Cd-MOFs constructed from carboxyl-decorated tetrapoda ligands feature remarkable stability and luminescence property and can be suggested as a selective fluorescence sensor for detecting Fe 3+ and MnO 4 − ions.
Two new 3D Cd( ii)-MOFs have been constructed from a tetrakis(4-carboxybiphenyl)ethylene ligand, namely [Cd 4.25(tcbpe) 3]·0.25(C 4H 11N)·7.5DEF (NLMOF-1) and [Cd 2K(H 2tcbpe)(Htcbpe)] n ·4DEF (NLMOF-2). Single-crystal X-ray analysis revealed that NLMOF-1 is of 3D framework constituted by 1D metal chains containing six-nuclear secondary building units (SBUs) and one-dimensional channel, while NLMOF-2 also exhibits a 3D structure in which the 1D channel is blocked by coordinated K ions, resulting in poor chemical stability. NLMOF-1 possesses excellent stability in both water and common organic solvents, conducive to investigating its utility as a chemical sensor. Fluorescence sensing studies show that NLMOF-1 is characteristic of highly sensitive and selective quenching effects toward Fe 3+ ions in DMF, DMA, and acetonitrile, as well as MnO 4 − ions in H 2O, DMA, and acetonitrile. The above results suggest that NLMOF-1 can be considered a potential fluorescent sensor for detecting Fe 3+ and MnO 4 − ions.