Lead–Organic Frameworks Containing Trimesic Acid: Facile Dissolution–Crystallization and Near-White Light Emission

Three new, closely similar Pb-based organic frameworks synthesized using a simple and optimized dissolution–crystallization method with benzene-1,3,5-tricarboxylic acid (H₃BTC) are reported along with their structural characterizations and photoluminescent properties. Compound 1, Pb­(HBTC)­(1,4-dioxane)_0.5, crystallizes in the C2/c space group (a = 17.239(2) Å, b = 7.0225(8) Å, c = 19.911(2) Å, β = 104.735(10)°); compound 2, Pb₂(HBTC)₂­(H₂O)₅, crystallizes in the P1̅ space group (a = 7.3989(4) Å, b = 8.2196(4) Å, c = 10.1437(5) Å, α = 94.336(4)°, β = 104.943(4)°, γ = 108.270(3)°); and compound 3, Pb­(HBTC)­(DMF), crystallizes in the P2₁/n space group (a = 10.5004(3) Å, b = 7.1398(3) Å, c = 17.1285(5) Å, β = 102.160(2)°). All three compounds are built from a slightly different one-dimensional (1D) structure interconnected into three-dimensional metal–organic frameworks by HBTC^– ligands forming different pore sizes, in which the 1D moieties and pore sizes are governed by the solvent used during synthesis. Among the three compounds, compounds 1 and 2 exhibit solid state photoluminescence with 2 showcasing an interesting, near white-light emission, single-component phosphor with CIE coordinates of (0.33, 0.36).