Three Cd-MOFs with water stability act as novel fluorescent probes for detecting nitrofuran, nitrofurantoin and Fe3+

Three new metal-organic frameworks (MOFs): [Cd3(NTB)2(DPE)]·H2O (CUST-555), [Cd3(NTB)2(BIMB)]·H2O (CUST-556) and Cd3O(NTB)2(DPE) (CUST-557), (H3NTB ​= ​4,4ˊ,4ˊˊ-nitrilotrisbenzoic acid; DPE ​= ​1,3-di(4-pyridyl)ethane; BIMB ​= ​1,4-bis((1H-imidazole-1-yl)methyl)benzene), were obtained by solvothermal method. Single-crystal X-ray diffraction analyses revealed that CUST-555 and CUST-556 both crystallized in the monoclinic system with C2/c space group, while CUST-557 was in the trigonal system with P31 space group. The topological analysis showed that CUST-555 and CUST-556 had the same topology and were based on 3,8-connected net with the point symbol {43·624·8}{43}2, while CUST-557 was based on 3,8-connected net with the point symbol {43}2{46·618·84}. Luminescence studies show that CUST-555, CUST-556 and CUST-557 display highly sensitive, selective, and recyclable properties in the detection of ferric ion and nitrofuran antibiotics such as nitrofurantoin (NFT) and nitrofurazone (NZF). In addition, the possible fluorescence quenching mechanism were explored.