Quinacridone

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Quinacridone
Chinacridon.svg
Identifiers
CAS number 1047-16-1 YesY
PubChem 13976
ChemSpider 13369 YesY
UNII 11P487375P YesY
Jmol-3D images Image 1
Properties
Molecular formula C20H12N2O2
Molar mass 312.32 g mol−1
Appearance Red powder (nanoparticles)
Density 1.47 g/cm³
Solubility in water Insoluble
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Quinacridone is an organic molecule utilized in the formation of organic pigments. It is an organic compound with the molecular formula C20H12N2O2. Numerous derivatives of quinacridone constitute the Quinacridone pigment family, which finds extensive use in industrial colorant applications such as robust outdoor paints and inkjet toners.[1]

Synthesis[edit]

Condensation of succinosuccinate ester with aniline followed by cyclization affords dihydroquinacridone. The latter is oxidized to quinacridone.[1] Derivatives of quinacridone can be readily obtained by employing substituted anilines.

Quinacridones[edit]

Quinacridones are a family of synthetic pigments used to make high performance paints. Quinacridones are considered "high performance" pigments because they have exceptional color and weather fastness. Major uses for quinacridones include automobile coatings as well as other industrial coatings. They can also be used in artist's paints, including oils, acrylics, and watercolors. Nanocrystalline dispersions of quinacridone pigments functionalized with solubilizing surfactants are the most common magenta printing ink.

Typically deep red to violet in color, the hue of quinacridone is affected not only by the R-groups on the molecule but by the crystal form of the solid. For example, the γ crystal modification of unsubstituted quinacridone provides a strong red shade that has excellent color fastness and resistance to solvation. Another important modification is the β phase which provides a maroon shade that is also more weather resistant and light-fast. Both crystal modifications are more thermodynamically stable than the α crystal phase. The γ crystal modification is characterized by a criss-cross lattice where each quinacridone molecule hydrogen-bonds to four neighbors via single H-bonds. The β phase, meanwhile, consists of linear chains of molecules with double H-bonds between each quinacridone molecule and two neighbors.[2]

Basic modifications to the chemical structure of quinacridones include the addition of CH3 and Cl substituents. Some magenta shades of quinacridone are labeled under the proprietary name "Thio Violet" and "Acra Violet".

Semiconductor[edit]

Quinacridone can function as an organic semiconductor that is remarkable for air-stable operation.[3] Due to interplay of intermolecular H-bonding and pi-pi stacking, quinacridone can form a self-assembling, supramolecular organic semiconductor. The following image, taken by a scanning tunneling microscope, shows these self-assembled quinacridone chains on a graphite background.

Selfassembly Organic Semiconductor Trixler LMU.jpg

References[edit]

  1. ^ a b K. Hunger. W. Herbst "Pigments, Organic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2012. doi:10.1002/14356007.a20_371
  2. ^ E.F. Paulus, F.J.J. Leusen, and M.U. Schmidt (2007). "Crystal structures of quinacridones". Cryst Eng Comm 9 (2): 131. doi:10.1039/b613059c. 
  3. ^ Głowacki, Eric Daniel; Irimia-Vladu, Mihai; Kaltenbrunner, Martin; Gsiorowski, Jacek; White, Matthew S.; Monkowius, Uwe; Romanazzi, Giuseppe; Suranna, Gian Paolo; Mastrorilli, Piero; Sekitani, Tsuyoshi; Bauer, Siegfried; Someya, Takao; Torsi, Luisa; Sariciftci, Niyazi Serdar (2013). "Hydrogen-Bonded Semiconducting Pigments for Air-Stable Field-Effect Transistors". Advanced Materials 25 (11): 1563–9. doi:10.1002/adma.201204039. PMID 23239229.