Chemistry:Diphenylacetylene

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Diphenylacetylene
DiphenylacetyleneSVG.svg
Diphenylacetylene-3D-balls.png
Diphenylacetylene-3D-vdW.png
Names
Preferred IUPAC name
1,1′-Ethynediyldibenzene
Other names
Tolane
1,2-Diphenylethyne
Diphenylethyne
2-Phenylethynylbenzene
Tolan
Identifiers
3D model (JSmol)
606478
ChEBI
ChEMBL
ChemSpider
EC Number
  • 207-926-6
UNII
Properties
C14H10
Molar mass 178.234 g·mol−1
Appearance Colorless solid
Density 1.136 g cm−3[1]
Melting point 62.5 °C (144.5 °F; 335.6 K)
Boiling point 170 °C (338 °F; 443 K) at 19 mmHg
Insoluble
Structure
0 D
Hazards
Safety data sheet Fisher Scientific MSDS
Related compounds
Related compounds
But-2-yne
Dimethyl acetylenedicarboxylate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Diphenylacetylene is the chemical compound C6H5C≡CC6H5. The molecule consists of two phenyl groups attached to a C2 unit. A colorless solid, it is used as a building block in organic synthesis and as a ligand in organometallic chemistry.

Preparation and structure

In one preparation for this compound, benzil is condensed with hydrazine to give the bis(hydrazone), which is oxidized with mercury(II) oxide.[2] Alternatively stilbene is brominated, and the resulting dibromodiphenylethane is subjected to dehydrohalogenation.[3] Yet another method involves the coupling of iodobenzene and the copper salt of phenylacetylene in the Castro-Stephens coupling. The related Sonogashira coupling involves the coupling of iodobenzene and phenylacetylene.

Diphenylacetylene is a planar molecule. The central C≡C distance is 119.8 picometers.[1]

Derivatives

Reaction of diphenylacetylene with tetraphenylcyclopentadienone results in the formation of hexaphenylbenzene in a Diels–Alder reaction.[4]

File:Hexaphenylbenzene synthesis from tetracyclone.tif

Dicobalt octacarbonyl catalyzes alkyne trimerisation of diphenylacetylene to form hexaphenylbenzene.[5]

Diphenylacetylene cyclotrimerization using dicobalt octacarbonyl

Reaction of Ph2C2 with benzal chloride in the presence of potassium t-butoxide affords 3-tert-butoxy-1,2,3-triphenylcyclopropene, which converts to 1,2,3-triphenylcyclopropenium bromide after the elimination of tert-butoxide.[6]

References

  1. 1.0 1.1 Mavridis, A.; Moustakali-Mavridis, I. (1977). "A Reinvestigation of Tolane". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry 33 (11): 3612–3615. doi:10.1107/S0567740877011674. 
  2. Cope, A. C.; Smith, D. S.; Cotter, R. J. (1954). "Diphenylacetylene". Organic Syntheses 34: 42. doi:10.15227/orgsyn.034.0042. 
  3. Lee Irvin Smith; M. M. Falkof (1942). "Diphenylacetylene". Organic Syntheses 22: 50. doi:10.15227/orgsyn.022.0050. 
  4. Fieser, L. F. (1966). "Hexaphenylbenzene". Organic Syntheses 46: 44. doi:10.15227/orgsyn.046.0044. 
  5. Vij, V.; Bhalla, V.; Kumar, M. (8 August 2016). "Hexaarylbenzene: Evolution of Properties and Applications of Multitalented Scaffold". Chemical Reviews 116 (16): 9565–9627. doi:10.1021/acs.chemrev.6b00144. 
  6. Xu, Ruo; Breslow, Ronald (1997). "1,2,3-Triphenylcyclopropenium Bromide". Organic Syntheses 74: 72. doi:10.15227/orgsyn.074.0072.