }}{{Cite journal| doi = 10.1021/om0610795| title = η6-Coordination of the Curved Carbon Surface of Corannulene (C20H10) to (η6-arene)M2+(M = Ru, Os)| year = 2007| last1 = Zhu | first1 = B.| last2 = Ellern | first2 = A.| last3 = Sygula | first3 = A.| last4 = Sygula | first4 = R.| last5 = Angelici | first5 = R. J.| journal = Organometallics| volume = 26| issue = 7| pages = 1721–1728 }}{{Cite journal| doi = 10.1021/om060350f| title = Corannulene: A Preference forexo-Metal Binding. X-ray Structural Characterization of [Ru2(O2CCF3)2(CO)4·(η2-C20H10)2]| year = 2006| last1 = Petrukhina | first1 = M. A.| last2 = Sevryugina | first2 = Y.| last3 = Rogachev | first3 = A. Y.| last4 = Jackson | first4 = E. A.| last5 = Scott | first5 = L. T.| journal = Organometallics| volume = 25| issue = 22| pages = 5492–5495 }}{{Cite journal| doi = 10.1021/ja062110x| pmid = 16910635| year = 2006| last1 = Siegel | first1 = J.| last2 = Baldridge | first2 = K.| last3 = Linden | first3 = A.| last4 = Dorta | first4 = R.| title = D8 rhodium and iridium complexes of corannulene| volume = 128| issue = 33| pages = 10644–10645| journal = Journal of the American Chemical Society }}{{cite journal | last1 = Bandera | first1 = D. | last2 = Baldridge | first2 = K. K. | last3 = Linden | first3 = A. | last4 = Dorta | first4 = R. | last5 = Siegel | first5 = J. S. | year = 2011 | title = Stereoselective Coordination of C5-Symmetric Corannulene Derivatives with an Enantiomerically Pure [RhI(nbd*)] Metal Complex. | journal = Angewandte Chemie International Edition | volume = 50 | issue = 4 | pages = 865–867 | doi = 10.1002/anie.201006877 | pmid = 21246679 }} Corannulenes with ethynyl groups are investigated for their potential use as blue emitters. The structure was analyzed by infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy.{{Cite journal|last1=Diana|first1=Nooramalina|last2=Yamada|first2=Yasuhiro|last3=Gohda|first3=Syun|last4=Ono|first4=Hironobu|last5=Kubo|first5=Shingo|last6=Sato|first6=Satoshi|date=2021-02-01|title=Carbon materials with high pentagon density|url=https://doi.org/10.1007/s10853-020-05392-x|journal=Journal of Materials Science|language=en|volume=56|issue=4|pages=2912–2943|doi=10.1007/s10853-020-05392-x|bibcode=2021JMatS..56.2912D|s2cid=224784081|issn=1573-4803|url-access=subscription}}

{{clear}}

{{Commons category|Corannulene}}

{{wiktionary}}

• Coronene
• Helicene
• Geodesic polyarene

{{Reflist|2}}

{{PAHs}}

Category:Geodesic polyarenes

Category:Polycyclic aromatic hydrocarbons