Study On The Recognition Function Of Coumarin-Modified Salamo-Like Chemosensors And Zn(?)and Co(?)Complexes

Heavy metal ion pollution will cause serious harm to the natural environment and organisms.Due to their excellent selectivity and fast response speed,fluorescent probes have become a powerful tool for detecting heavy metal ions in living bodies and the environment.Coumarin compounds have excellent optical properties and are widely used in the fields of fluorescent probes and colorimetric probes.In this paper,a coumarin-based salamo-like ligand H2L1 was designed and synthesized,and two novel 3d metal complexes of Zn? and Co? were obtained and characterized by relevant physical and chemical methods.In addition,three salamo chemical sensors H4L2,HL3 and H3L4 based on coumarin were designed andsynthesized,and their possible recognition mechanisms were discussed.Complex 1:chemical composition is C48H52N6O13Zn2,Mr=1051.69,belongs to the orthorhombic system,space group Pbca,unit cell parameters:a=17.86971(6)nm,b=14.8133(5)nm,c=36.2496(6)nm,?=90°,?=90°,?=90°,Z=8,V=9595.6(6)nm3,R1=0.0625(7211),wR2=0.1422(9920);complex 2:The chemical composition is C48H52Co2N6O13,Mr=1038.81,belongs to the orthorhombic system,space group Pbca,unit cell parameters:a=17.8736(5)nm,b=14.7661(4)nm,c=36.3681(14)nm,?=90°,?=90°,?=90°,Z=8,V=9598.4(5)nm3,R1=0.0670(5664),wR2=0.1891(8455).The coumarin-modified bissalamo-like sensor H4L2 was designed and synthesized,which can be used as a fluorescent probe to recognize Cr3+and Al3+,showing fluorescence quenching,and L-Cr3+system can ecognize S2-,Because S2-reacts with Cr3+to form insolubleCr2S3,Cr3+breaks away from the acceptor H4L2 and causes the fluorescence to turn on again.Through anti-interference experiments,it was found that in the presence of other metal ions,H4L2's recognition of Cr3+would not be interfered by other cations.The suitable recognition mechanism can be inferred from1HNHR and ESI-MS.Experimental research was found that the quenching constants of Cr3+and Al3+to the receptor H4L2 were 3.449×106M-1 and 2.406×106 M-1,respectively.Using the formulas LOD=3×?/S and LOQ=10×?/S,we calculated sensor H4L2 recognized Cr3+with LOD=4.87×10-7 M and LOQ=2.76×10-6 M.In addition,in practical application,S2-in different water samples was detected,and the recovery was good,indicating that the probe has practical application value.The coumarin-modified salamo-like sensor HL3 based on coumarin can continuously recognize Cr3+ and arginine,and the fluorescence was "on-off-on".When Cr3+was added,the fluorescence was quenched,and when Arg was added,the fluorescence On,the presence of other metal ions and amino acids will not interfere with the recognition of Cr3+and arginine by the probe,and it had high specificity and selectivity for HS-in the ultraviolet spectrum,and it possessed good competitive experiments.We calculated that the LOD for Cr3+of HL3 was 5.98×10-7 M and the LOQ was 3.36×10-6 M.In addition,the salamo-like chemosensor H3L4 can specifically identify Al3+,and it showed fluorescence quenching.The binding constant value was 2.45×106 M-1,the minimum detection limit was 6.64×10-7 M,and its recognition mechanism was determined by fluorescence titration and Job curve.