ACIDITY, BASICITY, AND THE STABILITY OF HYDROGEN-BONDS - COMPLEXES OFRO-+HCF3

Ion-molecule complexes of RO- (R = Me, Et, i-Pr) and HCF3 have been st udied with Fourier transform ion cyclotron resonance spectrometry. The RO- complexation energies with HCF3 were measured relative to RO-. H2 O. These complexes, [ROHCF3](-), have complexation energies on the ord er of -20 kcal/mol and have low deuterium fractionation factors and ar e, therefore, hydrogen bonded. The structure of the complexes was stud ied by isotopic equilibrium experiments and ab initio calculations. Al l of the complexes studied have the structure RO-. HCF3 even when HCF3 is a stronger acid than ROH. The structure of the complexes can be un derstood through electrostatic arguments rather than the difference in acidity between the ion and neutral.