Fluorescent and Chemiluminescent Dyes with Aryl Phthalimide and Aryl Luminol Chromophores

Luminol is one of the most widely established and most well-known chemiluminescent molecules with diverse applications in modern analytical sciences such as forensics and cell assays. Structural and electronic modifications of the parent luminol can effectively enhance the (photo)physical and (photo)chemical properties. Herein, a straightforward route to stereoelectronically modulated luminol derivatives is developed by utilization of an effective cross-coupling at a versatile bromo phthalimide precursor. The modular synthesis enabled convenient access to two distinct classes of photoactive molecules: highly fluorescent 6–aryl–4–amino N-methyl phthalimides and chemiluminescent 7–aryl luminol derivatives. Electron-rich aryl substituents are shown to significantly enhance chemiluminescence (CL) quantum yields and exhibit good limits of detection in a CL hydrogen peroxide assay. The stereoelectronic effects on absorption, fluorescence, and CL properties are evaluated by experimental and theoretical studies.