Synthesis And Properties Of New Amphiphilic Aza-BODIPY NIR Dyes

In recent years,near-infrared fluorescent dyes have become the research hotspot because of their excellent performance in biological imaging and photothermal therapy.Aza-BODIPY dyes are widely used in many fields due to their long wavelength absorption,high molar absorption coefficient,modifiable structure and high stability.On the other hand,aggregates based on BF₂-azadipyrromethene molecules with modifiable structure exhibit different characteristics and functions,which enable their application value compared with the monomer molecules.In this work,p-aminobenzaldehyde,bromopropyne,p-aminoacetophenone and bromododecane are used as raw materials,and two new amphiphilic aza-BODIPY dye are synthesized by introducing N,N dipropargyl groups at the 3,5-phenyl of the aza-BODIPY core through“click”reaction.Their yield are 72%-81%.The chemical structures are characterized by ¹H NMR,¹³C NMR,elemental analysis and high-resolution mass spectrometry(HRMS).The basic optical properties,self-assemble properties and related applications were studied through transmission electron microscopy,UV-Vis absorption spectroscopy and fluorescence emission spectroscopy.The results show that the absorption of the two dyes are at?_abs=786-788 nm,the maximum emission are at?_em=838–841 nm,which have high molar absorption coefficient(1.3×10⁵M^-1cm^-1)and fluorescence quantum yield(0.21).The properties and electrochemical properties of dyes solution in different polarities are researched by spectroscopy and voltammetry,the results indicate that compounds 1 and 2 are environmentally sensitive dyes,and electron transfer between the donor and acceptor in the molecules can occur spontaneously.And the ion recognition test provides an evidence that dye 1 has selective recognition for Cu²⁺.In addition,the aza-BODIPY 1 and 2 have high photothermal conversion efficiency according to the photothermal heating curves.Subsequently,we also conducted a preliminary exploration of the self-assembly performance mechanism of dye 2 in methanol.