Boron Dipyrromethene (BODIPY) Based Fluorescent Probes For Metal Ion: Design, Synthesis And Application

Fluorescent probes can transfer molecular recognition events into fluorescence signals and then make a bridge between man and molecule. The advantages of molecular fluorescence for sensing can be summarized:high sensitivity of detection down to the single molecule, "on-off”switch ability, subnanometer spatial resolution and submillisecond temporal resolution, observation in situ, remote sensing by using optical fibres, etc. Off-On fluorescent probes have tremendous superiority. They have low autofluorescence and show good sensitivity.Boron dipyrromethene (BODIPY) as a fluorophore has tremendous superiority, such as big molar extinction coefficient, sharp absorption and fluorescence peaks, high fluorescence quantum yield and high stability. Herein five fluorescent probes based on BODIPY for ions were designed and synthesized. All compounds were characterized by 1HNMR,13C NMR and HRMS. Their photophysical properties and responses to cations were systematically investigated by means of UV-vis and fluorescence methods.1. Fluorescent probe (CS1) was designed and synthesized, whose receptor of polyamide was conjugated to 3-position of BODIPY through styryl. The probe could detect Cd2+ selectively and sensitively in neutral buffer solution. The fluorescent intensity enhanced about 200-fold and fluorescence quantum yield increased almost 100-fold after Cd2+addition. Moreover, its fluorescence intensity enhanced in a linear fashion with concentration of Cd2+ and thus can be potentially used for quantification of Cd2+. CS1 can readily distinguish Cd2+ from Zn2+by both naked eye and fluorescence, and the living cell image experiments further demonstrate its value in the practical applications of biological systems.2. Another fluorescent probe of CS2 for cadmium was synthesized through conjugating two polyamide receptors to 3-and 5-position of BODIPY. It is a selective off-on probe for Cd2+in aqueous solution. The complex CS2-Cd of CS2 with Cd2+showed good selectivity and sensitivity toward pyrophosphate (PPi). The fluorescent intensity of CS2-Cd decreased significantly with PPi addition, and it could distinguish PPi from ADP and ATP.3. NIR probe HMS (λem= 658nm) was designed and synthesized, which introduced two different substituent groups to 3-and 5-position of BODIPY. The selectivity of HMS toward Cd2+, Hg2+and Pb2+could be modulated via judicious choice of aqueous buffer solutions.4. A hypochlorite probe HCS based on BODIPY and hydrazinium was synthesized. When C10- was added, obvious absorption wavelength change was observed and the fluorescence decreased significantly with wavelength blue-shift.