25076-72-6Relevant academic research and scientific papers
Stabilities of Halonium Ions from a Study of Gas-Phase Equilibria R(1+)+XR'=(RXR')(1+)
Sharma, Dilip K. Sen,Hoejer, Sarah Meza de,Kebarle, Paul
, p. 3757 - 3762 (1985)
The gas-phase ion equilibria R(1+)+B=RB(1+), where R(1+)=Et(1+), i-Pr(1+), c-Pe(1+), t-Bu(1+), 2-Me-2-Bu(1+), and 2-Nb(1+) and B=CH3Cl, CH2Cl2, CHCl2, CHCl3, SO2F2, CF3H, and CF4 were determined in a pulsed electron beam high pressure mass spectrometer. van't Hoff plots provide ΔG0300, ΔH0, and ΔS0.For the chloronium ions the following trends were observed.The bond energy D(R(1+)-ClR0), where R(1+) changes and R0 is constant, decreases with increasing electronic stabilization of R(1+), i.e., in the order Me(1+), Et(1+), i-Pr(1+), c-Pe(1+), t-Bu(1+), Nb(1+).The same order was observed earlier in this laboratory for D(R(1+)-Cl(1-)), i.e., the chloride affinity of R(1+).However, the changes of D(R(1+)-ClR0) for R(1+)=2-Me-2-Bu(1+), Nb(1+), and t-Bu(1+) are very small.This means that little differential, specific nucleophilic solvation of these ions in solution is to be expected when solvents of low nucleophilicity like CH2Cl2 and SO2ClF are used.The bond energies D(Me(1+)-ClR) increase in the order R=Me, Et, i-Pr, t-Bu.The bond energies D(t-Bu(1+)-B) decrease in the order B=C2H5Cl, CH2Cl2 ca.CH3Cl, CCl3H, SO2F2, CF3H, CF4.The significance of these trends is discussed.
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
Shin, Seung Koo,Beauchamp, J. L.
, p. 900 - 906 (2007/10/02)
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.
