Seven Ln(III) coordination polymers with two kinds of geometric coordination but the same 3D topological property: luminescence sensing and magnetic property.

Two series of seven lanthanide metal coordination polymers (Ln-CPs) formulated as {[Ln(dttpa) 1.5 (H 2 O) 2 ]·H 2 O} n [Ln = La 3+ (1), Ce 3+ (2), Nd 3+ (3), Sm 3+ (4) and Eu 3+ (5)] and {[Ln (dttpa) 1.5 (H 2 O)]· x H 2 O} n [Ln = Tb 3+ (6) and Er 3+ (7), x = 0.75] have been successfully constructed using Ln 3+ ions and 2,5-di(1 H -1,2,4-triazol-1-yl)terephthalic acid (H 2 dttpa) via a hydrothermal method. Their 3D structures are fully characterised by Fourier transform infrared (FT-IR) spectroscopy, X-ray single-crystal analyses, powder diffraction analyses (PXRD), elemental analyses (EAs) and thermogravimetric analyses (TGAs). All Ln-CPs display the same topological property with the point symbol of {4 2 ·8 4 }{4 4 ·6 2 } 2 {4 9 ·6 6 } 2 , and crystallize in the triclinic space group P 1̄. Interestingly, Eu-CP (5) effectively sensitizes the visible emission of Tb 3+ and shows high selectivity and stable response with the lowest detection limit of 9.88 nM. Furthermore, Tb-CP (6) acts as a good luminescence sensor to detect nitrobenzene (NB) with a detection limit of 12.5 nM. In addition, the magnetic susceptibility measurement for Er-CP (7) further shows that compounds constructed by dttpa 2- are a kind of promising functional material.