Selective fluorescent sensing of LMOFs constructed from tri(4-pyridylphenyl)amine ligand

Three new luminescent metal-organic frameworks (LMOFs), [Zn(tppa)(ndc)] (1), [Cd(tppa)(oba)] (2), [Zn₂(tppa)(bpdc)₂] (3) (tppa = tri(4-pyridylphenyl)amine, ndc = 1,4-naphthalenedicarboxylic acid, oba = 4,4'-oxydibenzoic acid, bpdc = 4,4'-biphenyldicarboxylic acid) have been synthesized by solvothermal method. Complexes 1 and 2 are 2-D two-fold interpenetrating structures, aligning into a 3-D structure through C-H⋯π stacking interactions, while 3 is a 5-fold interpenetrating three-dimensional structure. The internal quantum yields (IQYs) of complexes 1-3 are 32.7%, 45.7% and 24.0% (λ _ex = 365 nm), separately. Furthermore, all the complexes show different luminescence signal changes towards aromatic volatile organic compounds (AVOCs). Complex 1 exhibits a high sensitivity in the detection of both Fe³⁺ and Cr³⁺ with large quenching coefficients of K _sv 2.57 × 10⁴ M^-1 and 2.96 × 10⁴ M^-1, respectively. All these results demonstrated potential applications in chemical sensing.