Anhydrous and hydrated rare earth acetylacetonates and their infrared spectra

Article abstract of DOI:10.1021/ic50070a005

Chemical analyses, X-ray powder diffraction patterns, and infrared spectra were used to characterize anhydrous, mono-, di-, and trihydrated rare earth acetylacetonates, and the densities of the hydrated chelates were determined. The anhydrous chelates were obtained by vacuum drying one of the hydrates. They are not appreciably volatile and slowly decompose in vacuo at elevated temperatures. Trihydrates precipitate from 60% aqueous ethanol, dihydrates from cold 95% ethanol, and monohydrates from hot 95% ethanol and a variety of other solvents. The infrared spectra are distinctive for each of the series of hydrates. For a given hydrate series, the spectra obtained are practically independent of the rare earth ion. The most notable exception is the 3100-3600-cm^-1 region of the monohydrates where the high-energy O-H stretching frequency shifts to higher wave numbers and the low-energy O-H stretching frequency shifts to lower wave numbers as the ionic size of the rare earth decreases. Deuterium isotopic substitution studies on the mono- and trihydrates were used to locate the C-H and coordinated H₂O vibrations.