Unique fluorescence of boronic acid derived salicylidenehydrazone complexes with two perpendicular ICT: Solvent effect on PET process

Abstract Solvent effects on the absorption and emission spectra of organic compounds have been widely observed. It is usually found that the positions, intensities and shapes of its bands are usually modified by these solvents. The solvent effects on intramolecular charge transfer (ICT) process have been extensively reported, whereas the solvent effect on photoinduced electron transfer (PET) process is scarce. In this contribution, it was disclosed that boronic acid derived salicylidenehydrazone complexes (BSs), BS-DPE and BS-DPBDE, with two perpendicular ICT states developed a non-fluorescent PET compounds through separating its two ICT states by boron node. Relative strong acidic proton in non-hydrogen-bond accepting solvent were proved to actuate the vanishment of PET and reinstatement of its fluorescence.