{{chembox | Verifiedfields = changed | Watchedfields = changed | verifiedrevid = 477221399 | ImageFile1 = 4-Cyano-4'-pentylbiphenyl.svg | ImageSize1 = 260px | ImageAlt1 = Skeletal formula of 4-cyano-4'-pentylbiphenyl | ImageFile2 = 5CB-from-xtal-3D-bs-17.png | ImageSize2 = 210 | ImageAlt2 = Space-filling model of the 4-cyano-4'-pentylbiphenyl molecule | PIN = 4′-Pentyl[1,1′-biphenyl]-4-carbonitrile | OtherNames = 4'-Amyl-4-biphenylcarbonitrile, 4'-Pentyl-4-biphenylcarbonitrile, 4-Amyl-4'-cyanobiphenyl |Section1={{Chembox Identifiers | SMILES = N#Cc1ccc(cc1)c2ccc(cc2)CCCCC | InChIKey = HHPCNRKYVYWYAU-UHFFFAOYAV | StdInChI_Ref = {{stdinchicite|changed|chemspider}} | StdInChI = 1S/C18H19N/c1-2-3-4-5-15-6-10-17(11-7-15)18-12-8-16(14-19)9-13-18/h6-13H,2-5H2,1H3 | StdInChIKey_Ref = {{stdinchicite|changed|chemspider}} | StdInChIKey = HHPCNRKYVYWYAU-UHFFFAOYSA-N | CASNo = 40817-08-1 | UNII_Ref = {{fdacite|correct|FDA}} | UNII = 2R6RYG3ZGM | PubChem = 92319 | EC_number = 255-093-2 | CASNo_Ref = {{cascite|changed|CAS}} | ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}} | ChemSpiderID = 83347 | InChI = 1/C18H19N/c1-2-3-4-5-15-6-10-17(11-7-15)18-12-8-16(14-19)9-13-18/h6-13H,2-5H2,1H3 }} |Section2={{Chembox Properties | C=18 | H=19 | N=1 | Appearance = Colorless if isotropic or cloudy white if nematic | Density = 1.022 g/cm<sup>3</sup><ref name="Zannoni"/> | MeltingPtC = 22.5<ref name="Zannoni"/> | RefractIndex = n<sub>//</sub> = 1.71, n<sub>⟂</sub> = 1.53<ref name="Zannoni"/> | Viscosity = 28 mPa·s<ref name="Zannoni"/> }} |Section7={{Chembox Hazards | ExternalSDS = [http://www.sigmaaldrich.com/MSDS/MSDS/DisplayMSDSPage.do?country=US&language=en&productNumber=328510&brand=ALDRICH&PageToGoToURL=http%3A%2F%2Fwww.sigmaaldrich.com%2Fcatalog%2Fproduct%2Faldrich%2F328510%3Flang%3Den] | NFPA-H = 2 | NFPA-F = 1 | NFPA-R = 0 | NFPA-S = | GHSPictograms = {{GHS07}} | GHSSignalWord = Warning | HPhrases = {{H-phrases|302|312|315|319|332|335}} | PPhrases = {{P-phrases|261|264|270|271|280|301+312|302+352|304+312|304+340|305+351+338|312|321|322|330|332+313|337+313|362|363|403+233|405|501}} }} }}
'''4-Cyano-4'-pentylbiphenyl''' is a commonly used nematic liquid crystal with the chemical formula C<sub>18</sub>H<sub>19</sub>N. It frequently goes by the common name 5CB. 5CB was first synthesized by George William Gray, Ken Harrison, and J.A. Nash at the University of Hull in 1972 and at the time it was the first member of the cyanobiphenyls.<ref name=gray/><ref name=Collings/> The liquid crystal was discovered after Gray's group received a grant from the UK Ministry of Defence to find a liquid crystal that had liquid crystal phases near room temperature with the specific intention of using them in liquid crystal displays. The molecule is about 20 Å long. The liquid crystal 5CB undergoes a phase transition from a crystalline state to a nematic state at 22.5 °C and it goes from a nematic to an isotropic state at 35.0 °C.<ref name="Zannoni"/>
==Production== 5CB is produced by modifying biphenyl in a linear manner. First Br<sub>2</sub> is added to the biphenyl to introduce a bromine atom to the end of the moiety. Next aluminium chloride and C<sub>4</sub>H<sub>9</sub>COCl is added to the sample, followed by the addition of potassium hydroxide and NH<sub>2</sub>NH<sub>2</sub>. By this point the molecule will have a bromine atom on one end of the rigid core and C<sub>5</sub>H<sub>11</sub> on the other end. Finally, introduction of copper(I) cyanide and DMF results in the removal of the bromine and its replacement with CN, yielding 5CB.<ref name=Collings/>
:File:Synthesis of 5CB..svg
== References == <references>
<ref name=Collings>{{cite book | last1= Collings | first1= Peter J. | editor1-first= George William | editor1-last= Gray | editor1-link= George William Gray | editor2-first= J. W. | editor2-last= Goodby | editor3-first= A. | editor3-last= Fukuda | last2= Hird | first2= Michael | year= 1997 | title= Introduction to Liquid Crystals: Chemistry and Physics | publisher= Taylor and Francis Ltd. | isbn= 0-7484-0643-3 | url-access= registration | url= https://archive.org/details/introductiontoli0000coll|pages=53, 151–152 }}</ref>
<ref name=gray>{{cite journal | last1=Gray | first1=George William | author-link1= George William Gray | last2=Harrison | first2=Ken J. | last3=Nash | first3=J A. | journal=Electronics Letters | volume=9 | number=6 | pages=130–131 | title= New family of nematic liquid crystals for displays | year=1973 | doi=10.1049/el:19730096| bibcode=1973ElL.....9..130G }}</ref>
<ref name="Zannoni">{{cite book | last=Zannoni | first=Claudio | title=Liquid crystals and their computer simulations |publisher=Cambridge University Press| publication-place=Cambridge, United Kingdom | date=2022 | isbn=978-1-108-53963-0 | page=15}}</ref>
</references>
== Further reading == *{{cite journal | last1=Gray | first1=George William | author-link1= George William Gray | journal=Liquid Crystals | volume=24 | issue=1 |date=January 1998 | pages=5–14 | title= Reminiscences from a life with liquid crystals | doi=10.1080/026782998207523 }} *{{cite journal | last1=Seo | first1=D. S. | last2=Matsuda | first2=H. | last3=Oh-Ide | first3=T. | last4=Kobayashi | first4= S. | journal=Molecular Crystals and Liquid Crystals | volume=224 | issue=1 | pages=13–31 | title= ''Alignment of Nematic Liquid Crystal(5CB) on the Treated Substrates: Characterization of Orientation Films, Generation of Pretilt Angles, and Surface Anchoring Strength'' | year=1993 | doi=10.1080/10587259308032475 }} *{{cite journal | last1=Vill | first1=Volkmar | journal=Liquid Crystals | volume=24 | issue=1 |date=January 1998 | pages=21–24 | title= Grey levels in the history of liquid crystals | doi=10.1080/026782998207541 }}
== External links == *[https://web.archive.org/web/20090817143937/http://wwwitp.physik.tu-berlin.de/muschik/liquid_crystals/mol_5cb.html Space Filling Model of 5CB] * {{cite web |url=http://mraths.org.uk/?page_id=576 |title=Liquid Crystal Displays (1973-1982) |publisher=Malvern Radar and Technology History Society |year=2016}}
{{DEFAULTSORT:Cyano-4'-Pentylbiphenyl, 4-}} Category:Liquid crystals Category:Liquid crystal displays Category:Nitriles Category:Pentyl compounds