Construction of Isomorphous Coordination Polymers with 2‐(3‐(pyridin‐2‐yl)‐1H‐pyrazol‐1‐yl) acetate Ligand: Structures, Fluorescent Temperature Sensing, and Magnetic Properties

Abstract

In this work, four isomorphous two‐dimensional (2D) complexes, [M(PPA)(HCOO)]n (M=Zn (1), Co (2), Ni (3) and Cd (4)) have been synthesized under solvothermal conditions by mixed 2‐(3‐(pyridin‐2‐yl)‐1H‐pyrazol‐1‐yl) acetate (PPA) with transition metal ion (Zn2+, Co2+, Ni2+ or Cd2+). Single‐crystal and powder X‐ray diffraction show that the four complexes are isomorphous. Due to different electronic configurations for Zn2+, Co2+, Ni2+, and Cd2+, the solid‐state fluorescence properties of 1 and 4, and the temperature dependence of magnetic susceptibility of 2 and 3 were investigated, respectively. The results show that 1 and 4 have obvious blue light emission at the range of 310 to 430 nm with 1.37 % of the quantum yield and 3.80 ns of the lifetime for 1 and 1.67 % and 2.43 ns for 4, respectively. Notably, the intensity‐based fluorescent temperature sensing reveals that both of them can be used as luminescent thermometers. Magnetic investigation of 2 and 3 reveals that strong antiferromagnetic interactions exist within the paramagnetic centers, Co(II) or Ni(II), with −29.09 K of Weiss constant for 2 and −64.02 K for 3, respectively.