Synthesis and Physical Properties of Strained Doubly Phosphorus‐Bridged Biaryls and Viologens

Abstract New P/N‐containing π‐electron systems comprising fully planar biaryl arrays are synthesized by multiple radical phosphanylation. The biaryl moiety in these highly strained planar π‐systems is rigidified by double P‐bridging. The electronic properties of the core biaryl entity are varied by introducing N‐donor substituents or by installing N‐atoms within the π‐system, thereby moving to the viologen core structure. The electrochemical and photophysical properties of these compounds are discussed and compared with those of related systems.