Improved Synthesis of 2,2‘-Dibromo-9,9‘-spirobifluorene and Its 2,2‘-Bisdonor-7,7‘-bisacceptor-Substituted Fluorescent Derivatives

Pure 2,2‘-Dibromo-9,9‘-spirobifluorene was synthesized by a method that did not involve troublesome dibromination of 9,9‘-spirobifluorene or
Sandmeyer reaction of 2,2‘-diamino-9,9‘-spirobifluorene. A series of donor−acceptor orthogonally substituted 9,9‘-spirobifluorene was subsequently
prepared showing rich variation of fluorescence in solution and in solid state.