Gas-phase basicity of polyfunctional amidinazines: experimental evidence of preferred site(s) of protonation
Gas-phase basicities of four polyfunctional N1,N1-dimethyl-N2-azinylformamidines (1-4) are obtained from proton-transfer equilibrium constant determinations, using Fourier transform ion-cyclotron resonance mass spectrometry. Comparison with model amidines and azines (GB revised according to the recent compilation of Hunter and Lias) indicates the aza group as the favored site of protonation. The strong basicity of ortho derivatives is explained in term of intramolecular stabilization (the so-called "internal solvation").
Raczynska
ED
Department of Chemistry, Agricultural University (SGGW), Warszawa, Poland. raczynskae@delta.sggw.waw.pl
Decouzon
M
Gal
JF
Maria
PC
Taft
RW
Anvia
F