Research About Luminescence Switch Properties And Application Based On Platinum(?) Complexes With 4-Cl-2,2'-bipyridine As Auxiliary Ligands

Luminescence switching properties is a kind of changing progress between two steadystates upon external stimulus(such as high temperature,illumination,mechanical force,vapor,coordination and acid-base property)which leads to the change of color and(or)luminescence.As the properties of intuition,timeliness and selectivity,this material shows wide application value in sensor,anti-counterfeit,information storage and encryption,environmental monitor etc.In this paper,we designed and synthesized nine platinum complexes by using4-Cl-2,2'-bipyridine as main ligand and different benzene acetylene ligands as auxiliary ligands.Through fluorescence spectra,1HNMR,UV-vis spectra,IR spectra,X-ray single crystal diffraction,powder XRD spectra and so on,we deeply studied the structures and luminescence properties of these platinum complexes.We found that complex 4 had no response upom usual external stimulus.Complexes 5,6 and 9 only responsed to mechanical force,demonstrating mechanoluminescence.Meanwhile,complexes 7 and 8 showed two luminescence properties,including thermoluminescence and mechanoluminescence.Complexed 1,2 and 3 had three luminescence properties upon bearing mechanical force,vapor and heat.As research data shows,the mechanism of the properties are ascribed to the change of molecular stacking patterns by external stimulus,which leads to the change of intermolecular Pt-Pt interaction,hydrogen-bond interaction and ?-? stacking interaction,then leads to the change of the lowest excited states followed by the change of color and(or)luminescence.As complexes of Pt have the unique response upon external stimulus and it is easy to carry out,we raise to apply the complexes to anti-counterfeit.Its advantages are no assist-additive,dual-change and multiple responses which enable the high discriminability of these complexes when using as anti-counterfeit materials.This research is one new step both for the application area of luminescence switching Pt complexes and the chemical anti-counterfeit materials.