57669-14-4

Upstream product

• 6711-19-9 benzylium cation 
• 104-82-5 4-Methylbenzyl chloride 
• 104-81-4 4-Methylbenzyl bromide 
• 64710-12-9 dimethylfluoronium ion 
• 60-15-1 2-amino-1-phenylpropane 
• 108-88-3 toluene 
• 106-42-3 para-xylene 
• 28965-62-0 dimethylsilanylium 

Downstream Products

• 106-42-3 para-xylene 
• 28965-62-0 dimethylsilanylium 
• 104-82-5 4-Methylbenzyl chloride 
• 128408-23-1 C₉H₇F₄O⁽¹⁺⁾ 
• 128408-22-0 C₉H₇ClF₃O⁽¹⁺⁾ 
• 128408-25-3 C₉H₇ClF₃S⁽¹⁺⁾ 

Relevant academic research and scientific papers

Kinetic hydricity of silane hydrides in the gas phase

Herein, gas phase studies of the kinetic hydricity of a series of silane hydrides are described. An understanding of hydricity is important as hydride reactions figure largely in many processes, including organic synthesis, photoelectrocatalysis, and hydrogen activation. We find that hydricity trends in the gas phase differ from those in solution, revealing the effect of solvent. Calculations and further experiments, including H/D studies, were used to delve into the reactivity and structure of the reactants. These studies also represent a first step toward systematically understanding nucleophilicity and electrophilicity in the absence of solvent.

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.

Site of Gas-phase Methylation of 1-Phenyl-2-aminopropane

The regioselectivity of methyl cation transfer from (CH3)2F(1+), (CH3)2Cl(1+) and (CH3)3O(1+) to 1-phenyl-2-aminopropane was studied by Fourier transform ion cyclotron resonance in combination with collision-induced dissociation and neutralization-reionization mass spectrometry of the stable (1+) ions formed in a chemical ionization source.The (CH3)2F(1+) ion transfers a methyl cation to the NH2 group and the phenyl ring with almost equal probability.Predominant CH3(1+) transfer to the NH2 group is observed for the (CH3)2Cl(1+) ion whereas the (CH3)3O(1+) ion reacts almost exclusively at the amino group.The preference for m ethylation at NH2 is discussed in terms of a lower methyl cation affinity of the phenyl ring than of the amino group and the existence of an energy barrier for methylation of the phenyl moiety.

Precise Determination of Stabilities of Primary, Secondary, and Tertiary Silicenium Ions from Kinetics and Equilibria of Hydride-Transfer Reactions in the Gas Phase. A Quantitative Comparison of the Stabilities of Silicenium and Carbonium Ions in the Gas Phase

Fourier transform ion cyclotron resonance spectroscopy has been used to examine kinetics and equilibria of hydride-transfer reactions of methyl-substituted silanes with various hydrocarbons having well-established gas-phase hydride affinities.The derived hydride affinities, D(R3Si(1+)-H(1-)), for the silicenium ions SiMeH2(1+), SiMe2H(1+), and SiMe3(1+) are 245.9, 230.1, and 220.5 kcal/mol, respectively, to be compared with the values of 270.5, 251.5, and 233.6 kcal/mol for the corresponding carbonium ions.This indicates that the silicenium ions are significantly more stable than the corresponding carbonium ions in the gas phase with H(1-) as a reference base.

Substituent Effect on the Stability of Benzyl Cation in the Gas Phase

Chloride ion affinities of substituted benzyl cations in the gas phase have been determined by means of an ICR mass spectrometer.The substituent effect has been analyzed in terms of the LArSr Eq., giving a p=13.6 and r+=1.31.

Kinetics and Equilibria of Chloride Transfer Reactions. Stabilities of Carbocations Based on Chloride and Hydride Transfer Equilibria Measurements

The kinetics of a number of gas-phase chloride transfer reactions R0(1+)+RCl=R0Cl+R(1+) were measured with a pulsed electron high pressure mass spectrometer.Most of the reactions were found to occur near the collision limit, i.e., with rate constants k ca. 10-9 molecules-1 cm3 s-1.However, several reactions were much slower and were exhibiting negative temperature dependence, i.e., decreasing rate with increasing temperature.Hydride and chloride transfer equilibria were determined for various carbocations R(1+) (R=isopropyl, cyclopentyl, tert-butyl, 1-methylcyclopentyl, substituted benzyls, norbornyl, 2-methyl-2-norbornyl, and adamantyl).Excellent agreement with earlier hydride transfer measurements of Solomon, Meot-Ner, and Field were observed.The chloride affinities generally support conclusions based on the hydride transfer data.Discussion of the data in connection with benzyl cation substituent effects, the norbornyl cation stability, and solvent effects on carbocation stability is presented.The data show that the 2-norbornyl cation is unusually stable.Significant differences between carbocation R(1+) stabilities in gas phase and solution are found which suggest that both differential nucleophilic solvent stabilization and differential nonspecific solvation occur in solution.