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{{chembox |
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{{Chembox |
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| verifiedrevid = 402700876 |
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| ImageFile = Triphenylmethane.png |
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| verifiedrevid = 432156972 |
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| ImageSize = |
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| ImageFile = Triphenylmethan.svg |
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| IUPACName = Triphenylmethane |
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| ImageSize = 180px |
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| OtherNames = 1,1',1"-Methylidynetrisbenzene |
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| ImageFile1 = Triphenylmethane-3D-balls.png |
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| Section1 = {{Chembox Identifiers |
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| ImageSize1 = 180px |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| PIN = 1,1{{prime}},1{{pprime}}-Methanetriyltribenzene |
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| OtherNames = Triphenylmethane<br />1,1{{prime}},1{{pprime}}-Methylidynetrisbenzene |
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|Section1={{Chembox Identifiers |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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| CASNo = 519-73-3 |
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| ChEBI_Ref = {{ebicite|correct|EBI}} |
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| ChEBI = 76212 |
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| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
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| ChemSpiderID = 10169 |
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| ChemSpiderID = 10169 |
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| EINECS = 208-275-0 |
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| PubChem = 10614 |
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| UNII_Ref = {{fdacite|correct|FDA}} |
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| UNII = 8O4UTW9E17 |
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| InChI = 1/C19H16/c1-4-10-16(11-5-1)19(17-12-6-2-7-13-17)18-14-8-3-9-15-18/h1-15,19H |
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| InChI = 1/C19H16/c1-4-10-16(11-5-1)19(17-12-6-2-7-13-17)18-14-8-3-9-15-18/h1-15,19H |
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| InChIKey = AAAQKTZKLRYKHR-UHFFFAOYAF |
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| InChIKey = AAAQKTZKLRYKHR-UHFFFAOYAF |
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} |
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| StdInChIKey = AAAQKTZKLRYKHR-UHFFFAOYSA-N |
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| StdInChIKey = AAAQKTZKLRYKHR-UHFFFAOYSA-N |
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| SMILES = c1c(cccc1)C(c2ccccc2)c3ccccc3 |
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| CASNo_Ref = {{cascite|correct|CAS}} |
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}} |
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| CASNo = 519-73-3 |
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|Section2={{Chembox Properties |
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| EINECS = 208-275-0 |
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| C=19|H=16 |
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| PubChem = 10614 |
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| Density = 1.014{{nbsp}}g/cm<sup>3</sup> |
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| SMILES = c1c(cccc1)C(c2ccccc2)c3ccccc3 |
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| MeltingPtC = 92 to 94 |
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| MeltingPt_notes = |
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| BoilingPtC = 359 |
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| Solubility = Insoluble |
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| SolubleOther = Soluble in ]<ref>{{cite web |url=https://www.chemicalbook.com/ChemicalProductProperty_EN_CB5689132.htm |title=Triphenylmethane {{pipe}} 519-73-3}}</ref> and hexane |
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| pKa = 33.3 |
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| Appearance = Colorless solid |
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| MagSus = −165.6×10<sup>−6</sup>{{nbsp}}cm<sup>3</sup>/mol |
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|Section3={{Chembox Hazards |
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| Hazards_ref= |
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| GHSPictograms = {{GHS07}} |
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| GHSSignalWord = Warning |
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| HPhrases = {{H-phrases|315|319|335}} |
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| PPhrases = {{P-phrases|}} |
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| ExternalSDS = | MainHazards = |
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| FlashPt = |
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| AutoignitionPt = |
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| Section2 = {{Chembox Properties |
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| Formula = C<sub>19</sub>H<sub>16</sub> |
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| MolarMass = 244.33 g/mol |
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| Appearance = |
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| Density = 1.014 g/cm<sup>3</sup> |
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| MeltingPt = 92-94 °C |
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| BoilingPt = 359 °C |
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| Solubility = insoluble |
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}} |
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| Section3 = {{Chembox Hazards |
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| RPhrases = {{R36}} {{R37}} {{R38}} |
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| ExternalMSDS = | MainHazards = |
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| FlashPt = |
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'''Triphenylmethane''', or '''triphenyl methane''', is the ] with the ] (C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>CH. This colorless solid is soluble in nonpolar organic solvents and not in water. Triphenylmethane has the basic skeleton of many synthetic ]s called ]s, many of them are ]s, and some display ]. A '''trityl''' group in organic chemistry is a triphenylmethyl group Ph<sub>3</sub>C, e.g. ] — trityl chloride. |
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'''Triphenylmethane''' or '''triphenyl methane''' (sometimes also known as '''Tritan'''), is the ] with the ] (C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>CH. This colorless solid is soluble in nonpolar organic solvents and not in water. Triphenylmethane is the basic skeleton of many synthetic ]s called ]s, many of them are ]s, and some display ]. A '''trityl''' group in organic chemistry is a triphenylmethyl group Ph<sub>3</sub>C, e.g. ] (trityl chloride) and the ] (trityl radical). |
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==Preparation== |
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==Preparation== |
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Triphenylmethane can be synthesized by ] from ] and ] with ] ]: |
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Triphenylmethane was first synthesized in 1872 by the German chemist ] and his Dutch student Antoine Paul Nicolas Franchimont (1844–1919) by heating ] (Hg(C<sub>6</sub>H<sub>5</sub>)<sub>2</sub>, ''Quecksilberdiphenyl'') with ] (C<sub>6</sub>H<sub>5</sub>CHCl<sub>2</sub>, ''Benzylenchlorid'').<ref>Aug. Kekulé and A. Franchimont (1872) (On triphenylmethane), ''Berichte der deutschen chemischen Gesellschaft'', '''5''' : 906–908.</ref> |
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: 3 C<sub>6</sub>H<sub>6</sub> + CHCl<sub>3</sub> → Ph<sub>3</sub>CH + 3 HCl |
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Triphenylmethane can be synthesized by ] from ] and ] with ] ]: |
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Alternatively, benzene may react with ] using the same catalyst to obtain the ]-] adduct, which is hydrolyzed with dilute acid:<ref>{{OrgSynth | title = Triphenylmethane | author = J. F. Norris | year=1941| collvol = 1 | collvolpages = 548 | prep = cv1p0548}}</ref> |
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:3 C<sub>6</sub>H<sub>6</sub> + CHCl<sub>3</sub> → Ph<sub>3</sub>CH + 3 HCl |
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Alternatively, benzene may react with ] using the same catalyst to obtain the ]–] adduct which is then treated with diethyl ether for 24 hours at room temperature and hydrolyzed with concentrated hydrochloric acid:<ref>{{cite journal |title= Triphenylmethane |author= J. F. Norris |journal= Organic Syntheses |year= 1925 |volume= 4 |page= 81 |doi= 10.15227/orgsyn.004.0081}}</ref> |
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:3 C<sub>6</sub>H<sub>6</sub> + CCl<sub>4</sub> + AlCl<sub>3</sub> → Ph<sub>3</sub>CCl·AlCl<sub>3</sub> |
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:Ph<sub>3</sub>CCl·AlCl<sub>3</sub> + Et<sub>2</sub>O + HCl → Ph<sub>3</sub>CH |
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It can also be synthesized from ], which is prepared from ] and ]. |
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: 3 C<sub>6</sub>H<sub>6</sub> + CCl<sub>4</sub> + AlCl<sub>3</sub> → Ph<sub>3</sub>CCl·AlCl<sub>3</sub> |
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:Ph<sub>3</sub>CCl·AlCl<sub>3</sub> + HCl → Ph<sub>3</sub>CH |
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==Reactions of C-H bond== |
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Synthesis from ], prepared from ] and ], is used as well. |
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The Ph<sub>3</sub>C-H bond is relatively weak, with a ] (BDE) of 81 kcal/mol, or about 24 kcal/mol less than methane.<ref>{{cite journal |doi=10.1021/acs.chemrev.6b00664|title=The Essential Role of Bond Energetics in C–H Activation/Functionalization|year=2017|last1=Xue|first1=Xiao-Song|last2=Ji|first2=Pengju|last3=Zhou|first3=Biying|last4=Cheng|first4=Jin-Pei|journal=Chemical Reviews|volume=117|issue=13|pages=8622–8648|pmid=28281752}}</ref> Correspondingly, triphenylmethane is mildly acidic, with a ] of 33.297.<ref>{{cite journal|author=Ronald Breslow and William Chu|journal=Journal of the American Chemical Society|year=1969|doi=10.1021/ja00710a077|title=Electrochemical determinations of p''K''<sub>a</sub>'s. Triphenylmethanes and cycloheptatriene|volume=92|issue=7|pages=2165}}</ref> |
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Triphenylmethane is significantly more acidic than most other hydrocarbons because the charge is ] over three phenyl rings. Steric effects however prevent all three phenyl rings from achieving coplanarity simultaneously. Consequently ] is even more acidic, albeit only slightly, because in its anion the charge is spread over two phenyl rings at the same time. |
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==Acidity== |
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The ] of the hydrogen on the central carbon is around 31. Triphenylmethane is significantly more acidic than most other hydrocarbons because the planar trityl anion is stabilized by extensive ] over three phenyl rings. However, delocalization does not occur simultaneously over all phenyl rings, due to sterics: each phenyl ring forces the other two out of coplanarity to form a three-vaned fan, such that delocalization only occurs if the sp<sup>2</sup> orbital of the anionic carbon is properly aligned with one of the aromatic systems. The trityl anion absorbs strongly in the visible region, making it red. This colour can be used as an indicator when maintaining anhydrous conditions with ]; the hydride reagent reacts with water to form solid calcium hydroxide, while it is also a strong enough base to generate the trityl anion. If the hydride is used up then the solution will turn colourless. The sodium salt can be prepared also from ]:<ref>{{OrgSynth | author = W. B. Renfrow Jr and C. R. Hauser | title = Triphenylmethylsodium | collvol = 2 | collvolpages = 607| year = 1943 | prep = CV2P0607}}</ref> |
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The trityl anion is isolable in ]s: |
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:(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>CCl + 2 Na → (C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>CNa + NaCl |
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:] |
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Before the popularization of ] and related strong bases, trityl sodium was often used as a strong, non-nucleophilic base. |
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Its sodium salt can be prepared from ]:<ref>{{OrgSynth | author = W. B. Renfrow Jr and C. R. Hauser | title = Triphenylmethylsodium | collvol = 2 | collvolpages = 607| year = 1943 | prep = CV2P0607}}</ref> |
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:(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>CCl + 2 Na → (C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>CNa + NaCl |
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The use of tritylsodium as a strong, ] has been eclipsed by the popularization of ] and related strong bases. |
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The unmodified anion is red, and can be used as an indicator in ]s. Derived substances have proven useful as chemical dyes. |
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==Triarylmethane dyes== |
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==Triarylmethane dyes== |
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{{Main|Triarylmethane dye}} |
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{{Main|Triarylmethane dye}} |
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Examples of triarylmethane dyes are ]: |
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Examples of triarylmethane dyes are ]: |
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or ]: |
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And the ]-bearing ]: |
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==Trityl group== |
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:] |
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===Protecting group=== |
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The triphenylmethyl substituent, also called trityl after 1927 suggestion by ] et al.<ref>{{Cite journal |last=Helferich |first=B. |last2=Bredereck |first2=H. |last3=Schneidmüller |first3=A. |date=1927 |title=Acylwanderung an partiell acylierten Methyl‐glucosiden |url=https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/jlac.19274580108 |journal=Justus Liebigs Annalen der Chemie |language=de |volume=458 |issue=1 |pages=111–116 |doi=10.1002/jlac.19274580108 |issn=0075-4617}}</ref>, is widely used in organic chemistry. Trityl serves as a ] for alcohols.<ref>{{cite journal |doi=10.15227/orgsyn.022.0056|title=β-''d''-Glucose-1,2,3,4-Tetraacetate|journal=Organic Syntheses|year=1942|volume=22|page=56|author=Delbert D. Reynolds, William Lloyd Evans |
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}}</ref> |
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: protection (requires proton acceptor): Ph<sub>3</sub>CCl + ROH → Ph<sub>3</sub>COR + HCl |
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: deprotection: Ph<sub>3</sub>COR + HBr → ROH + Ph<sub>3</sub>CBr |
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===Platform for unusual functional groups=== |
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Trityl derivatives of reactive functional groups are often crystalline and in some cases sterically stabilized relative to less bulky derivatives. Three such derivatives are ] (Ph<sub>3</sub>CSNO), tritylsulfenyl chloride (Ph<sub>3</sub>CSCl), and trityl sulfenamide (Ph<sub>3</sub>CSNH<sub>2</sub>).<ref>{{cite journal |doi=10.1107/S0108270194004439|title=Molecules isoelectronic with 2,2,2-triphenylethanol: Multiple Hydrogen-Bonding Modes in the Structures of O-Tritylhydroxylamine, Ph<sub>3</sub>CONH<sub>2</sub>, and Triphenylmethanesulfenamide, Ph<sub>3</sub>CSNH<sub>2</sub>|year=1994|last1=Glidewell|first1=C.|last2=Ferguson|first2=G.|journal=Acta Crystallographica Section C Crystal Structure Communications|volume=50|issue=8|pages=1362–1366|bibcode=1994AcCrC..50.1362G }}</ref> |
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==See also== |
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==References== |
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==References== |
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