Preparation and Comparison of Chemical Properties of Phenazasiline Monomer, Dimer, Trimer, and Polymer

For the synthesis of phenazasiline with various degree of polymerization, phenazasilinediboronic acid esters (B‐Phz‐Bs) were prepared. Each absorption λmax of B‐Phz‐Bs was observed at longer wavelength than that of corresponding dibromophenazasiline derivatives (Br‐Phz‐Br). Reactions of B‐Phz‐B with monobromophenazasiline and Br‐Phz‐Br gave terphenazasiline (Me‐3Phz‐Mes) and poly(phenazasiline) (PPhz), respectively. The optical and electrochemical properties of phenazasilines with various degrees of polymerization were also studied. The absorption λmax of the compound with higher degree of polymerization was observed at longer wavelength. Cyclic voltammetry (CV) of monophenazasiline showed a one‐step reversible redox process. On the other hand, CVs of biphenazasiline and poly(phenazasiline) showed two‐step reversible redox process and that of terphenazasiline showed three‐step reversible redox process, respectively. New series of phenazasiline diboronic acid esters (B‐Phz‐Bs) were prepared. B‐Phz‐Bs show unique optical properties due to the intra‐molecular π‐B interaction. The reactions of B‐Phz‐B with monobromo‐phenazasiline (Me‐Phz‐Br) gave terphenazasilines (Me‐3Phz‐Me), and Br‐Phz‐Br gave poly‐(phenazasiline) (PPhz), respectively. The effect of the degree of polymerization of phenazasiline derivatives on chemical and electrochemical properties was estimated.