Persistent Radical Pairs Between N-Substituted Naphthalimide and Carbanion Exhibit pKa-Dependent UV-vis Absorption

A new strategy is constructed for estimating and screening pKa values among different carbon acids under ambient conditions via the UV-vis absorption spectrum of persistent radical pair originating from an N-substituted naphthalimide (NNI) derivative in the presence of various carbanions in organic solutions