Four metal-organic frameworks for the sensing of oxytetracycline/nitrofurazone and Fe3+ ions

Four new d10 metal-organic frameworks (MOFs), named {[Cd(L)(TPA)]}n (1), {[Zn3(L)(BTC)2]}n (2), {[Zn(L)(1,4-NDC)]·2H2O}n (3), and {[Cd(L)(1,4-NDC)]·1.5H2O}n (4) (L = 1,6-bis(1-(pyridine-4-ylmethyl)-1H-benzo[d]imidazole-2-yl)hexane, H2TPA = terephthalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid, 1,4-H2NDC = 1,4-naphthalene dicarboxylic acid), are successfully synthesized by hydrothermal method and further characterized. 1 can be simplified into a dia framework, an unusual 4-nodal 3,4,4,6-topology of 2 was deposited into the TopCryst database as cgh8, 3–4 are simplified to 2D sql networks. 1–4 exhibit chemical stability, which are stable in a wide pH range from 3 to 12. The sensing of the oxytetracycline/nitrofurazone and Fe3+ ions display the selectivity, sensitivity, and reusability of 1‒4. Moreover, the mechanism of luminescence quenching is also investigated as photo-induced electron transfer and Förster resonance energy transfer.