Syntheses and structures of tetranuclear Zn(Ⅱ) complexes with in situ generated macrocyclic Schiff base ligands:Applications in Zn^(2+) sensing

摘要

Three novel Zn（II） complexes,[Zn4L1Cl4]-3H2O（1）,[Zn4L2Cl4]-2DMF（2） and[Zn4L3Cl4]H2O（3）,have been synthesized and structurally characterized.In these complexes,interesting 32-membered dodecadentate macrocyclic ligands were generated in situ by ’2 + 2’ type condensation reactions between a tetraamine and various dialdehydes.All the complexes are isostructurally tetranuclear Zn（Ⅱ） complexes,containing endogenous alkoxo and phenoxo bridges.Applications of the macrocyclic ligands as Zn2+ sensors have been investigated.Take H4L1 for example,it exhibits a 4-fold fluorescence enhancement upon the addition of 2 equiv.of Zn2+ in MeOH.