4,4′-(1,2-Phenylenebis(methyleneoxy))dibenzoate based Cd(II)-coordination polymer: A turn-off-on photoluminescent sensor against ascorbic acid and aspirin

Abstract

A new Cd(II)-coordination polymer (CP) [Cd(bpe)_0.5(L)] (1) has been synthesized employing 4,4′-(1,2-phenylenebis(methyleneoxy))dibenzoic acid (H₂L) and 1,2-bis(4-pyridyl)ethylene (bpe) ligands and characterized spectroscopically as well as by single-crystal X-ray diffraction which revealed that 1 is a 2D polymeric layer, in which the metal–ligand formation is built by the interesting H₂L bridging ligand. The CP 1 exhibits turn-off photoluminescent sensing of ascorbic acid (VC) showcasing limit of detection and K_SV of 1.325 × 10⁻⁵ M and 9.22 × 10³ M⁻¹, respectively. Theoretical calculations indicate that the turn-off sensing of VC by 1 can be accredited to the electron/energy transfer and non-covalent interactions between 1 and VC. Interestingly, the VC@1 material exhibited restoration in photoluminescent emission on adding acetyl salicylic acid (ASA) and hence can be used as turn-on sensor for the selective and sensitive detection of ASA with limit of detection towards ASA to be 2.757 × 10⁻⁵ M having K_SV value of 4.43 × 10⁴ M⁻¹ The explanation for the restoration in photoluminescence intensity of VC@1 on adding ASA has been rendered with theoretical calculations.