A Zn(II)-Based Sql Type 2D Coordination Polymer as a Highly Sensitive and Selective Turn-On Fluorescent Probe for Al(3+)

A luminescent coordination polymer with the overall formula {[Zn(tr(2)btd)(bpdc)]∙DMF}(n) (where tr(2)btd = 4,7-di(1H-1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole; bpdc = 4,4′-biphenyldicarboxylate) was synthesized and characterized by single-crystal and powder X-ray diffraction, thermogravimetric, infrared spectroscopy, and elemental analyses. Luminescent properties of the obtained compound were studied in detail both in the solid state and as a suspension in N,N-dimethylacetamide (DMA). It was found that {[Zn(tr(2)btd)(bpdc)]∙DMF}(n) exhibits bright turquoise luminescence with excellent quantum efficiency and demonstrates turn-on fluorescence enhancement effect upon soaking in DMA Al(3+) solution. Fluorescence titration experiments were carried out and the detection limit for Al(3+) ions was calculated to be 120 nM, which is among the lowest reported values for similar materials. Moreover, compound demonstrated excellent selectivity and reusability, and the mechanism of the response is discussed. These results indicate that {[Zn(tr(2)btd)(bpdc)]∙DMF}(n) is a promising probe for sensitive fluorescent Al(3+) detection.