Boronic acid-appended bis-viologens as a new family of viologen quenchers for glucose sensing

A new family of boronic acid-appended viologen quenchers has been synthesized containing two viologen subunits in a single quencher moiety. Relative to the single viologen-based quenchers previously developed in our laboratory, the bis-viologen ortho-boronic acid (BoB) compounds, in combination with the fluorescent dye, HPTS, display greatly enhanced Stern–Volmer quenching constants and much greater signal modulation in response to glucose. The superior performance is realized at lower quencher-to-dye ratios than are required for the single-viologen systems.