How Strong and How Hindered Can Uncharged Phosphazene Bases Be?

Abstract

Unequivocal answers to the questions in the title are not possible yet, but the strongest stable uncharged base, the PS compound 1, is 28-29 pK units more basic than triethylamine. Compound 1 is easily prepared, readily soluble, and can be stored almost indefinitely at room temperature in the absence of moisture.