New Mn-CP as a multi-responsive fluorescent probe for ratiometric sensing toward ascorbic acid and turn-off sensing toward nitrofurazone and acetylacetone

The abuse of environmental and biological related molecules, such as small biomolecules, pharmaceutical antibiotics and volatile organic chemicals has become a hotspot issue of global concern. Thus, exploring accurate and effective techniques for monitoring these species remains a major challenge. Here, by employing semi-rigid tetracarboxylate ligand H4edda, one new 2D Mn-based coordination polymer with formula of [Mn2(edda)(phen)2(H2O)2]n (Mn-CP; H4edda = 5,5′-(ethane-1,2-diylbis(oxy)) diisophthalic acid); phen = 1,10-phenanthroline) has been hydrothermally fabricated. The prepared Mn-CP possesses a sql topology with Schläfli symbol of (44·62). Stability research for Mn-CP reveals that it maintains structural stability and initial fluorescence intensity after soaking in water for one week. Moreover, Mn-CP also displays high structural stability in acidic-basic aqueous solution of broad pH scope (1–13) for 48 h. Importantly, photoluminescence measurements indicate that it shows ratiometric fluorescence response to ascorbic acid (AA) as well as turn-off response toward nitrofurazone (NFZ) and acetylacetone (ACAC). The developed fluorescence probe based on Mn-CP shows merits of high selectivity and low detection limits (33.67 nM, 1.43 nM and 2.29 μM for AA, NFZ and ACAC, respectively). The possible mechanisms have been thoroughly explored through exhaustive experimental surveys and theories calculations. The CP-based multi-responsive fluorescent probe designed in this work extends the application of such materials in environmental and biological related fields.