Innovative Zinc(II) Metal−Organic Frameworks Featuring Pyridine-Sulfonate-Imine Linkers for Microextraction of Plasticizers and Selective Luminescent Detection of Toxic Oxyanions

Two novel zinc(II)-based metal−organic frameworks, i.e. (MOFs), [Zn2(HL4-Py)2(H2O)2] (UTMOF1) and [Na2Zn5(L4-Py)4(DMF)2(H2O)6] (UTMOF2) (where DMF = dimethylformamide, H2L4-Py = 4-hydroxy-3-{[2-(pyridine-4-carbonyl) hydrazinylidene] methyl} benzene-1-sulfonate), were synthesized via diffusion crystallization, employing diethyl ether as an antisolvent diffusing into a DMF-MeOH-H2O solution containing Zn(CH3COO)2·2H2O and NaH2L4-Py. Single-crystal X-ray diffraction analysis revealed that UTMOF1 features two distinct one-dimensional open channels: a larger hydrophilic channel and a smaller hydrophobic channel. UTMOF2 is a three-dimensional coordination polymer comprising three unique zinc and sodium centers. UTMOF1 was further employed as an adsorbent for the extraction and preconcentration of various additives and plasticizersincluding butylated hydroxytoluene, dibutyl phthalate, diisobutyl phthalate, di(2-ethylhexyl) phthalate, and di(2-ethylhexyl) adipatemigrated from plastic serum containers. This approach demonstrated excellent analytical performance, with quite high extraction recoveries (84−98%), enrichment factors ranging from 420 to 490, broad linear calibration ranges, low limits of detection (0.70−0.87 mg L−1), and quantification (2.31−2.87 mg L−1). Additionally, UTMOF1 exhibited intense blue luminescence in aqueous media, which was selectively quenched by Cr2O72− and MnO4− ions. High Stern−Volmer constants (Ksv) and low detection limits confirmed its outstanding sensing capabilities.