Design, Synthesis And Recognition Performance Of Near Infrared Fluorescent Probes Based On Cyanine Skeleton

Fluorescence imaging technology is an important method to identify small molecules.The fluorescent probes based on cyanine structure have excellent properties,such as low cytotoxicity,fluorescence emission wavelength in the near-infrared region,high quantum yields,high sensitivity and so on,which show very potent application in the future.We have designed the near-infrared?NIR?fluorescent probes based on the cyanine structure to achieve qualitative and detection of small molecules.1.A novel hemicyanine-based near-infrared fluorescence probe CY1OH2S for Hg²⁺detection was synthesized,which selectively and sensitively responds to Hg²⁺based on the Hg²⁺-promoted deprotection of thioacetal.This probe exhibited fast response,high sensitivity,and anti-interference performance for Hg²⁺based on the fluorescence enhancement in the NIR region in HEPES buffer(0.01 mol·L^-1,pH=7.40)solution.The detection limit of the probe for Hg²⁺was as low as 0.32?M.Probe-coated test paper was fabricated as a“naked-eye”indicator for Hg²⁺ions in water samples.In addition,the probe CY1OH2S exhibited good cell permeability and could be applied for monitoring the fluctuation of Hg²⁺in living HeLa cells and zebrafishes by NIR fluorescence imaging.2.Hypochlorite plays a significant role in various physiological and pathological processes.A novel-visible near-infrared fluorescent probe CY1OHCHO for ratiometric detection of hypochlorite has been synthesized and demonstrated that it could selectively and sensitively react with hypochlorite anion?ClO^-?.The NIR fluorescence probe CY1OHCHO showed very fast response,high sensitivity and anti-interference performance for ClO^-and has been successfully applied for the detection of ClO^-in PBS/CH₃CN buffer?0.01 M,v/v=9/1,pH 7.4?and it exhibited a rapid color change from blue to colorless.The detection limit was calculated as low as 0.53?M.It has been further demonstrated that the probe exhibited ideal cell permeability and could be applied for monitoring the fluctuation of ClO^-in HeLa cells by NIR fluorescence imaging.3.Harmful metal ions have received intense attention.In particular,palladium,a rare inner transition metal,is the subject of intense research in light of its catalytic capabilities and the restrictions on the levels of residual harmful metal ions in end products,has attracted wide spread interest from chemists.A near-infrared Pd²⁺probe Cy202 has been synthesized that exhibits pronounced fluorescence enhancement in the presence of Pd²⁺.The Pd²⁺recognition properties were examined by using UV-Vis and fluorescence spectroscopy in DMSO/PBS buffer solution?pH 7.40,8/2,v/v?.The detection limit of the probe for Pd²⁺was as low as 0.52?M.The solution of the probe Cy202 exhibits color change turned from yellow to brown upon the addition of Pd²⁺while no significant response to other metal ions.The probe could be useful for imaging Pd²⁺in palladium-containing catalyst and samples.