Proton sponges and superbases with nitrogen, phosphorus, arsenic, oxygen, sulfur, and selenium as proton acceptor sites

Abstract

Charge delocalization and intramolecular hydrogen bond formation in the protonated forms of organic bases with nitrogen, phosphorus, arsenic, oxygen, sulfur, and selenium as proton acceptor sites were investigated using B3LYP/6-311++G(d,p) method. Although the superbases with P and As atoms as proton acceptor site showed higher ability to delocalize the charge of the entering proton, because of the inherent basicity of nitrogen, the superbases with nitrogen atom were stronger bases. Proton sponges with N and O sites formed strong NH…N and OH…O hydrogen bonds. Generally, both the superbases and proton sponges with nitrogen atom as proton acceptor site exhibit higher basicity.