Photophysical Properties and Heterogeneous Photoredox Catalytic Activities of Ru(bpy)₃@InBTB Metal–Organic Framework (MOF)

Abstract

Metal-organic frameworks (MOFs) with negatively charged frameworks are suitable for selectively encapsulating cationic guest ions via ac ation-exchange process. Encapsulating photoactive [RuL 3 ] 2 + polypyridine complexes into the preorganized mesoscale channels of a MOF is ag ood methodf or stabilizing the excited states of the complexes. Three new RuL 3 @InBTB MOFs were prepared by encapsulating cationic [Ru(bpy) 3 ] 2 + (bpy = 2,2'bipyridine), [Ru(phen) 3 ] 2 + (phen = 1,10-phenanthroline), and [Ru(bpz) 3 ] 2 + (bpz = 2,2'-bipyrazine) into the mesopores of at hree-dimensional (3D) InBTB MOF (H 3 BTB = 1,3,5-benzenetribenzoic acid). The photophysical properties of the resultingm aterials were investigated by photoluminescence (PL) analysis. The photoredox catalytic activities were also investigated for the aza-Henry reaction,h ydrogenation of dimethyl maleate, and decomposition of methylo rangeu nder visible light irradiation at room temperature. RuL 3 @InBTB MOFs were found to be very stable and highly recyclable photoredox catalytic systems.

Photophysical Properties and Electrochromism of Viologen Encapsulated Viologen@InBTB Metal–Organic Framework

“…The low crystallinity of viologen@InBTB can be explained by the fact that DEF and water solvate molecules of InBTB can be partially exchanged with EtOH solvent as previously observed for dye@InBTB and RuL 3 @InBTB (L = polypyridine ligands). 17,22 The microscopic images of crystals did not show any signatures of change in crystal morphology as shown in Supporting Information Figure S2. Therefore, we speculate that the metal-ligand connectivity was maintained despite the partial loss of single crystallinity.…”

“…Nonetheless, the encapsulation amount was greater than that of Ru(bpy) 3 @InBTB, for which the encapsulation amount of divalent [Ru(bpy) 3 ] 2+ ion was 1.18 mmol/mmol-InBTB. 22 Notably, all viologen@InBTB retrieved by filtration after 5 days of encapsulation experiment displayed crystals with a change in color as depicted in Figure 1(b) and Figure S2 of the Supporting Information. They showed yellow crystals compared to the colorless as-prepared InBTB.…”

“…Our previous investigations firmly indicated that partial exchange of guest cations with [Et 2 NH 2 ] + counter-cations in as-prepared InBTB was quite successful for various guest ions. 16,17,22 Very large RD and a series of cationic Ru(II) polypyridine complexes such as [Ru(bpy) 3 ] 2+ (bpy = 2,2 0 -bipyridine) were encapsulated without any problems due to the sufficiently large mesoscale channels of InBTB. 16,22 Herein, viologen encapsulated MV@InBTB, EV@InBTB, and BV@InBTB MOFs were similarly prepared and characterized by various spectroscopic techniques.…”

Redox-Hopping-Based Charge Transport Mediated by Ru(II)-Polypyridyl Species Immobilized in a Mesoporous Metal-Organic Framework

“…(bpy = 2,2′-bipyridine), have received wide attention in the synthesis of the MOFs (Larsen and Wojtas, 2012;Lin et al, 2017;Choi et al, 2020;Yan et al, 2020;Stanley et al, 2021), both as a linker and as a non-structural ligand, due to their rich photophysical and electrochemical properties. Previously, our group reported the post-synthesis modification of hexazirconium nodes of mesoporous MOF NU-1000 by Ru II (bpy) 2 (dcbpy), i.e., bis-(2,2′-bipyridine)-(4,4′-dicarboxy-2,2′-bipyridine) ruthenium(II), and investigated the heterogeneous photocatalytic activity for an oxidative aminecoupling reaction (Nagatomi et al, 2020).…”

Performances of Homogeneous and Heterogenized Methylene Blue on Silica Under Red Light in Batch and Continuous Flow Photochemical Reactors

“…To counter such sustainability issues, our group and others have developed recyclable photocatalytic systems, such as heterogenized solid PCs (Mori et al, 2010;Mori and Yamashita, 2016;Tambosco et al, 2018;Choi et al, 2020;Gisbertz and Pieber, 2020;Soria-Castro et al, 2020;Materna and Hammarström, 2021). In particular, we investigated the straightforward non-covalent immobilization of PCs on silica particles which resulted in an improved reactivity and stability (Tambosco et al, 2018), and provided additional physical properties such as magnetism (Terra et al, 2020) or plasmonic resonance (Gellé et al, 2021).…”