A Series of Highly Connected Metal–Organic Frameworks Based on Triangular Ligands and d¹⁰ Metals: Syntheses, Structures, Photoluminescence, and Photocatalysis

Four novel highly connected metal–organic frameworks (MOFs) based on d¹⁰ metals and triangular ligands, namely, [Ag₇(4,4′-tmbpt)­(HL)₂(L)­(H₂O)] (1), [NaCd₃(4,4′-tmbpt)­(L)₂(OH)]·H₂O (2), [Cd₃(3,3′-tmbpt)₂(L)₂(H₂O)₂]·3.5H₂O (3), and [Cd₃(3,4′-tmbpt)₂(L)₂(H₂O)]·1.5H₂O (4) (H₃L = 5-(4-carboxybenzyloxy)­isophthalic acid, 4,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)­methyl)-3,5-bis­(4-pyridyl)-1,2,4-triazole, 3,3′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)­methyl)-3,5-bis­(3-pyridyl)-1,2,4-triazole, and 3,4′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)­methyl)-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4-triazole) have been synthesized under hydrothermal conditions. Compound 1 features a three-dimensional (3D) (3,12)-connected net based on heptanuclear [Ag₇(COO)₇] units. Compound 2 displays a 3D (3,4,10)-connected net constructed by tetranuclear [NaCd₃(μ₃-OH)­(COO)₅]⁺ units. Compound 3 exhibits a 3D (3,4,8)-connected net based on binuclear [Cd₂(COO)₂] units. Compound 4 is a 3D binodal (3,9)-connected framework constructed by trinuclear [Cd₃(COO)₄] units. The diverse structures of compounds 1–4 indicate that the central metals and the N-donor ligands have significant effects on the final structures. The photoluminescent properties of compounds 1–4 have been studied in detail. Remarkably, compounds 1, 2, and 4 exhibit photocatalytic activities for degradation of dye under UV light irradiation and show good stabilities toward UV-light photocatalysis.