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Upstream product

• 530-48-3 1,1-Diphenylethylene 
• 497956-56-6 protonated trimethyl phosphate 
• 599-67-7 1,1-diphenylethanol 
• 59341-20-7 3-methyl-3-phenyl-3H-indazole 
• 5558-66-7 2,2-diphenylpropanoic acid 
• 14593-41-0 1,1,3-Triphenyl-1,3-propanediol 

Downstream Products

• 530-48-3 1,1-Diphenylethylene 
• 497956-56-6 protonated trimethyl phosphate 
• 599-67-7 1,1-diphenylethanol 

Relevant academic research and scientific papers

1,1-Diphenylethylene adsorbed onto acid zeolites: Nature of the blue (605-nm) species

Diffuse reflectance spectra of HY (Si/Al 15) and Hβ (Si/Al 13) zeolites after adsorption of 1,1-diphenylethylene (DPE) show an intense 605-nm absorption band characteristic of an elusive blue species observed a long time ago for DPE-silica-alumina solids. This blue species was wrongly attributed to the corresponding DPE+. radical cation or a complex of DPE with Lewis sites of these solids. In our case, EPR spectra of DPE samples adsorbed on HY and Hβ zeolites indicate that the spin population of these samples is too low (15 spin · g-1) to contain significant amounts of any paramagnetic species. In addition, IR spectra of the organic material incorporated within HY and Hβ is very similar to those of some DPE dimers. Product studies after solid-liquid extraction of zeolites and silica-alumina in which DPE has been adsorbed also show the formation of the corresponding dimers derived from the acid-catalyzed mechanism. Variable amounts of oxidation products are also formed when the adsorption is carried out in the open air. In addition, 13C-NMR spectra in solution of blue samples generated by treatment of DPE with sulfuric acid in dimethyl sulfate also indicate the presence of the same dimer distribution and the absence of detectable low-field signals that could be attributed to any carbenium ion. With these data, it is clear that in spite of the intense color developed in these samples, the bulk of the organic material adsorbed on the zeolites does not correspond to any intermediate, but to dimers. Semiempirical ROHF calculations using the ZINDO program provide some support to the possibility that the blue color could be due to 1,1,3,3-tetraphenyl-1-butylium cation, the reaction intermediate involved in the DPE dimerization mechanism.

Search for long-lived 1,3-carbodications and preparation of the persistent 1,1,3,3-tetracyclopropyl-1,3-propanediyl dication

Several substituted versions of 1,3-propanediol were ionized under a variety of superacidic conditions, and the product carbocations and carboxonium species were characterized by 13C NMR spectroscopy at low temperatures. 1,1,3-Triphenyl-1,3-pro

Straightforward formation of carbocations from tertiary carboxylic acids: Via CO release at room temperature

We report an unprecedented mode of reactivity of carboxylic acids. A series of tertiary carboxylic acids, containing at least one phenyl α-substituent, undergo loss of carbon monoxide at room temperature (295 K), by a one pot reaction with 0.5-1 molar equivalents of WCl6 in dichloromethane. A plausible mechanism for the Ph3CCO2H/WCl6 reaction, leading to [CPh3][WOCl5] and Ph3CCl, is proposed on the basis of DFT calculations. The analogous reactions involving CEt(Ph)2CO2H, CMe(Ph)2CO2H and CMe2(Ph)CO2H selectively afforded stable hydrocarbons (alkene or indene, depending on the case), apparently resulting from the rearrangement of elusive tertiary carbocations.

Rates of C-S bond cleavage in tert-alkyl phenyl sulfide radical cations

Radical cations of tert-alkyl phenyl sulfides 1-4 have been generated photochemically in MeCN in the presence of the N-methoxyphenanthridinium cation (MeOP+), and the rates of C-S bond cleavage have been determined by laser flash photolysis.

Lifetimes and UV-visible absorption spectra of benzyl, phenethyl, and cumyl carbocations and corresponding vinyl cations. A laser flash photolysis study

Benzyl (4-MeO, 4-Me, and 4-methoxy-1-naphthylmethyl), phenethyl (4- Me2N, 4-MeO, 3,4-(MeO)2, 4-Me, 3-Me, 4-F, 3-MeO, 2,6-Me2, parent, and 4- methoxy-1-naphthylethyl) and cumyl (4-Me2N, 4-MeO, 4-Me, parent) cations have been studied by laser flash photolysis (LFP) in 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP). In most cases styrene or α-methylstyrene precursors were employed for the phenethyl and cumyl ions, the intermediate being obtained by solvent protonation of the excited state. Benzyl cations were generated by photoheterolysis of trimethylammonium and chloride precursors. While a 4-MeO substituent provides sufficient stabilization to permit observation of cations in TFE, cations with less stabilizing substituents usually require the less nucleophilic HFIP. Even in this solvent, the parent benzyl cation is too short-lived (lifetime 6H4C+(R)-CH3 (R = Me, Et, i-Pr, t-Bu, cyclopropyl, C6H5, 4-MeOC6H4) were generated in TFE via the photoprotonation route. The alkyl series shows that steric effects are important in the decay reaction. The cation with R = cyclopropyl is a factor of 1.5 less reactive than the cation where R = phenyl. Several vinyl cations have also been generated by photoprotonation of phenylacetylenes. ArC+=CH2 has a reactivity very similar to that of its analog ArC+H-CH3, the vinyl cation being slightly (factors of 2-5) shorter-lived. For the various series of cations, including vinyl, substituents in the aryl ring have a consistent effect on the κ(max), a shift to higher wavelength relative to hydrogen of 15 nm for 4-Me, 30 nm for 4-MeO, and 50 nm for 4-Me2N.

Photochemistry of 3H-indazoles in protic media. Benzyl cations via protonation of 2-methylene-3,5-cyclohexadienylidenes

Photolysis of 3,3-disubstituted 3H-indazoles in protic media (ROH) gives rise to benzyl ethers, in addition to hydrocarbons (derivatives of benzocyclopropene, styrene, and fluorene) which are also found in aprotic solvents. In the presence of ROD, the benzyl ethers are formed with incorporation of deuterium into the ortho position, pointing to protonation of 2-methylene-3,5-cyclohexadienylidenes. Laser flash photolysis of 3H-indazoles generates diazo compounds and benzyl cations as transient intermediates.

Experiments and calculations for determination of the stabilities of benzyl, benzhydryl, and fluorenyl carbocations: Antiaromaticity revisited

The following pKR values for the formation of benzyl, benzhydryl, and fluorenyl carbocations in 50:50 (v:v) trifluoroethanol/water at I = 0.50 (NaClO4) were determined as pKR = -log (kHOH[H2O]/kH), where kH is the second-order rate constant for acid-catalyzed reaction of the alcohol to form the carbocation and kHOH is the second-order rate constant for capture of the carbocation by water: (R+, pKR); PhCH2+, ≤-20; PhCH(Me)+, -15.4; PhC(Me)2+, -12.3; Ph2CH+, -11.7; Ph2C(Me)+, -9.3; 9-fluorenyl carbocation (9-Fl+), -15.9; 9-methyl-9-fluorenyl carbocation (9-Me-9-Fl+), -11.1. The pKR for Ph2CH+ is in fair agreement with the value estimated using acidity functions,1a but the pKR for 9-Me-9-Fl+ is ca. 4 units more positive than that from the acidity function method,1a so that the difference in the acidity of benzhydryl and fluorenyl carbocations is smaller than estimated in earlier work. The 12 π-electron cyclic fluorenyl system in 9-Fl+ and 9-Me-9-Fl+ causes only 5.7 kcal/mol and 2.4 kcal/mol, respectively, destabilization of the corresponding acyclic carbocations Ph2CH+ and Ph2C(Me)+. The pKR values show that "antiaromatic" destabilization of the 9-fluorenyl carbocations must be small. Ab initio calculations of the structures and energies of 9-Fl+ and Ph2CH+ and of the corresponding alcohols at the 3-21G//3-21G and 6-31G*//3-21G levels indicate that Ph2CH+ is ca. 8-10 kcal/mol more stable than 9-F1+, which is in good agreement with the stability difference calculated from the pKR data. This indicates that electronic factors play the major role in determining the relative energies of these carbocations. Force field calculations were performed to estimate the contribution of van der Waals and ring strains to the difference in the pKR values for Ph2CH+ and 9-Fl+. Assuming hypothetical structures for Ph2CH+ and 9-Fl+ which are free of van der Waals and ring strains, it is then estimated that there is an 8-11 kcal/mol decrease in π-electron stabilization on moving from Ph2CH+ (C2v) and 9-F1OH to 9-Fl+ and Ph2CHOH. It is concluded that 9-fluorenyl carbocations are not antiaromatic. The difference in the energy of the 9-fluorenyl and benzhydryl carbanions relative to the alcohols was calculated to be -13.2 kcal/mol at the 6-31G*//3-21G level. This difference is attributed to the difference in the energies of the HOMOs for the two carbanions.

Stabilities of Carbocations in Solution. 14. An Extended Thermochemical Scale of Carbocation Stabilities in a Common Superacid

Until now, thermodynamic stabilities of carbocations have been limited to (1) relatively stable resonance delocalized ions which are ranked on the pKR scale and (2) relatively unstable aliphatic and alicyclic ions which have been compared in the gas phase by ion cyclotron resonance or by calorimetry in SbF5/SO2ClF superacid at -50 to -120 deg C in our laboratory.The present paper will present an extensive series of new measurements which is designed to close the gap between the stable triarylmethyl cations and the unstable ions so as to put them all on a common energy scale.Carbinols were used as precursors in SbF5/HSO3F/SO2ClF at -40 deg C.As we reported recently (J.Am.Chem.Soc., 104, 3522(1982)), these conditions are necessary to avoid complications which appear to be introduced by ion-pairing when the alcohols are treated with the SbF5/SO2ClF system which was used previously to ionize alkyl chlorides.The results from the present work place 39 typical carbocations representing saturated, secondary, and tertiary, and aliphatic, bicyclic, and substituted cumyl, benzhydryl, and trityl systems on a common scale.Correlations and interpolation equations for relating other measurements in the gas phase and solution will be presented.The results provide useful comparisons of the ?+ and ?C+ scales for correlating carbocation stabilities and provide new data for several classic questions in the field such as the ranking of methyl, phenyl, and cyclopropyl groups for stabilizing ions and also the reactions of carbocations with water.

Properties and Reactions of Trimethyl Phosphite, Trimethyl Phosphate, Triethyl Phosphate, and Trimethyl Phosphorothionate by Ion Cyclotron Resonance Spectroscopy

The gas-phase ion-molecule reactions occurring in trimethyl phosphite, trimethyl phosphate, triethyl phosphate, and trimethyl phosphorothionate have been investigated by ion cyclotron resonance spectroscopy.Protonated parent ions, tetracoordinated phosphonium ions, and cluster ions are the reaction products observed.The proton affinities of these compounds have been determined to be 222.9, 214.2, 218.7, and 216.6 kcal/mol, respectively (relative to PA(NH3) = 207.0 kcal/mol).Homolytic bond dissociation energies of the protonated species are calculated using adiabatic ionization potentials determined by photoelectron spectroscopy.The trends in these quantities are discussed.A reasonable value for the correlated homolytic bond dissociation energy of trimethyl phosphite indicates that the first ionization potential of this molecule should be assigned to the phosphorus lone pair.The application of chemical ionization mass spectrometry to the analysis of phosphorus esters is briefly discussed.