Response Performances Of Macrocyclic Samarium Complexes For Metal Ions

Metal ions exist widely in nature,some of which are closely related to our daily production and life.At present,the high-efficient detection of metal ions is one of the most important research fields for chemistry,environmental science,biology,clinical diagnosis,medicine and so on.In the past decade,a variety of metal ion chemosensors have been designed and many excellent results have been reported.However,there are still some shortcomings in the multi-response of metal ions which needs to be improved by new chemosensors and more explorations.In this work,based on the template method,we have designed and synthesized three Schiff-base macrocyclic Sm(?)complexes,which possess the dynamic reversibility of imine bond and the sharp emission of Sm(?).Their optical response performances for various metal ions are carefully studied.As a result,it is shown that these complexes can serve as high-efficient chemosensors and achieve the multi-response for some metal ions in solution.Relative research contents are listed as follows:1.Firstly,to explore photophysical properties of our proposed Sm(?)complexes in different mixed solvents,a Schiff-base macrocyclic Sm(?)complex Sm-2_gwas designed and synthesized as a turn-off fluorescent and colorimetric probe for the detection of water content in organic solvents(DMF,methanol,acetone).Relative results show that the Sm-2_ghas the rapid and sensitive response for water which can be distinguished by obvious weakened fluorescence and shifted absorption.Finally,it is found that this probe had the widest response range for water in methanol which provides the critical foundation for subsequent studies of detecting metal ions.2.For four alkali metal ions,a macrocyclic mononuclear Sm(?)complex Sm-2_fwas designed and synthesized.As a colorimetric probe,Sm-2_fcan selectively and quickly recognize Li⁺in solution regardless of the presence of other alkali metal ions.Based on UV-Vis titration experiments,the detection limit of Li⁺is determined as 1.147 m M,and the response process can be completed within 60 seconds.In addition,this probe also successfully determines the Li⁺content in a psychotropic drug.3.A luminescent mononuclear Sm(?)complex Sm-2_hwas designed and synthesized to investigate its response performances for numerous alkali earth metals and transition metal ions.Relative results suggest that it has the extremely high selectivity for Zn²⁺and its response process is very fast.The detection limit of Zn²⁺is determined as 5.67 and 3.53?M by corresponding fluorescent and colorimetric titration experiments.In addition,probe Sm-2_hcan be not only directly used for determining Zn²⁺in real water samples but also made into paper-based sensors for the fast and convenient detection of Zn²⁺in more applications.