Single-Centered Hydrogen-Bonded Enhanced Acidity (SHEA) Acids: A New Class of Brønsted Acids

Hydrogen bonds are the dominant motif for organizing the three-dimensional structures of biomolecules such as carbohydrates, nucleic acids, and proteins, and serve as templates for proton transfer reactions. Computations, gas-phase acidity measurements, and pK(a) determinations in dimethyl sulfoxide on a series of polyols indicate that multiple hydrogen bonds to a single charged center lead to greatly enhanced acidities. A new class of Brønsted acids, consequently, is proposed.