Synthesis And Properties Of Fluorescent Chemodosimeters For Cu²⁺ Based On BODIPY

Copper, second only to iron and zinc, is the third-most-abundant among the essential transition metal ions in the human body and plays a critical role in physiological processes. However, the imbalance of the copper ion concentration would bring living organism a serious of diseases such as Parkinson’s disease, Menkes syndrome, Alzheimer’s disease, Wilson’s disease, familial amyotrophic lateral sclerosis and so on. Recently, many researchers have designed and successfully synthesized fluorescent probes for detecting copper ion, and what drew considerable attention in academia refers to the fluorescent probe based on chemical reaction mechanism. However, many of these are restricted from several aspects, for example, some might act only in pure organic solvents or solutions with very small amounts of water, and some are required with specific reaction conditions or show low Cu2+ selectivity in the presence of other metal ions. Thus, much great efforts are still needed to develop new fluorescent probes for Cu2+ with high selectivity and sensitivity.As a fluorescent dye, BODIP Y has the advantages of a high fluorescence quantum yield, good optical and chemical stability, high molar extinction coefficient, slightly affected by pH and so on. It is currently endowed with high frequency of being chosen by modern scholars.Here in this article presents a BODIPY-based compound:M1. In aqueous N,N-Dimethylformamide solution, the compound Mi can recognize Cu2+ without being interfered by common anions (NO3-, Br-, Cl-, SO42-, OAc-) or other metal ions (Zn2+, Cd2+, Pb2+, Cr3+, Mg2+, Ca2+, Ba2+, Mn2+, Hg2+, Sn2+, Li+, Na+, Bi2+, K+, Al3+, Fe3+, Co2+ Ni2+, Fe2+, Ag+) but with high sensitivity for Cu2+. Added with Cu2+ for a period, the colour of the M1 solution has a significant change and the fluorescence enhancement of M1 is ca. 75-fold. The detection limit of M1 to Cu2+ is 0.10 μM.M1 is a pH-insensitive Cu2+ probe, which could detect Cu2+ in a wide range of pH environment, especially for neutral pH ranging from 6 to 8. In addition, recognition mechanism of this kind of fluorescence probe toward Cu2+ has also been studied by 1H-NMR spectral titration and mass spectrum(MS), by which finally led to the mechanism that Cu2+ firstly coordinated with the probe molecule and then promoted the hydrolysis of unsaturated CH=N bond in the hydrazine molecule.