Lanthanide–Organic Frameworks Constructed from 2,7-Naphthalenedisulfonate and 1H-Imidazo[4,5-f][1,10]-phenanthroline: Synthesis, Structure, and Luminescence with Near-Visible Light Excitation and Magnetic Properties

Abstract

New Ln-metal–organic frameworks (Ln-MOFs), {[Ln­(2,7-NDS)­(IP)­(OH)­(H2O)2]·mH2O} n [Ln = Sm 1, Eu 2, Gd 3, Tb 4, Dy 5, m = 0.5–0; 2,7-NDS = 2,7-naphthalenedisulfonate, and IP = 1H-imidazo­[4,5-f]­[1,10]-phenanthroline) were obtained by the hydrothermal method. The Ln-MOFs feature one-dimensional double chain structures. The photoluminescent properties of these complexes were investigated. Notably, the Eu-MOF exhibits a broad excitation band from 250 to 400 nm in the UV–vis region, and it presents red emission from the 5D0 → 7F J transitions (where J = 0–4) of the Eu3+ ion. It is noteworthy that it still shows intense emission under near-visible irradiation at 350 nm < λex < 385 nm. Using the Eu-MOF as a luminescent sensor, the detection of Fe3+/Ag+ and ornidazole (ODZ)/ronidazole (RDZ) in aqueous medium was realized with long excitation wavelengths of 368 nm or even 385 nm in the near-visible region. This work provides a new approach to designing an efficient red emission with broad-band and near-visible light excitation and with luminescent chemosensor capability for biological applications. In addition, the Eu-MOF red light incorporated Gd-MOF blue-green light, and a white-light emission is realized based on a two-component Gd0.99803Eu0.00197 doped complex. Magnetic studies of the Dy-MOF reveal that it has a single-molecule magnet and slow magnetic relaxation behavior with an energy barrier U eff of 82.39 K.

A 2D cadmium metal–organic framework: Synthesis, structure and luminescence sensing for chromate, permanganate, cupric, silver and ferric

“…The sensing abilities of 1•4H 2 O•DMAC for Cu 2+ , Ag + and Fe 3+ are comparable with these of the documented MOFs. [ 9–11,13–15,21–23,25,28,31,32 ] For example, {[Zn 5 (L) 2 (DMF) 2 (H 2 O) 2 ]·2DMF} (H 5 L = 3,5‐di(3′,5′‐dicarboxylphenyl)benzoic acid) exhibited the K sv of 1.10 × 10 3 M −1 , 2.24 × 10 3 M −1 and 4.49 × 10 4 M −1 for Cu 2+ , Ag + and Fe 3+ , and the detection limit of 1.01 ppm, 0.64 ppm and 1.30 ppm for Cu 2+ , Ag + and Fe 3+ . [ 9 ] {[Eu(2,7‐NDS)(IP)(OH)(H 2 O)]·mH 2 O} n (2,7‐NDS = 2,7‐naphthalenedisulfonate, IP = 1H‐imidazo[4,5‐f][1,10]‐phenanthroline) showed the high K sv of 1.19 × 10 5 M −1 and 1.18 × 10 5 M −1 for Fe 3+ and Ag + , and the detection limit of 0.277 μM and 0.272 μM for Fe 3+ and Ag + .…”

“…[ 9 ] {[Eu(2,7‐NDS)(IP)(OH)(H 2 O)]·mH 2 O} n (2,7‐NDS = 2,7‐naphthalenedisulfonate, IP = 1H‐imidazo[4,5‐f][1,10]‐phenanthroline) showed the high K sv of 1.19 × 10 5 M −1 and 1.18 × 10 5 M −1 for Fe 3+ and Ag + , and the detection limit of 0.277 μM and 0.272 μM for Fe 3+ and Ag + . [ 13 ] {[Cd(L)(BPDC)]·2H 2 O} n and {[Cd(L)(SDBA)(H 2 O)]·0.5H 2 O} n [L = 4,4′‐ (2,5‐bis (methylthio)‐1,4‐phenylene)dipyridine, H 2 BPDC = 4,4′‐biphenyldicarboxylic acid, H 2 SDBA = 4,4′‐sulfonyldibenzoic acid] showed the K sv of 3.63 × 10 4 M −1 and 3.59 × 10 4 M −1 for Fe 3+ , the detection limit of 2.21 μM and 7.14 μM, respectively. [ 21 ] {[Cd (ATA)(L)]} n ·xH 2 O (H 2 ATA = 2‐aminoterephthalic acid, L = ( E )‐ N′ ‐(pyridin‐4‐ ylmethylene)isonicotinohydrazide) presented the K sv of 3.838 × 10 3 M −1 , and the detection limit of 1.77 μM for Fe 3+ .…”

“…Therefore, the quenching mechanism of 1•4H 2 O•DMAC for Cr 2 O 7 2− , CrO 4 2− , MnO 4 − and Fe 3+ can be assumed to the energy‐transfer. [ 9–15,21–30 ] However, no overlap between the UV–visible absorption spectra of Cu 2+ , Ag + and other ions with the excitation and emission spectra of 1•4H 2 O•DMAC . N1s X‐ray photoelectron spectroscopy (XPS) studies showed that the N1s peaks from triazole nitrogen atoms in 1•4H 2 O•DMAC were at 399.8, 401.8 and 405.2 eV (Figure 13).…”

“…In the past decade, the luminescence sensors based on metal–organic frameworks have been developed for the detection of metal ions such as Fe 3+ and Ag + , inorganic anions, volatile organic molecules, and explosives. [ 9–20 ]…”

Self-assembly of a cobalt(II)-based metal–organic framework as an effective water-splitting heterogeneous catalyst for light-driven hydrogen production

“…Metal-organic frameworks (MOFs), as a kind of porous materials, have been the subject of much research, not only owing to their high porosity and the high surface area of the structures which makes them useful for potential applications in gas storage and separation (Lorzing et al, 2019;Wang et al, 2019b), drug delivery (Orellana-Tavra et al, 2020) and molecular recognition (Zhu et al, 2017;Mizutani et al, 2020), but also for the tunability and tailorability of their coordination modes and the numerous possible modifications with functional groups making them useful in catalysis (Zhou et al, 2016;Ji et al, 2019;Song et al, 2019;Feng et al, 2019;Wu et al, 2019), fluorescent sensing (Mi et al, 2019;Yang et al, 2019c;Pratik & Cramer, 2019) and magnetic materials (Lan et al, 2019;Gu et al, 2018;Li et al, 2019). The self-assembly of MOFs with various organic linkers and metal ions or clusters endows these materials with active sites and designable backbones, displaying the combined advantages of homogeneous and heterogeneous properties as catalysts, such as high activity and selectivity on one hand, and recovery and high controllability on the other hand.…”