quinacridone

The name indicates that the compounds are a fusion of acridone and quinoline, although they are not made that way. Classically the parent is prepared from the 2,5-dianilide of terephthalic acid (C₆H₂(NHPh)₂(CO₂H)₂). Condensation of succinosuccinate esters with aniline followed by cyclization affords dihydroquinacridone, which are readily dehydrogenated. The latter is oxidized to quinacridone. Derivatives of quinacridone can be readily obtained by employing substituted anilines. Linear cis-Quinacridones can be prepared from isophthalic acid.{{cite journal|doi=10.1021/cr60245a001|title=Quinacridones|journal=Chemical Reviews|volume=67|pages=1–18|year=1967|last1=Labana|first1=S. S.|last2=Labana|first2=L. L.}}{{cite journal|doi=10.1016/S0143-7208(01)00085-7|title=On quinacridones and their supramolecular mesomerism within the crystal lattice|journal=Dyes and Pigments|volume=52|issue=3|pages=169–181|year=2002|last1=Lincke|first1=Gerhard}}

Quinacridone-based pigments are used to make high performance paints. Quinacridones were first sold as pigments by Du Pont in 1958.{{cite journal |last1=Lomax |first1=Suzanne Quillen |title=Phthalocyanine and quinacridone pigments: their history, properties and use |journal=Studies in Conservation |date=13 December 2013 |volume=50 |issue=sup1 |pages=19–29 |doi=10.1179/sic.2005.50.Supplement-1.19|s2cid=97211023 }} Quinacridones are considered "high performance" pigments because they have exceptional color and weather fastness. Major uses for quinacridones include automobile and industrial coatings. 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.{{cite journal|author1=E.F. Paulus |author2=F.J.J. Leusen |author3=M.U. Schmidt |name-list-style=amp |journal=CrystEngComm|year=2007|volume=9|pages=131|doi=10.1039/b613059c|title=Crystal structures of quinacridones|issue=2|citeseerx=10.1.1.589.5547}}

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"{{cite web |last1=MacEvoy |first1=Bruce |title=handprint : watercolor brands |url=https://www.handprint.com/HP/WCL/pigmt2.html |website=www.handprint.com |access-date=4 October 2019}} and "Acra Violet".{{cite web |last1=Myers |first1=David |title=The Color of Art Pigment Database: Pigment Violet - PV |url=http://www.artiscreation.com/violet.html#.XZeDcudKgac |website=Art is Creation |access-date=4 October 2019}}

Quinacridone derivatives exhibit intense fluorescence in the dispersed state, and high carrier mobility. These properties complement good photo-, thermal, and electrochemical stability. These properties are desired for optoelectronic applications including organic light-emitting diodes (OLEDs), organic solar cells (OSCs), and organic field-effect transistors (OFETs). Due to interplay of intermolecular H-bonding and pi-pi stacking, quinacridone can form a self-assembling, supramolecular organic semiconductor.

:Image:Selfassembly Organic Semiconductor Trixler LMU.jpg, self-assembled quinacridone chains on a graphite background.]]{{clear left}}

{{reflist}}

• {{cite journal | doi = 10.1039/C6TC03621J | title = Quinacridone-based π-conjugated electronic materials | year = 2016 | last1 = Chenguang | first1 = Wang | last2 = Zuolun | first2 = Zhang | last3 = Yue | first3 = Wang |journal = J. Mater. Chem. C | volume = 4 | issue = 42 | pages = 9918–36 }}
• {{cite journal | doi = 10.1002/adma.201204039 | title = Hydrogen-Bonded Semiconducting Pigments for Air-Stable Field-Effect Transistors | year = 2013 | last1 = Głowacki | first1 = Eric Daniel | last2 = Irimia-Vladu | first2 = Mihai | last3 = Kaltenbrunner | first3 = Martin | last4 = Gsiorowski | first4 = Jacek | last5 = White | first5 = Matthew S. | last6 = Monkowius | first6 = Uwe | last7 = Romanazzi | first7 = Giuseppe | last8 = Suranna | first8 = Gian Paolo | last9 = Mastrorilli | first9 = Piero | last10 = Sekitani | first10 = Tsuyoshi | last11 = Bauer | first11 = Siegfried | last12 = Someya | first12 = Takao | last13 = Torsi | first13 = Luisa |author-link13=Luisa Torsi| last14 = Sarıçiftçi | first14 = Niyazi Serdar |author-link14=Niyazi Serdar Sarıçiftçi | journal = Advanced Materials | volume = 25 | issue = 11 | pages = 1563–9 | pmid = 23239229| bibcode = 2013AdM....25.1563G | s2cid = 205247943 }}

Category:Organic semiconductors

Category:Organic pigments

Category:Diketones

Category:Heterocyclic compounds with 5 rings

Category:Nitrogen heterocycles

Category:Acridines