FTIR SPECTROSCOPIC EVIDENCE OF NICKEL–CARBOXYLATE COORDINATION IN A Ni-MOF-74-TARGETED MATERIAL

The interaction of nickel ions with 2,5-dihydroxyterephthalic acid (H4DOBDC) was evaluated through comparison of the FTIR spectra of the initial ligand and a nickel-containing product prepared by solvothermal treatment. The material was obtained from nickel nitrate hexahydrate and H4DOBDC in a DMF–ethanol–water system at 100 °C for 24 h. Spectra were recorded on a Bruker ALPHA II spectrometer. The ligand showed a carbonyl-related band near 1680 cm−1, while the final material exhibited prominent features at 1556 and 1411 cm−1, tentatively assigned to asymmetric and symmetric carboxylate stretching. Additional bands at 1455, 1361, 1240, 1200, 1118, 889 and 815 cm−1 support changes in the ligand environment and retention of its aromatic backbone. FTIR evidence favors nickel–ligand coordination but cannot, by itself, establish crystallographic phase purity.