A water-stable new luminescent Cd(Ⅱ) coordination polymer for rapid and luminescent/visible sensing of vanillin in infant formula

• A water-stable new luminescent Cd(Ⅱ) coordination polymer (LCP 1 ) was constructed. • LCP 1 can be used as a fluorescent sensor for the detection of vanillin. • The limit of detection of vanillin was as low as 1.41 μM. • Paper-based sensor for visual recognition detection of vanillin was developed. Establishing a simple and rapid method for the detection of vanillin is necessary and significant. Herein, we synthesized a new 3D luminescent coordination polymer (LCP) [Cd(4-bmnpd)(BA)]( 1 ) {4-bmnpd = N , N ′-bis(4-methylpyridine-4-yl)-2,6-naphthalene dicarboxylamide, H 2 BA = 2[(4-carboxymethyl phenoxy) benzoic acid]} with a semi-rigid bis-pyridine-bis-amide and dicarboxylate mixed ligands under solvothermal condition. X-ray diffraction analysis revealed that 1 is a 5-connected 3D framework structure. The effect of solvents and pH on the luminescence intensity of 1 was investigated. LCP 1 was stable and the luminescence intensity almost unchanged in different solvents as well as in the pH range of 3–11. Fluorescence sensing studies showed that LCP 1 can detect vanillin by fluorescence quenching and has good anti-interference properties toward the substances commonly found in infant formula. The limit of detection of vanillin was as low as 1.41 μM. The fluorescence quenching mechanism of LCP 1 was analyzed in detail. In addition, we developed cheap paper-based sensor for visual recognition detection of vanillin.