Two novel coordination polymers with Zn(II): Synthesis, structural characterization, thermal analysis and fluorescent properties

• We have synthesized two novel polymers with mixed-ligands.
• Two polymers show unusual network topology, high thermal stability and strong fluorescent emission.
• Versatile building blocks construct these various coordination polymers.

Under similar hydrothermal synthetic conditions used, a novel flexible ligand 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetonitrile (PPAN), benzenedicarboxylate isomers (H2ip = isophthalate, H2tp = terephthalate) and Zinc(II) acetate, two novel mixed-ligand Zn(II) coordination polymers {Zn3(PPAA)2(μ4-ip)2}n (1) and {Zn2(PPAA)2(μ-tp)}n (2) (PPAA− = 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl)acetate) have been isolated, in 1-2 PPAN ligand is also hydrolyzed into a novel PPAA− ligand. Complex 1 contains 1D double chains of {[Zn(PPAA)]+}n cation structural units, which are further extended by these tetra-dentate μ4-ip2−  ligands forming a novel 2D three-layered framework with (4.82)2(43.62.8)2(43.83)2(48.66.8) topology. While complex 2 contains bi-nuclear [Zn2(PPAA)2]2 + structural units, which are extended by four tetra-dentate μ-tp2−  ligands to link eight neighboring di-nuclear [Zn2(PPAA)2]2 + units ultimately forming a 3D framework with a lim symbol of (4.102)2(42.104) topology. The flexible coordination modes of PPAA− and benzenedicarboxylate isomers also reveal a great potential in the construction of these novel mixed-ligand luminescent frameworks with diverse structural motifs and unique functional properties.

This work presents two Zn(II) coordination polymers based on a novel 2-(3-(pyridin-2-yl)-1H-pyrazol-1-yl) acetate and different benzenedicarboxylate isomers (isophthalate, terephthalate), which exhibit distinct 2D layered and 3D network coordination arrays.Figure optionsDownload as PowerPoint slide