Synthesis of two polymorphic Cu-based coordination polymers of 1,2,4-benzenetricarboxylic acid along with a carbon-coated composite for the selective degradation of organic dyes

Two polymorphic Cu-based coordination polymers (CPs) based on the ligand 1,2,4-benzenetricarboxylic acid (H3BTC) have been prepared via solvothermal synthesis. Each of these CPs (denoted as 1 and 2) possessed the same formula [Cu(1,2,4-H2BTC)2]-4H(2)O but they each exhibited a distinct crystalline phase. These CPs were structurally characterized via elemental analyses, Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) and single crystal X-ray diffraction techniques. The title CPs display versatile structural features with 1D and 2D frameworks. Complex 1 exhibits a 2D layer, and two carboxyl groups belonging to the 1,2,4-H2BTC anion are deprotonated, which link the Cu(II) ions together to generate a 2D sheet. Meanwhile, complex 2 consists of a 1D chain with different coordination modes from that of 1. The influence of the aromatic polycarboxylic ligand on the structures of Cu-based complexes is discussed herein. On this basis, a 2D carbon-coated copper nanoparticle composite (Cu@C) was prepared by using the 1D Cu-based CP as a precursor. Furthermore, the selective adsorption and photocatalytic properties of Cu@C have also been investigated in detail.

Automated summary

Two polymorphic Cu-based coordination polymers (CPs) were prepared using the same ligand but exhibited distinct crystalline phases with versatile structural features including 1D and 2D frameworks. The CPs were structurally characterized and the influence of the aromatic polycarboxylic ligand on Cu-based complexes was discussed. Additionally, a 2D carbon-coated copper nanoparticle composite was prepared using one of the CPs as a precursor, and its selective adsorption and photocatalytic properties were investigated.