Two 3D metal organic frameworks as multi-functional materials to detect Fe3+ ions and nitroaromatic explosives and to encapsulate Ln3+ ions for white-light emission

Two metal-organic frameworks (MOFs), namely {[Zn-3(L)(2)(4,4'-bipy)(DMF)(2)]center dot 2H(2)O}(n) (1) and {[Cd-3(L)(2)(4,4'-bipy)(H2O)(2)]center dot 2DMF}(n) (2) (4,4'-bipy = 4,4'-bipyridine, DMF = N,N-dimethylformamide), were solvothermally prepared based on a rigid tricarboxylic acid 3-(3,5-dicarboxylpheny1)-5-(3-carboxylpheny1)-1-H-1,2,4-triazole (H3L). X-ray crystallographic analysis reveals that 1 and 2 are isostructural and both emit blue light. Notably, 1 exhibits good luminescent sensing for nitro-containing compounds and Fe3+ ions. In addition, the emission colors of 1 can be tuned from yellow to white and to blue by encapsulating different mole ratios of Eu3+ and Tb3+ ions and changing the excitation wavelength. A white emission with the Commission International de l'Eclairage (CIE) coordinates of (0.331, 0.337), which fall within the white-light region, emerges upon excitation at 340 nm.