Novel BODIPYs With Carboxyl Substituent On The Boron Center And BODIPYs Based NIR Fluorescent Probes: Design, Synthesis And Application

Boron dipyrromethene（BODIPY） as a fluorophore has tremendous superiority， such as highstability, big molar extinction coefficient, high fluorescence quantum yield, easily modified, sharpabsorption and fluorescence peaks have acted as good candidates for electro-luminescent films, biologicallabeling and fluorescent probes. Many detection means are applied to the research of modern biotechnologyand life sciences, because of good sensitivity, low detectability and good selectivity, fluorescence analysistechnology has played an irreplaceable role in the bioanalytical field. Herein a series of novel BODIPYswith carboxyl and four NIR fluorescent Probes based on BODIPY or Aza-BODIPY were designed andsynthesized. All compounds were characterized by1H NMR，13C NMR and HRMS. Their photo physicalproperties and responses to analytes were systematically investigated by means of UV-vis and fluorescencemethods.1、By one-pot reaction, twelve novel BODIPYs with carboxyl1-12were designed and synthesized.UV and fluorescence spectroscopic properties of12compounds were measured. The pH tolerance,photochemical stability, a water-soluble, electrochemical properties （cyclic voltammetry）, and a theoreticalcalculation of compounds1and7were measured. Compared with the parent BODIPY, compounds1and7have better light stability, water solubility and have potential applications in biological testing and targetedtherapy.2、An off-on NIR fluorescent probes BDT1was synthesized through introducing a aldehyde to8-position of BODIPY. Cysteine （Cys） and homocysteine （Hcy） were detected in solution （CH₃CN: H₂O=4:1） and their fluorescence intensity were enhanced9-fold and30-fold respectively. By different responserate, the two detection can be distincted.3、An off-on NIR fluorescent probes BDT2was synthesized through conjugating ethyl cyanoacetatewith8-aldehyde of BODIPY. H₂S was detected in solution （CH₃CN: H₂O=4:1）. When probe reactedwith HS-, the UV absorption blue-shifted from683nm to674nm, the fluorescent intensity increased60times.4、An on-off NIR fluorescent probes BDT3was synthesized through conjugating ethanethiol with8-aldehyde of BODIPY. Hg²⁺was detected in solution （CH₃CN: H₂O=4:1）. When probe reacted withHg²⁺, the UV absorption red-shifted from672nm to769nm, the fluorescence blue-shifted from690nm to668nm and the intensity decreased27times.5、An off-on NIR fluorescent probes BDT4was synthesized through conjugating2,4-dinitrophenylchloride with Aza-BODIPY. Thiols was detected in solution （CH₃CN: H₂O: DMSO=79:20:1）. Whenprobe reacted with Cysteine （Cys）, the UV absorption red-shifted from717nm to735nm, the fluorescencered-shifted from734nm to755nm and the intensity increased11times.