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

Abstract

Two series of seven lanthanide metal coordination polymers (Ln-CPs) formulated as {[Ln(dttpa)1.5(H2O)2]·H2O}n [Ln = La3+ (1), Ce3+ (2), Nd3+ (3), Sm3+ (4) and Eu3+ (5)] and {[Ln (dttpa)1.5(H2O)]·xH2O}n [Ln = Tb3+ (6) and Er3+ (7), x = 0.75] have been successfully constructed using Ln3+ ions and 2,5-di(1H-1,2,4-triazol-1-yl)terephthalic acid (H2dttpa) 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 {42·84}{44·62}2{49·66}2, and crystallize in the triclinic space group P1̄. Interestingly, Eu-CP (5) effectively sensitizes the visible emission of Tb3+ 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 dttpa2- are a kind of promising functional material.