Triarylmethyl Cations Research Articles

Oxidation reduction reactions involving nitro groups in trifluoromethanesulfonic acid. Part 2. The reactions of chloromethylbenzenes with aromatic nitro Compounds

2-Chloro-1,3-dimethylbenzene reacts with 1,4-dinitrobenzene in trifluoromethanesulfonic acid (99%) at 70 °C to give, after quenching, a 45% yield of tris(4-chloro-3,5-dimethylphenyl)methanol. Some other chloro compounds and a range of aromatic nitro compounds react in a similar manner. From isotopic labelling (13C, 2H), kinetic studies, and substituent effects, the reaction appears to involve a rate-determining hydride transfer from the aromatic chloro compound to the protonated nitro compound followed by a series of benzylations, debenzylations and rebenzylations accompanied by further oxidation reactions and leading finally to the corresponding triarylmethyl cations.

Reactivities of diarylmethyl and triarylmethyl cations with primary amines in aqueous acetonitrile solutions. The importance of amine hydration

By use of the technique of laser flash photolysis, rate constants k(RNH 2 ) have been directly measured for the reactions of primary amines RCH 2 NH 2 (R=CH 3 CH 2 , CH 3 OCH 2 , NCCH 2 , CF 3 ) with diarylmethyl cations (D + ) in acetonitrile/water solutions

Novel oxidation reduction reactions involving nitro groups and methyl groups in trifluoromethanesulfonic acid

2-Chloro-1,3-dimethylbenzene reacts with p-dinitrobenzene in trifluoromethanesulfonic acid at 70 °C to give the corresponding triarylmethyl cation and p-diaminobenzene.

Reactivities of 9-arylfluoren-9-yl and 1-(4-dimethylaminophenyl)ethyl cations in water and trifluoroethanol studied by laser flash photolysis

9-Arylfluoren-9-yl cations have been observed as transient intermediates upon 248 nm laser photolysis of 9-arylfluoren-9-ols in 2,2,2-trifluoroethanol (TFE) and 1:4 (v/v) acetonitrile–water. Quantum yields for the formation of the cations were measured and found to lie in the range 0.5–0.8. Rate constants for the decay of the cations in the two solvents parallel each other, a plot of log kTFEversus log kw being linear with a slope of 1.00. These rate constants are approximately two orders of magnitude larger than those observed in the same solvent for the corresponding monosubstituted triarylmethyl cations. Substituent effects in the two series are similar. For both the hydration reaction and the overall equilibrium, a two-parameter treatment dissecting the substituent contributions into resonance and polar effects shows that the former are more important in the triarylmethyl series, while the latter are more important in the fluorenyl series. Twisting of the 9-aryl ring out of coplanarity with the fluorenyl ring is the likely cause of the diminished resonance interaction in this system. The 1-(4-dimethylaminophenyl)ethyl cation has been observed in TFE and 1:1 TFE–W, being generated by photoprotonation of 4-dimethylaminostyrene. Rate constants for decay are about 50 times smaller than those previously estimated by a clock method. The failure of the latter approach is associated with the rate constant for the clock nucleophile becoming significantly less than diffusion control for this highly stable cation. An extended log kw–pKR correlation is constructed. This shows a series of reasonably parallel lines associated with different families. In considering cations with the same pKR′ the order of inherent reactivity is 9-unsubstituted-9-xanthylium ∼ cyclic dialkoxy-carbocation > phenyltropylium > diarylmethyl ∼9-arylxanthylium > triarylmethyl ∼9-arylfluoren-9-yl. The log kw–pKR data for each family are reasonably satisfied by a linear relationship, with a slope d(log kw)/dpKR of 0.6 ± 0.1. The triarylmethyl and 9-arylfluoren-9-yl cations form a contiguous series covering 26 pKR units. The data for these indicate that there is probably a gentle downward curvature in the correlation, particularly at the high reactivity end. This is consistent with a Hammond effect on the transition state such that it becomes more cation-like in the hydration direction for more reactive cations.

ChemInform Abstract: Directed ortho‐Lithiation of Lithium Thiophenolate. New Methodology for the Preparation of ortho‐Substituted Thiophenols and Related Compounds.

The directed ortho-lithiation of lithium thiophenolate by reaction with n-butyllithium in cyclohexane with N,N,- N',N'-tetramethylethylenediamine gives almost quantitative conversion to lithium 2-lithiobenzenethiolate (1). Reactions of this dilithio derivative with a variety of electrophiles (DzO, carbon dioxide, acetone, diphenyl disulfide, methyl iodide, and thioxanthone) are described. The adduct to thioxanthone is ring-closed to form a triarylmethyl cation (9), and its related carbinol (8), with two o,o'-sulfide bridges.

Structures of the transition states of some intermolecular hydride transfer reactions

The large k H/k D isotope effects, 7–9, obtained in the hydride transfer reactions of triarylmethanes with triarylmethyl cations support linear rather than nonlinear transition states.

Intermolecular cyclization of o-fuchsones

o-Fuchsones formed by dehydrohalogenation of o-hydroxyaryl(diaryl)methyl chlorides with tertiary amines undergo a cyclization to eight-membered dimers of the type head to tail. The dimerization reaction is catalyzed by tertiary amines hydrochlorides involving very likely triarylmethyl cation as intermediates.

Reaction of hydride complexes of platinum and iridium with triarylmethyl cations

1. The hydride complexes of Pt and Ir are hydride-ion donors toward triarylmethyl cations. 2. The reaction of the iridium hydride complexes with trityl cations is accompanied by the formation of trityl radicals.

Cation-anion combination reactions. 19. Some reactions of ortho-substituted triarylmethyl cations in water

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCation-anion combination reactions. 19. Some reactions of ortho-substituted triarylmethyl cations in waterCalvin D. Ritchie, A. A. Kamego, P. O. I. Virtanen, and C. KubistyCite this: J. Org. Chem. 1981, 46, 9, 1957–1959Publication Date (Print):April 1, 1981Publication History Published online1 May 2002Published inissue 1 April 1981https://doi.org/10.1021/jo00322a055RIGHTS & PERMISSIONSArticle Views77Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (466 KB) Get e-Alerts Get e-Alerts

One-electron oxidation of closed-shell molecules. Part 1. Oxidative cleavage of para-substituted benzpinacolones by cerium(IV) ammonium nitrate

The stoicheiometry and kinetics of the CeIV oxidation of 1,2,2,2-tetrakis-(p-methoxyphenyl)ethanone (1a) have been investigated at 25.0 °C in acetic acid as solvent by the use of cerium(IV) ammonium nitrate as oxidant. The reaction occurs with the stoicheiometry 2 CeIV+ An3C·CO·An → 2 CeIII+ An3C++ An·CO+(An =p-methoxyphenyl), affording tris-(p-methoxyphenyl)methanol and anisic acid after work-up. The kinetics were monitored by u.v.–visible spectrophotometry of the tris-(p-methoxyphenyl)methyl cation, showing that the rate-determining step is first order in each reactant. Evidence was found for the formation of p-methoxybenzoyl radical by means of spin-trapping with 2,3,5,6-tetrakis(trideuteriomethyl)nitrosobenzene. The rate constants at 25.0 °C, the oxidation potential, as measured by cyclic voltammetry, and the charge transfer energy with tetracyanoethylene have been measured for five para-substituted benzpinacolones (substituents MeO, Me, and Cl), including (1a). A good correlation of the logarithms of the rates with the oxidation potentials or with the charge transfer energies was found, indicating that a single electron-transfer step between the substrate and CeIV is rate determining. The formation of a radical cation of the benzpinacolone in the rate-determining step and subsequent rapid cleavage into the triarylmethyl cation and the aroyl radical are proposed as a possible mechanism.

A study of the reactions of alkyl compounds of mercury and group IVb elements with triarylmethane salts by PMR spectroscopy

1. The methods of PMR spectroscopy have been used to study the reactions of dipropylmercury, di-n-butylmercury, tetraethyltin, tetrapropyltin, and diisobutylgermanium with triarylmethane salts. 2. Hydride displacement from the metalorganic compound to the triarylmethyl cation proceeds in phase with the breaking of the carbon-metal and β-carbon-hydrogen bonds.

ChemInform Abstract: CATION‐ANION COMBINATION REACTIONS PART 12, RATES, EQUILIBRIA, AND ACTIVATION PARAMETERS FOR REACTIONS OF TRIARYLMETHYL CATIONS IN AQUEOUS SOLUTION

Chemischer InformationsdienstVolume 6, Issue 21 Article ChemInform Abstract: CATION-ANION COMBINATION REACTIONS PART 12, RATES, EQUILIBRIA, AND ACTIVATION PARAMETERS FOR REACTIONS OF TRIARYLMETHYL CATIONS IN AQUEOUS SOLUTION CALVIN D. RITCHIE, CALVIN D. RITCHIESearch for more papers by this authorD. J. WRIGHT, D. J. WRIGHTSearch for more papers by this authorDER-SHING HUANG, DER-SHING HUANGSearch for more papers by this authorA. A. KAMEGO, A. A. KAMEGOSearch for more papers by this author CALVIN D. RITCHIE, CALVIN D. RITCHIESearch for more papers by this authorD. J. WRIGHT, D. J. WRIGHTSearch for more papers by this authorDER-SHING HUANG, DER-SHING HUANGSearch for more papers by this authorA. A. KAMEGO, A. A. KAMEGOSearch for more papers by this author First published: May 27, 1975 https://doi.org/10.1002/chin.197521118AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume6, Issue21May 27, 1975 RelatedInformation

Cation-anion combination reaction. XII. Rates, equilibriums, and activation parameters for reactions of triarylmethyl cations in aqueous solution

Cation-anion combination reaction. XII. Rates, equilibriums, and activation parameters for reactions of triarylmethyl cations in aqueous solution

Cation-anion combination reactions. V. Correlation of reactivities of nucleophiles with diazonium ions and with triarylmethyl cations

Cation-anion combination reactions. V. Correlation of reactivities of nucleophiles with diazonium ions and with triarylmethyl cations

Photo-oxidation of triarylmethanes sensitised by carbonium ions

Absorption of light by stable carbonium ions (xanthydryl, triphenylmethyl, and 5H-dibenzo[a,d]cycloheptenyl cations) in solution in trifluoroacetic acid containing oxygen brings about oxidation of triarylmethanes to the corresponding triarylmethyl cation. Excess of molecular oxygen inhibits the photo-oxidation. The dependence of the quantum yield for photo-oxidation on the concentration of triarylmethane indicates that the hydrocarbon reacts directly with an excited state, believed to be triplet, of the sensitising cation. The effect of ring substituents in triphenylmethane on the partitioning of the triplet sensitiser between oxygen quenching and reaction with the hydrocarbon is interpreted as evidence that the photo-oxidation is initiated by electron transfer from triaylmethane to the excited sensitiser.

Nuclear magnetic resonance studies of chirality in triarylmethyl cations. Mechanism of enantiomer and diastereomer interconversion

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNuclear magnetic resonance studies of chirality in triarylmethyl cations. Mechanism of enantiomer and diastereomer interconversionJ. W. Rakshys Jr., S. V. McKinley, and H. H. FreedmanCite this: J. Am. Chem. Soc. 1971, 93, 24, 6522–6529Publication Date (Print):December 1, 1971Publication History Published online1 May 2002Published inissue 1 December 1971https://doi.org/10.1021/ja00753a032RIGHTS & PERMISSIONSArticle Views84Altmetric-Citations22LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (969 KB) Get e-Alerts Get e-Alerts

Reactions of phthalides and phthaleins in concentrated sulphuric acid

The triarylmethyl cations produced by protonation of 3,3-diphenylphthalide and the phenolphthaleins are stable in aqueous sulphuric acid solutions but undergo further reaction in dilute oleum solutions. Cryoscopy, conductivity, and spectrophotometry show that 3,3-diphenylphthalide undergoes an irreversible cyclodehydration reaction to form 10-hydroxy-10-phenylanthracen-9-one and that the phthaleins undergo a reversible sulphation reaction resulting in closure of the lactone ring and consequently loss of colour. Phenolphthalein and 10-hydroxy-10-phenylanthracen-9-one also disulphonate in 99·9% H2SO4 and in oleums.

Nuclear magnetic resonance studies of chirality in triarylmethyl cations. Mechanism of enantiomer and diastereomer interconversion

Nuclear magnetic resonance studies of chirality in triarylmethyl cations. Mechanism of enantiomer and diastereomer interconversion

The Conformational Preference of the Cyclopropyl Substituent in Triarylmethyl Cations

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Conformational Preference of the Cyclopropyl Substituent in Triarylmethyl CationsThomas Sharpe and J. C. MartinCite this: J. Am. Chem. Soc. 1966, 88, 8, 1815–1817Publication Date (Print):April 1, 1966Publication History Published online1 May 2002Published inissue 1 April 1966https://doi.org/10.1021/ja00960a042RIGHTS & PERMISSIONSArticle Views32Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (353 KB) Get e-Alerts Get e-Alerts

171. Acylation and allied reactions catalysed by strong acids. Part IX. The ease of formation and reactions of the diphenylmethyl and some triarylmethyl cations

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