| Abstract
| - Eleven new phenyl-substituted phosphazenes (P1-, P3-, and P4-bases) have been synthesized bythe Staudinger or the Kirsanov reactions. The UV−vis spectrophotometric titration method wasused to establish the relative basicity of them, and to extend the ion-pair basicity scale for THFmedium. These measurements together with our previous work give a continuous basicity scale inTHF ranging from 2.6 (2-MeO-pyridine) to 26.6 (2-Cl-C6H4P4(pyrr) phosphazene) in pKα units: thatis for 24 orders of magnitude and containing 58 compounds (pyridines, anilines, amines, guanidines,amidines, phosphazenes). Ion-pair formation was taken into account by using the Fuoss equation.ΔpKip values of some phosphazene indicators estimated earlier by the 13C NMR method were revised.For some of the phosphazenes gas-phase basicities were measured.
|
