Series of Protonated Nitrogen Bases with a Weakly Coordinating Counteranion: Observation of the 14N–1H Spin–Spin Coupling

Abstract

A distinguished triplet splitting pattern for the ¹⁴N–¹H couplings in the proton signals of a series of protonated nitrogen bases─aliphatic and aromatic amines, as well as pyridines─with the weakly coordinating tetrakis(pentafluorophenyl)borate anion, [B(C₆F₅)₄]⁻, is observed for the first time in nonaqueous media at room temperature. The effects of ion pairing, solvent parameters, and correlation between the δ_H, ¹J_NH, and pK_a values are reported.