Pentacene

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Structural formula
Structural formula of pentacene
General
Surname Pentacene
Molecular formula C 22 H 14
Brief description

black solid

External identifiers / databases
CAS number 135-48-8
EC number 205-193-7
ECHA InfoCard 100,004,722
PubChem 8671
Wikidata Q424450
properties
Molar mass 278.35 g mol −1
Physical state

firmly

density

1.35 g cm −3

Melting point

271 ° C

solubility

almost insoluble in water, sparingly soluble in organic solvents

safety instructions
GHS labeling of hazardous substances
no GHS pictograms
H and P phrases H: no H-phrases
P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Pentacene (C 22 H 14 ) is a polycyclic aromatic hydrocarbon with five linearly fused benzene rings .

properties

Deep blue pentacene crystals
Pentacenes on Ni (111) surface

In its pure form, pentacene forms deep blue crystals which, however, are very sensitive to oxidation. With increasing contamination, pentacene turns purple. Decomposition is observed from 300 ° C. in the presence of air. Similar to the two next higher homologues hexacene and heptacene , pentacene is only sparingly soluble in organic solvents and readily enters into Diels-Alder reactions. The compound crystallizes in the triclinic crystal system. According to August, the vapor pressure function results according to lg (P) = −A / T + B (P in Torr, T in K) with A = 18867 and B = 35.823 in the temperature range from 171 ° C to 212 ° C. The solubilities are at 20 ° C in chloroform 0.21 g l −1 , in tetrahydrofuran 0.11 g l −1 , in N , N -dimethylformamide 0.1 g l −1 and toluene 0.18 g l −1 .

application

Pentacene is used as a semiconductor in organic electronics . a. used for organic thin film field effect transistors (OFET). For these purposes it is either thermally evaporated or applied by solution processing, e.g. For example, by spin coating ( spin coating ). Since pentacene is almost insoluble in all common solvents, pentacene derivatives are used, which have increased solubility. Two approaches are known: either soluble Diels-Alder adducts ( Diels-Alder reaction ) of pentacene are processed (non-semiconducting), which are thermally treated after application and, with retro-Diels-Alder cleavage, those for the function as semiconductors restore necessary pentacene structure, or soluble pentacene derivatives are processed in which the pentacene structure is still preserved and therefore no subsequent thermal activation is necessary.

Syntheses

Exemplary access routes to (substituted) pentacene. Substituents on the starting materials are omitted for better clarity.

Typical synthesis strategies for pentacenes proceed via pentacene-6,13-diones or pentacene-5,14-diones. The diagram opposite summarizes some of the routes over the 6,13-Dione. By using suitably substituted starting materials - not shown in the scheme for improved clarity - numerous multiply and asymmetrically substituted pentacenes are accessible. The synthesis of pentacene-6,13-dione was described by Ried and Anthöfer as early as 1953. Condensation of dialdehydes with hydroquinones was used by Nuckolls et al. a. to study self-organization phenomena in the production of organic field effect transistors. The reaction of quinodimethanes with dienophiles, initially described by Cava, was u. a. by Anthony u. a. added to make a number of multiply substituted, readily soluble pentacene derivatives accessible. Solubility was achieved by adding tri-isoproplysilyl-acetylene groups to the pentacenedione with subsequent reduction to pentacene with SnCl 2 / HCl.

Individual evidence

  1. ↑ a b data sheet pentacene from Acros, accessed on December 19, 2019.
  2. ^ A b Theo Siegrist et al.: Enhanced Physical Properties in a Pentacene Polymorph . In: Angewandte Chemie International Edition . tape 40 , no. 9 , May 3, 2001, pp. 1732-1736 , doi : 10.1002 / 1521-3773 (20010504) 40: 9 <1732 :: AID-ANIE17320> 3.0.CO; 2-7 .
  3. ↑ a b c d Entry on pentacene. In: Römpp Online . Georg Thieme Verlag, accessed on July 16, 2011.
  4. ↑ a b Datasheet Pentacene, 99% from Sigma-Aldrich , accessed on December 1, 2019 ( PDF ).
  5. ^ Vahur Oja, Eric M. Suuberg: Vapor Pressures and Enthalpies of Sublimation of Polycyclic Aromatic Hydrocarbons and Their Derivatives . In: J. Chem. Eng. Data . tape 43 , no. 3 , 1998, p. 486-492 , doi : 10.1021 / je970222l .
  6. ↑ Zhong Huang, Yuansheng Jang, Xiuying Yang, Weiliang Cao, Jingchang Zhang: The synthesis and photoelectric study of 6,13-bis (4-propylphenyl) pentacene, and its TiO 2 nano-sized composite films . In: Journal of Physics and Chemistry of Solids . tape 71 , no. 3 , 2010, p. 296-302 , doi : 10.1016 / j.jpcs.2009.12.080 .
  7. ↑ a b c Hagen Klauk (Ed.): Organic Electronics: Materials, Manufacturing and Applications . Wiley-VCH Verlag, Weinheim 2006, ISBN 3-527-31264-1 .
  8. ↑ John E. Anthony: Functionalized Acenes and Heteroacenes for Organic Electronics . In: Chemical Reviews . tape 106 , no. 12 , 2006, p. 5028-5048 , doi : 10.1021 / cr050966z .
  9. ^ John E. Anthony: The Larger Acenes: Versatile Organic Semiconductors . In: Angewandte Chemie International Edition . tape 47 , no. 3 , January 4, 2008, p. 452-483 , doi : 10.1002 / anie.200604045 .
  10. ^ S. Allard, M. Forster, B. Souharce, H. Thiem, U. Scherf: Organic Semiconductors for Solution-Processable Field-Effect Transistors (OFETs) . In: Angew. Chem. Int. Ed. , 2008, 47 , 4070-4098.
  11. ↑ WO 2005/055248 A2: Improvements in and relating to Organic Semiconducting Layers . WIPO download ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / patentscope.wipo.int
  12. ↑ W. Ried, F. Anthöfer: Simple synthesis for pentacene-6,13-quinone. In: Angew. Chem. Vol. 65, 1953, p. 601.
  13. ↑ Q. Miao, M. Lefenfeld, T.-Q. Nguyen, T. Siegrist, C. Kloc, C. Nuckolls: Self-Assembly and Electronics of Dipolar Linear Acenes. In: Adv. Mater. Volume 17, No. 4, 2005, pp. 407-412, doi: 10.1002 / adma.200401251 (details of the chemical synthesis are described in the Supporting Informations.).
  14. ↑ MP Cava, RL Shirley: Condensed Cyclobutane Aromatic Compounds. X. Naphtho [b] cyclobutene. In: J. Am. Chem. Soc. Volume 82, No. 3, 1960, pp. 654-656, doi: 10.1021 / ja01488a039 .
  15. ^ CR Schwarz, SR Parkin, JE Bullock, JE Anthony, AC Mayer, GG Malliaras: Synthesis and Characterization of Electron-Deficient Pentacenes. In: Organic Letters. Volume 7, No. 15, 2005, pp. 3163-3166, doi: 10.1021 / ol050872b .

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