4-Amino-1,8-naphthalimide Based Fluorescent Probes For ROS: Design, Synthesis And Property

In the work, two different fluorescent turn-on probes (FS, Cu2+[FL]), based on 4-amino-1,8-naphthalimide chromophore, were designed and synthesized successfully. All the compounds were characterized by'H NMR, 13C NMR and HRMS. Their photophysical properties and responses to various ROS were investigated by means of UV-Vis and fluorescent methods systematically.1. A new o-phenylenediamine-based fluorescent molecule FS was synthesized as chromogenic and fluorogenic NO probe using Cu2+ as a promoter. The Cu2+[FS] generated through combining FS with Cu2+ exhibited a significant fluorescent increase and a large blue shift of 200 nm upon addition of nitric oxide in neutral buffer solution. The fluorescence response toward nitric oxide is highly selective and sensitive over other biologically ROS and RNS. The analytical detection limit (ADL) was 30 nM. It is a novel copper-promoted nitric oxide fluorescent probe based on the o-phenylenediamine and opens up new possibilities for the construction of colorimetric and fluorescent sensor for nitric oxide.2. Copper complex-based probe Cu2+ [FL] was designed and synthesized through combining compound FL with Cu2+. The probe showed weak fluorescence due to the paramagnetic quenching from Cu2+. AAPH (2,2'-azobis-2-methyl-propanimidamide, dihydrochloride) is a water-soluble azo compound which is used extensively as peroxyl radical (ROO) generator. The probe Cu2+[FL] demonstrated a 46 nm blue-shift in absorption (from 514 nm to 468 nm) with a large colorimetric response and an off-on fluorescent response upon addition of AAPH (ROO) in neutral buffer solution. The fluorescence response toward ROO is selective and sensitive over other biologically ROS and RNS. To the best of our knowledge, this is the first copper complex fluorescent probe for peroxyl radical(ROO).