The Ever-Surprising Chemistry of Boron: Enhanced Acidity of Phosphine⋅Boranes
作者:Marcela Hurtado、Manuel Yánez、Rebeca Herrero、Andrés Guerrero、Juan Z. Dávalos、José-Luis M. Abboud、Brahim Khater、Jean-Claude Guillemin
DOI:10.1002/chem.200802307
日期:2009.4.27
The acidity‐enhancing effect of BH3 in gas‐phase phosphine⋅boranes compared to the corresponding free phosphines is enormous, between 13 and 18 orders of magnitude in terms of ionization constants. Thus, the enhancement of the acidity of protic acids by Lewis acids usually observed in solution is also observed in the gas phase. For example, the gas‐phase acidities (GA) of MePH2 and MePH2⋅BH3 differ
The ionic hydrogen bond and ion solvation. 7. Interaction energies of carbanions with solvent molecules
作者:Michael. Meot-Ner
DOI:10.1021/ja00220a022
日期:1988.6
The bondingenergy of a water molecule to carbanions ranges from 11.0 kcal/mol for c-C/sub 5/H/sub 5//sup -/ to 13-15 kcal/mol for CH/sub 2/CH/sup -/, CH/sub 2/CHO/sup -/, and CH/sub 2/COCH/sub3//sup -/ and to 16.2 kcal/mol for HCC/sup -/. Alcohols bond to c-C/sub 5/H/sub 5//sup -/ more strongly, by up to 20.6 kcal/mol for the strongly acidic CF/sub 3/CH/sub 2/OH, and the attachment energies show
A novel and convenient strategy is described for the regioselective conversion of N,N′-disubstituted thioureas and 1,2-dielectrophiles into the highly biologically valuable 2-imino-thiazoline and 2-imino thiazolidine-4-one derivatives. The synthesis proceeds through a process with good yield promoted by an electrogenerated base (EGB) obtained with high current efficiency.
作者:Sean Moran、H. Benton Ellis、D. J. DeFrees、A. D. McLean、Suzanne E. Paulson、G. Barney Ellison
DOI:10.1021/ja00254a019
日期:1987.9
Photoelectron spectroscopy has been used to measure the electron affinities of the isocyanomethyl radicals: EA(CH/sub 2/NC) = 1.059 +/- 0.024 eV and EA(CD/sub 2/NC) = 1.070 +/- 0.024 eV. A Franck-Condon analysis of their spectra suggests that the isocyanomethide anion (/sup -/CH/sub 2/NC) is a pyramidal species and a localized ion. This ion is bent out of the plane by 56 +/- 5/sup 0/ with an inversion
Formation of fluoren-9-ylidenesuccinonitrile by addition of electrogenerated<sup>–</sup>CH<sub>2</sub>CN anions to fluoren-9-one and flouren-9-ylideneacetonitrile
When âCH2CN anions are electrogenerated in acetonitrile addition occurs to fluoren-9-one (FICO) or fluoren-9-ylideneacetonitrile (FICCHCN) to give the condensation of fluorenone and succinonitrile have failed.