The Synthesis,structures And Properties Of Fluorescence Coordination Compounds Based On The Sulfhydryl N-heteroatom Ligands

The controllable synthesis of functional coordination compounds is still a challenge in the crystal engineering.In this paper,the fluorescence compounds were constructed based on selected metal ions and ligands.The sulfhydryl N-heteroatom ligand contains two different coordination atoms of nitrogen and sulfur.There are many different coordination modes and the tautomers of thiol and thione in solution.In this paper,five complexes with novel structures and excellent performance were synthesized based on sulfhydryl N-heteroatom ligands and metal ions such as silver and copper under solvothermal conditions.The properties and structure of the compounds were studied.The main experiment process and result analysis are as follows:1.Three complexes with Cu₆S₆ cluster based on 4,6-dimethyl-2-mercaptopyrimidine?Hdmpymt?and 2-mercaptopyrimidine?Hpymt?have been synthesized,namely:{[?Cu₂I₂?[Cu₆?dmpymt?₆]}_n?1?,[Cu₆?dmpymt?₆·H₂O]?2?,[Cu₆?pymt?₆]?3?.Complexes 2 and 3are both composed of nitrogen and sulfur to form a Cu₆S₆ cluster.Compound 1 was synthesized under solvothermal condition and determined to be composed of Cu₆S₆ and Cu₂I₂binary Cu?I?clusters.1 demonstrated good stability in water and some organic solvents and displayed apparently red luminescence.The fluorescence decay time of 1 is 0.89?s and the absolute quantum yield is 6%.The emission band of 1 may be attributed to ligand-to-metal charge transfer?LMCT?and d-s transitions?the d-s transition is due to the short Cu-Cu interactions within Cu₆S₆ and Cu₂I₂ units?.The fluorescence intensity of 1 and 3 in different organic solvents was tested and it was found that nitrobenzene had a quenching effect on 1.The fluorescence spectrum of 1 in different metal ions or anion solutions shows that 1 exhibits fluorescence quenching for CrO₄^2-,Cr₂O₇^2-and Fe³⁺,and the quenching effect is not disturbed under the existence of other ions.The K_SV values of the quenching efficiency constants for CrO₄^2-,Cr₂O₇^2-and Fe³⁺are 1.06×10³ M^-1,1.90×10³ M^-1 and 8.73×10² M^-1,respectively.Fluorescence experiments illustrated that 1 displayed efficiently naked eye colorimetric sensing for nitrobenzene?NB?,CrO₄^2-,Cr₂O₇^2-and Fe³⁺by fluorescence quenching in the emulsions.Through the exploration of the reaction conditions,it was found that4,6-dimethyl-2-mercaptopyrimidine?Hdmpymt?and copper,silver can emit a significant fluorescence under grinding conditions with the aid of ethylenediamine and acetonitrile.The effect of organic amines on the fluorescence performance during mechanical grinding was discussed.2.A compound with Ag₆S₆ cluster based on 4,6-dimethyl-2-mercaptopyrimidine?Hdmpymt?has been successfully synthesized under solvothermal conditions,namely:[Ag₆?dmpymt?₆]?4?.The obvious green fluorescence emission of compound 4 can be observed under ultraviolet light.When the excitation wavelength is 369 nm,4 has the maximum emission at 515 nm,the fluorescence decay time is 5.59?s,and the absolute quantum yield is49.98%.The fluorescence emission is attributed to the Ag-Ag interaction within the Ag₆cluster and ligand-metal charge transfer?LMCT?.It was found that the fluorescence quenching of 4 was highly selective and sensitive to NB,Fe?III?and Cr?VI?and the detection limits of NB,CrO₄^2-,Cr₂O₇^2-,and Fe³⁺were 1.66×10^-6 M,1.25×10^-6 M,1.33×10^-6 M,and7.26×10^-7 M,respectively.It can also be used as a fluorescent probe for detecting organic small molecules,metal ions or anions.During the experiment,the fluorescence of the material was simply regulated by the calculation of CIE chromaticity coordinates of 1 and 4.3.A compound based on 1-?4-Hydroxyphenyl?-5-mercaptotetrazole?HOPMTZ?has been synthesized in situ,namely:[Cu₂I?dmtrz?]_n?5??Hdmtrz=3,5-dimethyl-1-H-1,2,4-triazole?.Compound 5 is formed by dimethyltriazole formed in situ and CuI to form a 3D framework.Fluorescence analysis revealed that complex 5 has a distinct yellow fluorescence emission.The emission band of 5 may be attributed to Cu-Cu interactions within the compound and halogen-to-metal charge transfer?XMCT?.The compound has potential applications in the field of photoelectric materials.