Thermodynamic basicity vs. kinetic basicity of diazoles (imidazoles and pyrazoles)

摘要: The intrinsic basicity of 24 azoles (pyrazoles, indazoles, imidazoles, benzimidazoles) and 7-methylazaindole was determined by mass spectrometry techniques, ion cyclotron resonance (ICR) and/ or chemical ionization (CI) in conjunction with tandem (MS/MS). A reasonably good agreement (r 2 =0.967) is found between both methods (15 compounds). Thus, it possible to use CI/MS/MS determine the compounds not measurable ICR for purity volatility reasons. Some anomalies are interpreted terms entropy steric effects. data also discussed using empirical models (σα, σ R ) chelation annelation effects