Synthesis, structural analysis, and properties of silver-based 1D and 3D coordination polymers

Abstract

In this work, a facile synthesis method was employed to synthesize two silver-based coordination polymers (CPs) with distinct 1D and 3D frameworks using different starting materials. The 3D coordination polymer, [Ag₄(TCPB)]_n·3CH₃OH designated as CP-1, was synthesized using silver trifluoroacetate and a multidentate organic linker, 1,2,4,5-tetrakis(4-carboxyphenyl)benzene (H₄TCPB). Meanwhile, the 1D coordination polymer, [Ag(bpy)]_n(NO₃)_n denoted as CP-2, was synthesized using silver nitrate and a bidentate organic linker, 4,4′-bipyridyl (bpy) as a starting material. Both frameworks exhibit distinct structural and photophysical properties. Single-crystal X-ray diffraction (SCXRD) analysis reveals that CP-1 crystallizes in the triclinic P space group, adopting a robust 3D helical-type structure with [Ag₄(TCPB)] as repeating units. CP-1 possesses uniform porosity and is classified as metal–organic framework (MOF). CP-2, however, crystallizes in the orthorhombic Pnna space group, forming a 1D polymer chain with [Ag(bpy)] as repeating units with NO₃ as the counter ion. These 1D polymer chains shows interionic interactions between Ag-atoms and O-atoms of nitrate anions resulting in a 2D coordination polymer, [Ag(bpy)]_n(NO₃)_n. Electrical neutrality in CP-1 and CP-2 is maintained by the carboxyl groups of TCPB and the oxygen atoms of nitrate ions, respectively. CP-1 exhibits royal blue luminescence and demonstrates good photostability upon UV light exposure, while the CP-2 material shows no luminescence and is unstable under ambient conditions. To sum up, we explored the structure–property relationship of silver-based coordination polymers.