Rubrene

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Rubrene
Skeletal formula
Space-filling model
Rubrene.jpg
Identifiers
CAS number 517-51-1 YesY
PubChem 68203
ChemSpider 61510 YesY
EC number 208-242-0
Jmol-3D images Image 1
Properties
Molecular formula C42H28
Molar mass 532.7 g/mol
Melting point 315 °C (599 °F; 588 K)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Rubrene (5,6,11,12-tetraphenyltetracene) is a red colored polycyclic aromatic hydrocarbon. Rubrene is used as a sensitiser in chemoluminescence and as a yellow light source in lightsticks.

Electronic properties[edit]

As an organic semiconductor, the major application of rubrene is in organic light-emitting diodes (OLEDs) and organic field-effect transistors, which are the core elements of flexible displays. Single-crystal transistors can be prepared using crystalline rubrene, which is grown in a modified zone furnace on a temperature gradient. This technique, known as physical vapor transport, was introduced in 1998.[1][2]

Rubrene holds the distinction of being the organic semiconductor with the highest carrier mobility, reaching 40 cm2/(V·s) for holes. This value was measured in OFETs prepared by peeling a thin layer of single-crystalline rubrene and transferring to a Si/SiO2 substrate.[3]

Crystal structure[edit]

Several polymorphs of rubrene are known. Crystals grown from vapor in vacuum can be monoclinic,[4] triclinic,[5] and orthorhombic motifs.[6] Orthorhombic crystals (space group Bbam) are obtained in a closed system in a two-zone furnace at ambient pressure.[7]

Synthesis[edit]

Rubrene is prepared by treating 1,1,3-triphenylprop-2-yne-1-ol with thionyl chloride.[8]

3-chloro-1,1,3-triphenylpropa-1,2-diene.png

The resulting chloroallene undergoes dimerization and dehydrochlorination to give rubrene.[9]

Rubrene synthesis.png

Redox properties[edit]

Rubrene, like other polycyclic aromatic molecules, undergoes redox reactions in solution. It oxidizes and reduces reversibly at 0.95 V and -1.37 V, respectively vs SCE. When the cation and anion are co-generated in an electrochemical cell, they can combine with annihilation of their charges, but producing an excited rubrene molecule that emits at 540 nm. This phenomenon is called electrochemiluminescence.[10]

References[edit]

  1. ^ A. Laudise, C. Kloc, P. Simpkins, and T. Siegrist "Physical vapor growth of organic semiconductors" J. Cryst. Growth, 1998, vol. 187, pp. 449. doi:10.1016/S0022-0248(98)00034-7
  2. ^ Oana Diana Jurchescu "Molecular organic semiconductors for electronic devices" chapter Low Temperature Crystal Structure of Rubrene Single Crystals Grown by Vapor Transport, PhD thesis (2006) Rijksuniversiteit Groningen.
  3. ^ Tatsuo Hasegawa and Jun Takeya (2009). "Organic field-effect transistors using single crystals". Sci. Technol. Adv. Mater. (free download review) 10 (2): 024314. Bibcode:2009STAdM..10b4314H. doi:10.1088/1468-6996/10/2/024314. 
  4. ^ Taylor, W. H. (1936). Z. Kristallogr. 93: 151. 
  5. ^ S. A. Akopyan, R. L. Avoyan, and Yu. T. Struchkov, Z. Strukt. Khim. 3, 602 (1962)
  6. ^ Henn, D. E. and Williams, W. G. (1971). "Crystallographic data for an orthorhombic form of rubrene". J. Appl. Cryst. 4 (3): 256. doi:10.1107/S0021889871006812. 
  7. ^ I. Bulgarovskaya, V. Vozzhennikov, S. Aleksandrov, and V. Belsky, Latv. PSR Zinat. Akad. Vestis, Fiz. Teh. Zinat. Ser. 4, 53 (1983) 115.
  8. ^ Furniss, B. Vogel's Textbook of Practical Organic Chemistry (5th ed.). pp. 840–841. 
  9. ^ Furniss, B. Vogel's Textbook of Practical Organic Chemistry (5th ed.). pp. 844–845. 
  10. ^ Richter, M. M., "Electrochemiluminescence (ECL)", Chemical Reviews 2004, 104, 3003. doi:10.1021/cr020373d