Size Effect of Arylenediimide ?-Conjugate Systems on the Photoresponsive Behaviors in Eu3+ -Based Coordination Polymers

Various arylenediimides (ADIs) have been applied to construct photoresponsive coordination polymers (CPs), while the sizeeffect of ADI pi-conjugate systems on the photoresponsive behaviors inCPs has been overlooked in the past few years. Herein, we emphasize thesize effect of ADI pi-conjugate systems on photoinduced electron transfer(ET) in CPs, taking two Eu3+-based CPs, [Eu(H2BINDI)-(BINDI)0.5(H2O)2]middotNH2(CH3)2middot8H2O(1)and[Eu2(BIPMDI)-(DMF)4(NO3)2]middotH2Omiddot2DMF (2)[H4BINDI =N,N '-bis(5-isophthalicacid)naphthalenediimide; H4BIPMDI =N,N '-bis(5-isophthalic acid)-pyromellitic diimide; DMF =N,N-dimethylformamide], as a case. Both1and2display ET-based photochromic behaviors with distinct photo-responsive rates and coloration contrast, which can contribute to the sizeeffect of diimide cores on the interfacial contacts of electron donors/acceptors. Meanwhile, ET between the neighboring larger NDI cores ofthe H4BINDI ligands can block ligand-to-metal charge transfer and quench luminescence of the Eu3+metal center in1. Therefore,this work will provide a theoretical basis for the development and exploration of photoresponsive materials.

Automated summary

This study emphasizes the size effect of arylenediimide (ADI) pi-conjugate systems on photoinduced electron transfer in photoresponsive coordination polymers (CPs). Two Eu3+-based CPs were used as examples to demonstrate that the size of the diimide cores can impact the interfacial contacts and luminescence properties.