A threefold interpenetrated three-dimensional cobalt(II) coordination polymer with highly sensitive sensing for nitrofurazone in aqueous medium

A novel Co^II-based coordination polymer, poly[[μ-4,4′-bis(2-methyl-1H-imid<!?up><!?tlsb><!?down>azol-1-yl)-1,1′-biphenyl-κ²N³:N^3′](μ-5-nitrobenzene-1,3-dicarboxylato-κ²O¹:O³)cobalt(II)], [Co(C₈H₃NO₆)(C₂₀H₁₈N₄)] or [Co(NO₂-BDC)(4,4′-BMIBP)]_n, (I), was synthesized successfully via a hydrothermal reaction. The synthesis employed 5-nitrobenzene-1,3-dicarboxylic acid (NO₂-H₂BDC) as the organic linker, 4,4′-bis(2-methyl-1H-imidazol-1-yl)-1,1′-biphenyl (4,4′-BMIBP) as the N-donor auxiliary ligand and cobalt(II) nitrate hexahydrate as the metal source. Structural characterization revealed that (I) crystallizes in a unique three-dimensional framework featuring a threefold parallel interwoven dmp network topology. Photoluminescence studies demonstrated that (I) exhibits remarkable sensitivity and selectivity for the detection of nitrofurazone (NFZ) in aqueous solution. Furthermore, systematic investigations were conducted to elucidate the potential fluorescence quenching mechanisms of (I) toward NFZ.