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

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.

Solvent-Modulated Self-Assembly of Naphthalenediimide-Based Cd(II) Complexes and the Controllable Photochromism via Conformational Isomerization

“…The binding energies of N 1s are 400.02 and 402.07 eV before visible light irradiation and 399.27 and 401.22 eV after radiation, which indicates that the N atoms get electrons. 48 The total signal of O 1s binding energy after photochromic was 0.58 eV higher than that of the unirradiated sample (531.17 eV for 2 and 531.75 eV for 2-P), indicating that the O atom lost electrons. 49 As a conclusion, the [NDI] −• radical that results from the ET interaction between the N atom of the NDI ligands and the O atom of the carboxylic acid should be the source of the photochromic behavior of 2.…”

“…The core energy-level spectra of C 1s and Cd 3d were almost unchanged before and after visible light irradiation, while the O 1s and N 1s of 2 changed significantly (Figure S10). The binding energies of N 1s are 400.02 and 402.07 eV before visible light irradiation and 399.27 and 401.22 eV after radiation, which indicates that the N atoms get electrons . The total signal of O 1s binding energy after photochromic was 0.58 eV higher than that of the unirradiated sample (531.17 eV for 2 and 531.75 eV for 2-P ), indicating that the O atom lost electrons .…”

A series of naphthalenediimide-based metal–organic frameworks: synthesis, photochromism and inkless and erasable printing

“…2). 29–31 Therefore, the photochromic mechanism can be attributed to photo-induced electron transfer. It is worth noting that irradiated solid H 4 BINDI also exhibits colour change from yellow to brownish yellow, and shows the similar radical signal ( g = 2.0025), indicating the presence of NDI˙ (Fig.…”

Construction of multi-hydroxyl/ketone lanthanide metal–organic frameworks for understanding mechanochromic luminescence and high proton conductivity

“…Because of the surprising emission changes the behavior of LnMOFs in response to different stimuli and the relevance of the [Zr 16 -Eu] and [Zr 16 -BPDC-Eu] structures, the luminescence of both types of LnMOFs under mechanical force stimulation was investigated. 27,28 First we studied the luminescence behavior of [Zr 16 -Ln] and [Zr 16 -BPDC-Ln] (Ln = Eu or Tb). The emission of both compounds gradually becomes weaker with the increase of grinding time as shown in Fig.…”