Excitation Induced Emission Color Change Based on Eu(III)-Zn(II)-containing Polymer Complex

A novel polymer P-1 is prepared by the reaction of the monomer 5,5'-divinyl-2,2'-bipyridine and Salen-Zn(II) via Heck cross coupling. Interestingly, P-1 can further incorporate with Eu(TTA)3.2H2O to generate copolymer P-2 with two different metal centers. P-2 exhibits exceptional dual emissive properties which can be tuned by excitation wavelength. For example, an orange fluorescence can be obtained when P-2 is excited at 430 nm, whereas a red emission with a huge Stoke shift of 57 nm is observed when it is excited at 345 nm. The high wavelength emission can be attributed to Eu(III) (5D0?7F2), which is lit by an effective photoinduced energy transfer process between P-1 and the Eu(TTA)3 complex. The properties of P-2 have led to a better understanding of the energy transfer process between P-1 and Eu(TTA)3 moieties.