Study Of BODIPY Fluorescent Probes For PH And Metal Ions

With the rapid development of the life sciences,many ways of biomarks emerged as the times required.Molecular fluorescent probe is an important way,which is a necessary detection mean in research of modern biotechnology and life sciences,and is widely used in recognizing and detecting the materials of organisms(such as protein,DNA,metal ion,anion, proton and neutral molecular et at).The performance of the biomark is straightly subjected to the performance on the fluorescent dyes.The boron dipyrromethene(BODIPY)dyes have excellent photophysics and photochemistry properties such as high molar extinction coefficient,high stability against light and chemical reactions,and high fluorescence quantum yields,etc.Therefore,the studies on fluorescence molecular probes based on BODIPY dyes are attracting many people's attentions.pH fluorescent probes PS1-PS5 based on BODIPY dyes have been designed and synthesized.PS1(pK_a=7.71)and PS2(pK_a=7.11)among them are the near-neutral pH fluorescent probes,PS3(pK_a=5.03)could be used in detecting the acidic vesicle,and PS4 (pK_a=2.89)and PS5(pK_a=2.31)may be prepared to detect the cell with lower pH.The probes show excellent sensitivity and selectivity to pH,and the fluorescence spectrum is reversible. At the same time,it was found that the increase of aliphatic chain length and the introduction of aromatic group on the nitrogen atom linked methene at site 8 of BODIPY dyes can reduce the pK_a of them.It is the main reason that the affinity of a proton to this nitrogen atom becomes quite difficult owing to greater steric restriction.It is a new method for the design of this kind of pH fluorescent probes by changing the various substitutes on the nitrogen atom linked methene at site 8 of BODIPY.Compounds MS1,ZS1 and CS1 based on the principle of PET have been designed and synthesized,which display fine selectivity to Hg²⁺,Zn²⁺and Cd²⁺in water or organic media respectively.MS1 displays specific identification to the Hg²⁺in water media without the infection of other metal ions.ZS1 shows fine selectivity to Zn²⁺in water media;CS1 shows fine selectivity to Cd²⁺,and it is significant that CS1 could separate the Cd²⁺from Zn²⁺.