A Ni/Cu-containing phosphinate material based on 2-carboxyethyl(phenyl)phosphinic acid was synthesized under hydrothermal conditions and characterized using FT-IR (Fourier Transform Infrared Spectroscopy), SEM (Scanning Electron Microscopy) and EDAX (Energy Dispersive X-ray Analysis) analysis. The FT-IR spectra suggest the coordination of the phosphinate group to the metal, while SEM revealed compact aggregated particles of the compound. EDAX analysis confirmed the simultaneous presence of both Ni(II) and Cu(II) metals in the synthesized material. DFT (Density Functional Theory) calculations performed on the corresponding mononuclear Ni-CEPPA and Cu-CEPPA models indicated that the Cu complex possesses a smaller HOMO–LUMO energy gap (2.72 eV) than the Ni analog (3.43 eV), suggesting higher electronic reactivity. The obtained material was preliminarily evaluated for Methylene Blue removal, exhibiting an adsorption capacity of 170.24 mg/g. These results suggest that mixed Ni/Cu phosphinate materials may represent potential candidates for adsorption-related applications.

A nickel(II) coordination material derived from 2-carboxyethyl(phenyl)phosphinic acid (CEPPA) was obtained under hydrothermal conditions and investigated by elemental analysis, Fourier-Transform Infrared spectroscopy (FT-IR), Scanning Electron Microscopy coupled with Energy-Dispersive X-ray analysis (SEM/EDX), Thermogravimetric Analysis (TGA), and Powder X-ray Diffraction (PXRD). Indexing and powder-profile refinement of the PXRD data support a monoclinic crystalline phase. FT-IR data are consistent with ligand deprotonation and changes in the phosphinate/carboxylate environments upon reaction with Ni(II), without assigning a unique coordination mode from vibrational data alone. The material was incorporated into a PVC/o-NPOE membrane containing NaTPB and evaluated for potentiometric naloxone detection. A linear response was obtained over 10⁻²–10⁻⁵ M with a slope of 52.67 mV decade⁻¹ and an experimental detection limit of 8.5 × 10⁻⁶ M. The results demonstrate the feasibility of integrating the Ni(II)–CEPPA material into a polymeric sensing membrane, while definitive atomic-level structural assignment and specific recognition interactions require additional structural and mechanistic evidence.