87901-53-9Relevant academic research and scientific papers
Ambident reactivities of formaldehyde n,n-dialkylhydrazones
Maji, Biplab,Troshin, Konstantin,Mayr, Herbert
, p. 11900 - 11904 (2013/11/19)
What can attack at carbon? With a nucleophilicity N≈7 for attack at the azomethine carbon, formaldehyde hydrazones can undergo noncatalyzed reactions at room temperature with electrophiles that have a reactivity parameter E that is greater than -12. Copyright
Nucleofugality and nucleophilicity of fluoride in protic solvents
Nolte, Christoph,Ammer, Johannes,Mayr, Herbert
experimental part, p. 3325 - 3335 (2012/06/17)
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.
Carbon-13 Nuclear Magnetic Resonance Studies of Carbocations. 10. Variation of Cationic Carbon Chemical Shifts with Increasing Electron Demand in 1,1-Diaryl-1-methyl (Benzhydryl) Carbocations
Kelly, David P.,Jenkins, Margot J.
, p. 409 - 413 (2007/10/02)
A series of 28 1-X-phenyl-1-Z-phenyl-1-methyl (benzhydryl) carbocations, where the X and Z substituents have been varied over the range of electron demand (3,4-CH2CH2O, 11; 4-OCH3, 12; 4-CH3, 13; 4-F, 14; 4-H, 1; 4-CF3, 15; 3,5-(CF3)2, 16), have been prepared from the corresponding alcohols by ionization in superacids and their 13C NMR spectra recorded at low temperatures (-70 to -10 deg C).Plots of the substituent chemical shifts of the cationic carbons (ΔδC+) at -70 deg C against ?C+ are linear for the electron donors (Z = 3,4-CH2CH2O to Z = H) of 13 - 16 and 1 but deviate upward from this correlation line (relative shielding) for the electron acceptors (Z = H to Z = 3,5-(CF3)2).The plots of the highly stabilized cations 11 and 12 approximate shallow curves where groups more electron demanding than 4-CH3 cause relative shielding of the cationic carbon.All these plots are interpreted in terms of competing resonance and localized inductive ?-polarization effects.
