A thermal stable pincer-MOF with high selective and sensitive nitro explosive TNP, metal ion Fe3+ and pH sensing in aqueous solution

A new 2D pincer-MOF [L4Cd3(H2O)(2)]n (1) (H2L = 1,3-(bis(6-(2-methyl)nicotinyl))benzene) was synthesized by solvothermal method. In complex 1, each ligand links adjacent [Cd(COO)(2)](n) chains to generate bi-layer 2D sheet. Emission spectrum reveals the fluorescence of complex 1 is mainly from the ligands to ligands charge transfer transition. Further investigation indicates that complex 1 can be employed as high selectively fluorescence sensor for detecting TNP and Fe3+ in aqueous solution, the quenching constant (K-sv) for TNP is 6.6 x 10(4) M-1 with the detection limit (LOD) of 0.119 mu M; the Ksv for Fe3+ is 9.8 x 10(4) M-1 with the LOD of 0.095 mu M. Besides, complex 1 has positive responses to pH values (pH = 2-3). Furthermore, the sensing mechanisms have been studied based on experiments and theoretical calculations.