3,10-Diaryl Phenothiazines – One-pot Synthesis and Conformational Tuning of Ground and Excited State Electronics

Abstract

A broad series of electronically diverse 3,10-diaryl phenothiazines was readily synthesized by a sequentially Pd-catalyzed three-component arylation-amination synthesis in a one-pot fashion in moderate to excellent yields. The diversity-oriented modular nature of the multicomponent reaction concept enables comprehensive investigations of electronic properties of the title compounds by absorption and emission spectroscopy, cyclic voltammetry, and quantum chemical calculations to elucidate their electronic structure. The electronic properties can be fine-tuned by the fundamental conformational change from intra to extra configuration as well as by introducing different remote electronic substituents. Physical-organic treatment of the electronic data of a consanguineous series of this library allows establishing semiquantitative linear free energy relationships (LFERs), eventually as a 3D plot for the first oxidation potentials, paves the way to a rational design of tailored 3,10-diaryl phenothiazines with predictable oxidation potentials and photophysical properties.