Luminescent Zn(II) and Cd(II) coordination polymers based on naphthalene tetracarboxylic acid and 4,4'-bipyridine for sensing of nitrobenzene, Fe³⁺ and Cr₂O₇²⁻ ions

Abstract

Two luminescent Zn(II) and Cd(II) metal-organic frameworks (MOFs) containing 1,4,5,8-naphthalene tetracarboxylic acid (H₄L’) and 4,4'-bipyridine (4bpy), [ZnL(4bpy)_0.5(DMA)]_n (1) and [CdL(4bpy)_0.5]_n (2) (L = 1,8-monoanhydride-1,4,5,8-naphthalenetetracarboxylate, DMA = N,N-dimethyl acetamide), were synthesized and characterized through X-ray diffraction, IR, and UV-Vis spectroscopy. 1 shows a 1D linear chain structure, while 2 shows a 2D baluster structure. Both show multiple H bonding and π-stacking interactions. Both compounds show ligand-based luminescence in the range 400-500 nm with contributions from both ligands. The luminescence is strongly dependent on the presence of potentially coordinating molecules. Luminescence quenching experiments show good sensitivities in detecting nitrobenzene (NB), Fe³⁺ and Cr₂O₇²⁻.

Keywords:

• Metal-organic frameworks (MOFs)
• Zn(II) and Cd(II)
• 1,4,5,8-Naphthalenetetracarboxylic acid
• Selective fluorescent sensing

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was financially supported by Anyang Normal University College Student Innovation Fund Project (No. 202110479087) and the Key grant Project of Science and Technology of Anyang (No. 13).