Size Effect of Arylenediimide π-Conjugate Systems on the Photoresponsive Behaviors in Eu<sup>3+</sup>-Based Coordination Polymers
Gao‐Peng Li, Hong‐Fang Xie, Pengfei Hao, Yunlong Fu, Kun Zhang, Junju Shen, Yao‐Yu Wang
Abstract
Various arylenediimides (ADIs) have been applied to construct photoresponsive coordination polymers (CPs), while the size effect of ADI π-conjugate systems on the photoresponsive behaviors in CPs has been overlooked in the past few years. Herein, we emphasize the size effect of ADI π-conjugate systems on photoinduced electron transfer (ET) in CPs, taking two Eu3+-based CPs, [Eu(H2BINDI)(BINDI)0.5(H2O)2]·NH2(CH3)2·8H2O (1) and [Eu2(BIPMDI)(DMF)4(NO3)2]·H2O·2DMF (2) [H4BINDI = N,N′-bis(5-isophthalic acid)naphthalenediimide; H4BIPMDI = N,N′-bis(5-isophthalic acid)pyromellitic diimide; DMF = N,N-dimethylformamide], as a case. Both 1 and 2 display ET-based photochromic behaviors with distinct photoresponsive rates and coloration contrast, which can contribute to the size effect of diimide cores on the interfacial contacts of electron donors/acceptors. Meanwhile, ET between the neighboring larger NDI cores of the H4BINDI ligands can block ligand-to-metal charge transfer and quench luminescence of the Eu3+ metal center in 1. Therefore, this work will provide a theoretical basis for the development and exploration of photoresponsive materials.