58493-75-7

Upstream product

• 1143-91-5 bis(4-methylphenyl)diazomethane 
• 116664-90-5 4-(di-p-tolylmethoxy)benzonitrile 
• 32076-77-0 4,4'-dimethyldiphenylcarbene 
• 40673-57-2 1,1,2,2-tetra(p-tolyl)ethane 
• 13389-70-3 bis(4-methylphenyl)methyl chloride 
• 4957-14-6 4,4'-dimethyldiphenylmethane 
• 155960-71-7 4,4'-dimethylbenzhydryl fluoride 
• 1580541-48-5 4,4'-dimethylbenzhydryl dichloroacetate 
• 1580541-53-2 4,4'-dimethylbenzhydryl trichloroacetate 
• 611-97-2 bis(p-methylphenyl)-methanone 
• 5633-96-5 potassium p-cyanophenoxide 
• 885-77-8 4,4'-dimethylbenzhydrol 

Downstream Products

• 4957-14-6 4,4'-dimethyldiphenylmethane 
• 63795-96-0 CH₃Cl₂Si⁽¹⁺⁾ 
• 32825-42-6 dimethyl-phenyl-silanylium 
• 139732-72-2 phenylsilyl cation 
• 29996-90-5 triphenylsilanylium 
• 120-12-7 anthracene cation radical 
• 34512-27-1 naphthalene radical cation 
• 878162-50-6 4,4'-dimethylphenyl-methyl-isocyanate 
• 108733-06-8 4,4-bis(4-methylphenyl)-1-butene 
• 155960-71-7 4,4'-dimethylbenzhydryl fluoride 
• 52897-99-1 bromo(bis-p-tolyl)methane 
• 68240-81-3 C₁₇H₂₀O 

Relevant academic research and scientific papers

Solvolytic Behavior of Aryl and Alkyl Carbonates. Impact of the Intrinsic Barrier on Relative Reactivities of Leaving Groups

The effect of negative hyperconjugation on the solvolytic behavior of carbonate diesters has been investigated kinetically by applying the LFER equation log k = sf(Ef + Nf). The observation that carbonate diesters solvolyze faster than the corresponding carboxylates and that the enhancement of aromatic carbonates is more pronounced indicates that the negative hyperconjugation and π-resonance within the carboxylate moiety is operative in TS. The plots of ΔG? vs approximated ΔrG° for solvolysis of benzhydryl aryl/alkyl carbonates and benzhydryl carboxylates reveal that a given carbonate solvolyzes over the higher Marcus intrinsic barrier and over the earlier transition state than carboxylate that produces an anion of similar stability. Due to the lag in development of the electronic effects along the reaction coordinate, the impact of the intrinsic barrier on solvolytic behavior of carbonates is more important than in the case of carboxylates and phenolates. Consequently, the solvolytic reaction constants (sf) are generally lower for carbonates than for carboxylates. Because of considerable lower reaction constants of carbonates, an inversion of relative reactivities between aryl/alkyl carbonate and another leaving group of similar nucleofugality (Nf) may occur if the electrofuge moiety of a substrate is switched.

Solvolytic Behavior of Aliphatic Carboxylates

The leaving group abilities (nucleofugalities) of a series of aliphatic carboxylates have been obtained by determining the nucleofuge-specific parameters (Nf and sf) from solvolysis rate constants of X,Y-substituted benzhydryl carboxylates in a series of aqueous ethanol mixtures by applyication of the linear free energy relationship (LFER) equation: log k = sf (Ef + Nf). These values can be employed to compare reactivities of carboxylates with those of other leaving groups previously included in the nucleofugality scale, and also to estimate the solvolysis rates of various carboxylates. It is confirmed that the inductive effect is the most important variable governing the reactivities of halogenated carboxylates in solution. Moreover, both the Hammett correlation and the solvolytic activation parameters have revealed a strong influence of the inductive effect on the nucleofugality of alkyl-substituted carboxylates. The reaction constants (sf) indicate that carboxylate substrates with weaker leaving groups solvolyze via later, more carbocation-like, transition states, which is in accord with the Hammond postulate. In addition, due to the weaker demand for solvation of transition states that produce more strongly stabilized benzhydrylium ions, in which more efficient charge delocalization occurs, the reaction constants (sf) obtained with most of the leaving groups investigated here increase as the polarity of the solvent decreases.

Solvent nucleophilicities of hexafluoroisopropanol/water mixtures

First-order rate constants k1 for the trapping of various donor- and acceptor-substituted benzhydrylium ions in mixtures of 1,1,1,3,3,3- hexafluoro-2-propanol (HFIP) and water ranging from 50 to 99% HFIP (w/w) were determined by laser flash pho

Nucleofugality and nucleophilicity of fluoride in protic solvents

A series of p-substituted benzhydryl fluorides (diarylfluoromethanes) were prepared and subjected to solvolysis reactions, which were followed conductometrically. The observed first-order rate constants k1(25 °C) were found to follow the correlation equation log k1(25 °C) = sf(Nf + Ef), which allowed us to determine the nucleofuge-specific parameters Nf and sf for fluoride in different aqueous and alcoholic solvents. The rates of the reverse reactions were measured by generating benzhydrylium ions (diarylcarbenium ions) laser flash photolytically in various alcoholic and aqueous solvents in the presence of fluoride ions and monitoring the rate of consumption of the benzhydrylium ions by UV-vis spectroscopy. The resulting second-order rate constants k-1(20 °C) were substituted into the correlation equation log k-1 = sN(N + E) to derive the nucleophilicity parameters N and sN for fluoride in various protic solvents. Complete Gibbs energy profiles for the solvolysis reactions of benzhydryl fluorides are constructed.

Nucleophilic reactivities of tertiary alkylamines

The kinetics of the reactions of tertiary amines, triethylamine (1a), N-methylpyrrolidine (1b), N-methylpiperidine (1c), and N-methylmorpholine (1d) with benzhydrylium ions (Ar2CH+) have been studied in acetonitrile and dichlorometha

Generation of diarylcarbenium ion poolsviaelectrochemical C-H bond dissociation

The "cation pools" of diarylcarbenium ions have been generated by the low-temperature electrochemical oxidation of diphenylmethane derivatives. In addition to diphenylmethanes having various substituents, 9,10-dihydroanthracene, dibenzosuberane, and xanth

Ambident reactivity of the cyanate anion

A study was conducted to investigate ambident reactivity of the cyanate anion. The study showed that the cyanate anion is an ambident nucleophile, which may react with electrophiles either at the oxygen terminus, to yield alkyl cyanates, or at the nitrogen terminus, to yield isocyanates. Equal amounts of alkyl cyanates and isocyanates were obtained, when secondary iodoalkynes were treated with silver cyanate and the formation of tert-butyl isocyanate, along with 2-methylpropene and cyanic acid. The study also investigated the possibility of SN1 reactions of cyanates proceeding with charge control to give cyanates.

Photohomolysis and photoionization of substituted tetraphenylethanes and C - C fragmentation of 1,1,2,2-tetra(p-R-phenyl)ethane radical cations (R = H, CH3, OCH3, Cl)

On photolysis of a series of tetraphenylethanes in 2,2,2-trifluoroethanol (TFE) solution with 248 nm light, homolysis of the central C-C bond occurs to yield the corresponding substituted diphenylmethyl radicals, in a process requiring one quantum of light. A second process takes place under conditions of high photon fluxes, namely biphotonic photoionization to produce a radical cation, which subsequently undergoes efficient C-C scission of the aliphatic central bond to yield the radical and carbocation fragments. Photoionization and photohomolysis are the preferred processes of excited state deactivation in the solvents acetonitrile, TFE, and 1,1,1,3,3,3-hexafluoroisopropanol. The lifetime of the radical cation could be directly determined by following the formation rates of the fragments in solution. The cations were characterized by their UV absorption spectra and electrophilic reactivities.On photolysis of a series of tetraphenylethanes in 2,2,2-trifluoroethanol (TFE) solution with 248 nm light, homolysis of the central C - C bond occurs to yield the corresponding substituted diphenylmethyl radicals, in a process requiring one quantum of light. A second process takes place under conditions of high photon fluxes, namely biphotonic photoionization to produce a radical cation, which subsequently undergoes efficient C - C scission of the aliphatic central bond to yield the radical and carbocation fragments. Photoionization and photohomolysis are the preferred processes of excited state deactivation in the solvents acetonitrile, TFE, and 1,1,1,3,3,3-hexafluoroisopropanol. The lifetime of the radical cation could be directly determined by following the formation rates of the fragments in solution. The cations were characterized by their UV absorption spectra and electrophilic reactivities.

Carbocation formation via carbene protonation studied by the technique of stopped-flow laser-flash photolysis

Photolysis of diaryl diazo compounds in the presence of hydroxylic protonating substrates in acetonitrile leads to the formation of the corresponding carbocations. Quantum yields for these processes have been determined for the first time; for example, photolysis of diphenyldiazomethane in 1:1 acetonitrile/trifluoroethanol produces Ph2CH+ with a quantum yield of 0.007. The products, formed either by direct insertion or through the carbocation route, are the corresponding ethers. Kinetics analysis leads to the conclusion that carbocations are formed by protonation of the singlet carbene. Electron-rich substituents enhance carbocation yields; for example, (4-MeOC6H4)2CH+ is produced with a quantum yield of 0:12 in 1:1 acetonitrile/methanol or acetonitrile/trifluoroethanol. Most of the diazo precursors employed decompose rapidly in the presence of acids or strongly protonating solvents. In order to overcome this problem, we have developed the technique of stopped-flow laser-flash photolysis, which permits the study of photoreactions in thermally unstable mixtures. Strong acids (e.g., perchloric) in concentrations up to 10 mM fail to yield any carbocations. This is probably due to the short lifetime of the carbene singlet that cannot be trapped at low acid concentrations, as well as to a low-energy singlet carbene in equilibrium with the triplet following intersystem crossing; higher concentrations of acid induce diazo decomposition within the stopped-flow mixing time.

Photoionization of Diarylmethyl Radicals in Acetonitrile and Alcohol-Water: Laser Flash Production of Diarylcarbenium Ions

Diarylmethyl radicals Ar2CH. were produced by 248-nm laser photolysis (20 ns) of diphenylmethane, diphenylmethanol, and diarylmethyl halides in acetonitrile and water:alcohol mixtures.A few microseconds after their generation, the radicals were