Biphenylene

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Biphenylene
Biphenylene saftig.png
Biphenylene-from-xtal-3D-vdW.png
Names
Preferred IUPAC name
Biphenylene [1]
Other names
Diphenylene
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.217.287 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/C12H8/c1-2-6-10-9(5-1)11-7-3-4-8-12(10)11/h1-8H Yes check.svgY
    Key: IFVTZJHWGZSXFD-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C12H8/c1-2-6-10-9(5-1)11-7-3-4-8-12(10)11/h1-8H
    Key: IFVTZJHWGZSXFD-UHFFFAOYAR
  • c1ccc-2c(c1)-c3c2cccc3
Properties
C12H8
Molar mass 152.196 g·mol−1
AppearanceSolid
Melting point 109 to 111 °C (228 to 232 °F; 382 to 384 K)
Related compounds
benzene
biphenyl
cyclobutene
cyclobutadiene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Biphenylene is an organic compound with the formula (C6H4)2. It is a pale, yellowish solid with a hay-like odor. Despite its unusual structure, it behaves like a traditional polycyclic aromatic hydrocarbon. [2] [3]

Contents

Bonding

Biphenylene is a polycyclic hydrocarbon, composed of two benzene rings joined by two bridging bonds (as opposed to a normal ring fusion), thus forming a 6-4-6 arene system. The resulting planar structure [4] was one of the first π-electronic hydrocarbon systems discovered to show evidence of antiaromaticity. The spectral and chemical properties show the influence of the central [4n] ring, leading to considerable interest in the system in terms of its degree of lessened aromaticity. Questions of bond alternation and ring currents have been investigated repeatedly. Both X-ray diffraction [5] and electron diffraction [6] studies show a considerable alternation of bond lengths, with the bridging bonds between the benzenoid rings having the unusually great length of 1.524 Å. The separation of the rings is also reflected by the absence of the transmission of NMR substituent effects through the central [4n] ring. However, more sensitive NMR evidence, and particularly the shifting of proton resonances to high field, does indicate the existence of electron delocalization in the central [4n] ring. [7] [8] This upfield shift has been interpreted in terms of diminished benzenoid ring currents, either with or without an accompanying paramagnetic ring current in the central [4n] ring. Magnetic susceptibility measurements also show a diminishing of both diamagnetic exaltation and diamagnetic anisotropy, relative to comparable pure [4n+2] systems, which is also consistent with a reduction of ring current diamagnetism. [9] [10] The electronic structure of biphenylene in the gas phase has the HOMO at a binding energy of 7.8 eV. [11]

Preparation

Biphenylene was first synthesized by Lothrop in 1941. [12] The biphenylene structure can also be understood as a dimer of the reactive intermediate benzyne, which in fact serves as a major synthetic route, by heating the benzenediazonium-2-carboxylate zwitterion prepared from 2-aminobenzoic acid. [13] Another approach is by N-amination of 1H-benzotriazole with hydroxylamine-O-sulfonic acid. The major product, 1-aminobenzotriazole, forms benzyne in an almost quantitative yield by oxidation with lead(IV) acetate, which rapidly dimerises to biphenylene in good yields. [14]

Synthesis of Benzyne and Biphenylene from 1H-Benzotriazole Dehydrobenzol aus Aminobenztriazol.svg
Synthesis of Benzyne and Biphenylene from 1H-Benzotriazole

Higher biphenylenes

Polycycles containing the biphenylene nucleus have also been prepared, some having considerable antiaromatic character. [15] [16] [17] [18] [19] In general, additional 6-membered rings add further aromatic character, and additional 4-membered and 8-membered rings add antiaromatic character. However, the exact natures of the additions and fusions greatly affect the perturbations of the biphenylene system, with many fusions resulting in counter-intuitive stabilization by [4n] rings, or destabilization by 6-membered rings. This has led to significant interest in the systems by theoretical chemists and graph theoreticians. Even a complete 2-dimensional carbon sheet with biphenylene-like subunits has been proposed [20] and was in-depth investigated by theoretical means, finding a technologically relevant direct band gap of ca. 1 eV, excitonic binding energies of ca. 500 meV and potential as a gas sensor. [21] [22] [23]

Network

Researchers synthesized a biphenylene sheet consisting of sp2-hybridized carbon atoms that formed four-, six-, and eight-membered rings on a smooth gold surface. A bottom-up two-step interpolymer dehydrofluorination of an adsorbed halogenated terphenyl molecule polymerization yielded ultraflat four- and eight-membered rings. The resulting allotrope was metallic. [24]

Related Research Articles

<span class="mw-page-title-main">Aromaticity</span> Chemical property

In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected by the stabilization of conjugation alone. The earliest use of the term was in an article by August Wilhelm Hofmann in 1855. There is no general relationship between aromaticity as a chemical property and the olfactory properties of such compounds.

<span class="mw-page-title-main">Hückel's rule</span> Method of determining aromaticity in organic molecules

In organic chemistry, Hückel's rule predicts that a planar ring molecule will have aromatic properties if it has 4n + 2 π electrons, where n is a non-negative integer. The quantum mechanical basis for its formulation was first worked out by physical chemist Erich Hückel in 1931. The succinct expression as the 4n + 2 rule has been attributed to W. v. E. Doering (1951), although several authors were using this form at around the same time.

Antiaromaticity is a chemical property of a cyclic molecule with a π electron system that has higher energy, i.e., it is less stable due to the presence of 4n delocalised electrons in it, as opposed to aromaticity. Unlike aromatic compounds, which follow Hückel's rule and are highly stable, antiaromatic compounds are highly unstable and highly reactive. To avoid the instability of antiaromaticity, molecules may change shape, becoming non-planar and therefore breaking some of the π interactions. In contrast to the diamagnetic ring current present in aromatic compounds, antiaromatic compounds have a paramagnetic ring current, which can be observed by NMR spectroscopy.

<span class="mw-page-title-main">Pentalene</span> Chemical compound

Pentalene is a polycyclic hydrocarbon composed of two fused cyclopentadiene rings. It has chemical formula C8H6. It is antiaromatic, because it has 4n π electrons where n is any integer. For this reason it dimerizes even at temperatures as low as −100 °C. The derivative 1,3,5-tri-tert-butylpentalene was synthesized in 1973. Because of the tert-butyl substituents this compound is thermally stable. Pentalenes can also be stabilized by benzannulation for example in the compounds benzopentalene and dibenzopentalene.

In organic chemistry, arynes and benzynes are a class of highly reactive chemical species derived from an aromatic ring by removal of two substituents. Arynes are examples of didehydroarenes, although 1,3- and 1,4-didehydroarenes are also known. Arynes are examples of alkynes under high strain.

An alkyne trimerisation is a [2+2+2] cycloaddition reaction in which three alkyne units react to form a benzene ring. The reaction requires a metal catalyst. The process is of historic interest as well as being applicable to organic synthesis. Being a cycloaddition reaction, it has high atom economy. Many variations have been developed, including cyclisation of mixtures of alkynes and alkenes as well as alkynes and nitriles.

<span class="mw-page-title-main">Sumanene</span> Chemical compound

Sumanene is a polycyclic aromatic hydrocarbon and of scientific interest because the molecule can be considered a fragment of buckminsterfullerene. Suman means "sunflower" in both Hindi and Sanskrit. The core of the arene is a benzene ring and the periphery consists of alternating benzene rings (3) and cyclopentadiene rings (3). Unlike fullerene, sumanene has benzyl positions which are available for organic reactions.

<span class="mw-page-title-main">Cyclooctadecanonaene</span> Chemical compound

Cyclooctadecanonaene or [18]annulene is an organic compound with chemical formula C
18H
18. It belongs to the class of highly conjugated compounds known as annulenes and is aromatic. The usual isomer that [18]annulene refers to is the most stable one, containing six interior hydrogens and twelve exterior ones, with the nine formal double bonds in the cis,trans,trans,cis,trans,trans,cis,trans,trans configuration. It is reported to be a red-brown crystalline solid.

<span class="mw-page-title-main">Annulyne</span>

Annulynes or dehydroannulenes are conjugated monocyclic hydrocarbons with alternating single and double bonds in addition to at least one triple bond.

<span class="mw-page-title-main">Aromatic ring current</span> Electric current observed in aromatic compounds

An aromatic ring current is an effect observed in aromatic molecules such as benzene and naphthalene. If a magnetic field is directed perpendicular to the plane of the aromatic system, a ring current is induced in the delocalized π electrons of the aromatic ring. This is a direct consequence of Ampère's law; since the electrons involved are free to circulate, rather than being localized in bonds as they would be in most non-aromatic molecules, they respond much more strongly to the magnetic field.

<span class="mw-page-title-main">Homoaromaticity</span> Organic molecular structure

Homoaromaticity, in organic chemistry, refers to a special case of aromaticity in which conjugation is interrupted by a single sp3 hybridized carbon atom. Although this sp3 center disrupts the continuous overlap of p-orbitals, traditionally thought to be a requirement for aromaticity, considerable thermodynamic stability and many of the spectroscopic, magnetic, and chemical properties associated with aromatic compounds are still observed for such compounds. This formal discontinuity is apparently bridged by p-orbital overlap, maintaining a contiguous cycle of π electrons that is responsible for this preserved chemical stability.

<span class="mw-page-title-main">Hexacene</span> Chemical compound

Hexacene is an aromatic compound consisting of six linearly-fused benzene rings. It is a blue-green, air-stable solid with low solubility.

<span class="mw-page-title-main">Tricyclobutabenzene</span> Chemical compound

Tricyclobutabenzene is an aromatic hydrocarbon consisting of a benzene core with three cyclobutane rings fused onto it. This compound and related compounds are studied in the laboratory because they are often displaying unusual conformations and because of their unusual reactivity. Tricyclobutabenzenes are isomers of radialenes and form an equilibrium with them.

<span class="mw-page-title-main">Möbius aromaticity</span>

In organic chemistry, Möbius aromaticity is a special type of aromaticity believed to exist in a number of organic molecules. In terms of molecular orbital theory these compounds have in common a monocyclic array of molecular orbitals in which there is an odd number of out-of-phase overlaps, the opposite pattern compared to the aromatic character to Hückel systems. The nodal plane of the orbitals, viewed as a ribbon, is a Möbius strip, rather than a cylinder, hence the name. The pattern of orbital energies is given by a rotated Frost circle (with the edge of the polygon on the bottom instead of a vertex), so systems with 4n electrons are aromatic, while those with 4n + 2 electrons are anti-aromatic/non-aromatic. Due to incrementally twisted nature of the orbitals of a Möbius aromatic system, stable Möbius aromatic molecules need to contain at least 8 electrons, although 4 electron Möbius aromatic transition states are well known in the context of the Dewar-Zimmerman framework for pericyclic reactions. Möbius molecular systems were considered in 1964 by Edgar Heilbronner by application of the Hückel method, but the first such isolable compound was not synthesized until 2003 by the group of Rainer Herges. However, the fleeting trans-C9H9+ cation, one conformation of which is shown on the right, was proposed to be a Möbius aromatic reactive intermediate in 1998 based on computational and experimental evidence.

Cyclotetradecaheptaene, often referred to as [14]annulene, is a hydrocarbon with molecular formula C14H14, which played an important role in the development of criteria (Hückel's rule) for aromaticity, a stabilizing property of central importance in physical organic chemistry. It forms dark-red needle-like crystals.

<span class="mw-page-title-main">E. D. Jemmis</span> Indian theoretical chemist

Eluvathingal Devassy Jemmis is a professor of theoretical chemistry at the Indian Institute of Science, Bangalore, India. He was the founding director of Indian Institute of Science Education and Research, Thiruvananthapuram (IISER-TVM). His primary area of research is applied theoretical chemistry with emphasis on structure, bonding and reactivity, across the periodic table of the elements. Apart from many of his contributions to applied theoretical chemistry, an equivalent of the structural chemistry of carbon, as exemplified by the Huckel 4n+2 Rule, benzenoid aromatics and graphite, and tetrahedral carbon and diamond, is brought in the structural chemistry of boron by the Jemmis mno rules which relates polyhedral and macropolyhedral boranes to allotropes of boron and boron-rich solids. He has been awarded Padma Shri in Science and Engineering category by the Government of India.

In organic chemistry, Baird's rule estimates whether the lowest triplet state of planar, cyclic structures will have aromatic properties or not. The quantum mechanical basis for its formulation was first worked out by physical chemist N. Colin Baird at the University of Western Ontario in 1972.

<span class="mw-page-title-main">1,6-Methano(10)annulene</span> Chemical compound

1,6-Methano[10]annulene (also known as 1,6-methanonaphthalene or homonaphthalene) is an aromatic hydrocarbon with chemical formula C11H10. It was the first stable aromatic compound based on the cyclodecapentaene system to be discovered.

<span class="mw-page-title-main">Butalene</span> Chemical compound

Butalene is a polycyclic hydrocarbon composed of two fused cyclobutadiene rings. A reported possible synthesis of it involves an elimination reaction from a Dewar benzene derivative. The structure itself can be envisioned as benzene with an internal bridge, and calculations indicate it is somewhat less stable than the open 1,4-didehydrobenzene biradical, the valence isomer in which that bridged bond is broken.

<span class="mw-page-title-main">Atsuhiro Osuka</span>

Atsuhiro Osuka is a research professor of organic chemistry in the Department of Chemistry, Graduate School of Science, Kyoto University (Japan). He is recognized in the fields of porphyrinoid chemistry for his works in extended π-electron systems and its tunable aromatic behaviors.

References

  1. ↑ "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 209. doi:10.1039/9781849733069-FP001. ISBN   978-0-85404-182-4.
  2. ↑ Cava, M. P.; Mitchell, M. J. (1967). "10". Cyclobutadiene and Related Compounds. Academic Press. pp. 255–316.
  3. ↑ Barton, J. W. (1969). "2". In J. P. Snyder (ed.). Nonbenzenoid Aromatics. Vol. 1. Academic Press. pp. 32–62.
  4. ↑ Waser, Jurg; Lu, Chia-Si (1944). "The Crystal Structure of Biphenylene". J. Am. Chem. Soc. 66 (12): 2035–2042. doi:10.1021/ja01240a012.
  5. ↑ Fawcett, J. K.; Trotter, J. (1966). "A refinement of the structure of biphenylene". Acta Crystallogr. 20 (1): 87–93. Bibcode:1966AcCry..20...87F. doi: 10.1107/s0365110x66000161 .
  6. ↑ Yokozeki, A.; Wilcox Jr., C. F.; Bauer, S. H. (1974). "Biphenylene. Internuclear distances and their root mean square amplitudes of vibration". J. Am. Chem. Soc. 96 (4): 1026–1032. doi:10.1021/ja00811a014.
  7. ↑ Katritzky, A. R.; Reavill, R. E. (1964). "Nuclear magnetic resonance evidence for partial bond fixation in biphenylene". Recl. Trav. Chim. Pays-Bas . 83 (12): 1230–1232. doi:10.1002/recl.19640831203.
  8. ↑ Fraenkel, G.; Asahi, Y.; Mitchell, M. J.; Cava, M. P. (1964). "NMR spectroscopy of benzocyclobutene and biphenylene". Tetrahedron . 20 (5): 1179–1184. doi:10.1016/s0040-4020(01)98985-9.
  9. ↑ Dauben Jr., Hyp. J.; Wilson, James D.; Laity, John L. (1969). "Diamagnetic susceptibility exaltation in hydrocarbons". J. Am. Chem. Soc. 91 (8): 1991–1998. doi:10.1021/ja01036a022.
  10. ↑ Anet, F. A. L.; Schenck, G. (1971). "Application of solvent effects to the study of diamagnetic and paramagnetic ring currents". J. Am. Chem. Soc. 93 (2): 556–557. doi:10.1021/ja00731a061.
  11. ↑ Lüder, Johann; de Simone, Monica; Totani, Roberta; et al. (2015). "The electronic characterization of biphenylene—Experimental and theoretical insights from core and valence level spectroscopy" (PDF). J. Chem. Phys. 142 (7): 074305. Bibcode:2015JChPh.142g4305L. doi:10.1063/1.4907723. hdl: 11368/2842819 . PMID   25702013.
  12. ↑ Lothrop, W. C. (1941). "Biphenylene". J. Am. Chem. Soc. 63 (5): 1187–1191. doi:10.1021/ja01850a007.
  13. ↑ Logullo, Francis M.; Seitz, Arnold M.; Friedman, Lester (1968). "Benzenediazonium-2-Carboxylate and Biphenylene (Benzenediazonium, o-carboxy-, hydroxide, inner salt)". Organic Syntheses . 48: 12. doi:10.15227/orgsyn.048.0012 ; Collected Volumes, vol. 5, p. 54.
  14. ↑ Campbell, C.D.; Rees, C.W. (1969). "Reactive intermediates. Part I. Synthesis and oxidation of 1- and 2-aminobenzotriazole". J. Chem. Soc. C . 1969 (5): 742–747. doi:10.1039/J39690000742.
  15. ↑ Wilcox Jr., Charles F.; Uetrecht, J. P.; Grohman, K. K. (1972). "Cycloocta[def]biphenylene". J. Am. Chem. Soc. 94 (7): 2532. doi:10.1021/ja00762a068.
  16. ↑ Wilcox Jr., Charles F.; Farley, Erik N. (1983). "Dicycloocta[1,2,3,4-def:1',2',3',4'-jkl]biphenylene. Benzenoid Atropism in a Highly Antiaromatic Polycycle". J. Am. Chem. Soc. 105 (24): 7191–7192. doi:10.1021/ja00362a040.
  17. ↑ Wilcox Jr., Charles F.; Farley, Erik N. (1984). "Dicyclooctabiphenylene. Synthesis and Properties". J. Am. Chem. Soc. 106 (23): 7195–7200. doi:10.1021/ja00335a055.
  18. ↑ Wilcox Jr., Charles F.; Farley, Erik N. (1985). "Cyclooctannelated Biphenylenes. Diagnosis of an Anomalous Bond Length by Analysis of Ring Current Geometric Factors". J. Org. Chem. 50 (3): 351–356. doi:10.1021/jo00203a013.
  19. ↑ Farley, Erik Neil (1984). Dicyclooctabiphenylenes (Thesis). Cornell University.
  20. ↑ Balaban, A. T. (1968). Revue Roumaine de Chimie. 13: 231.{{cite journal}}: Missing or empty |title= (help)
  21. ↑ G. Brunetto, P. A. S. Autreto, L. D. Machado, B. I. Santos, R. P. B. dos Santos, and D. S. Galvao (2012). "Nonzero gap two-dimensional carbon allotrope from porous graphene". J. Phys. Chem. C . 116 (23): 12810–12813. arXiv: 1205.6838 . Bibcode:2012arXiv1205.6838B. doi:10.1021/jp211300n. S2CID   103548116.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  22. ↑ Lüder J., Puglia C., Ottosson H., Eriksson O., Sanyal B., Brena B. (2016). "Many-body effects and excitonic features in 2D biphenylene carbon". J. Chem. Phys. . 144 (2): 024702. Bibcode:2016JChPh.144b4702L. doi:10.1063/1.4939273. PMID   26772582.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  23. ↑ Zhu L., Jin Y.,Xue Q., Li X., Zheng H., Wu T. Ling C. (2016). "Theoretical study of a tunable and strain-controlled nanoporous graphenylene membrane for multifunctional gas separation". J. Mater. Chem. A . 4 (39): 15015–15021. doi:10.1039/C6TA04456E.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  24. ↑ Fan, Qitang; Yan, Linghao; Tripp, Matthias W.; Krejčí, Ondřej; Dimosthenous, Stavrina; Kachel, Stefan R.; Chen, Mengyi; Foster, Adam S.; Koert, Ulrich; Liljeroth, Peter; Gottfried, J. Michael (2021-05-21). "Biphenylene network: A nonbenzenoid carbon allotrope". Science. 372 (6544): 852–856. Bibcode:2021Sci...372..852F. doi:10.1126/science.abg4509. ISSN   0036-8075. PMID   34016779. S2CID   234794559.
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