A Novel 2D Nickel(II) Coordination Polymer Based on Trimesic Acid as Ligand For Coordination of Glyphosate

This work presents the synthesis and characterization of a new coordination polymer of the MOF type named Ni-BTC, where Trimesic Acid (H₃BTC) acts as the ligand and nickel as the metal center. The structure was initially determined by Single Crystal X-ray Diffraction (SCXRD), revealing that the MOF has a minimal formula {[Ni(HBTC)(DMF)₂]· x DMF}, exhibiting a 2D dimensionality. The Ni(II) center is hexacoordinated, expanding in the equatorial direction, while N,N' -dimethylformamide (DMF) molecules occupy the axial positions originating from the solvent used in solvothermal synthesis. Additionally, Co-BTC MOF was synthesized, showing an isostructural structure to Ni-BTC, with similar coordination modes and numbers for BTC and DMF ligands. Analysis using Field Emission Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (FESEM-EDS) revealed the presence of two distinct phases in Ni-BTC, highlighting the influence of the counter-ion in modulating phases during synthesis. Ni-BTC was further characterized by thermal methods such as Thermogravimetric Analysis and Differential Thermal Analysis (TGA and DTA), demonstrating moderate thermal stability. Magnetic Susceptibility measurements indicated both metal centers are in the + 2 oxidation state. Finally, the bidentate molecule glyphosate (GLY) was used to coordinate with Ni-BTC, replacing the more labile axial DMF ligands. This coordination was confirmed by Powder X-ray Diffraction (PXRD) and Infrared Spectroscopy (FTIR), along with electrochemical techniques such as Cyclic Voltammetry (CV) and Square Wave Voltammetry (SWV). These results highlight the potential application of glyphosate-modified Ni-BTC in glyphosate detection and removal systems.