Lanthanoid Nitrate Complexes with Some Polyethylene Glycols and Glymes

Abstract

Lanthanoid nitrates (Ln(NO3)3) formed solid complexes with several polyethylene glycols and glymes. The compositions of the complexes were 1:1 (Ln:ligand) for triethylene glycol(EO3), tetraethylene glycol(EO4), pentaethylene glycol(EO5), and tetraglyme, 1:2 (Ln:ligand) for diethylene glycol, 2:1 for heptaethylene glycol, and 4:3 for pentaglyme and hexaglyme. Solid complexes were deposited also for hexaethylene glycol, but their compositions were not definitely determined. The solid complexes obtained here were all deliquescent. The deposition of the complexes was generally interfered with by water in the solution, and was not observed for some heavier lanthanoids when a small amount of water was present in the solution. The solubilities of the solid complexes with EO4 and EO5 increased with an increase in the atomic number of the lanthanoid, a fact suggesting a unique selectivity of the glycols. The infrared absorption bands of polyethylene glycols or glymes in the 1000–1150 cm−1 region became sharper upon the complexing of the glycols or glymes with lanthanoids; this sharpening can be explained by the change in the conformations in the ligand molecules.

Coordination of trivalent lanthanum with polyethylene glycol in the presence of picrate anion: Spectroscopic and X-ray structural studies

“…The results also indicate that the picrate ligand maintains a coordination number of 10 in the lanthanum complexes. This contrasts with the La-PEG-chloride and La-PEG-nitrate complexes, where the coordination polyhedron is inconsistent with a coordination number of 10, but instead a coordination number of 9-12 [1,[9][10][11][12][13][14][15][16][17][18].…”

“…Triethylene glycol (EO3, 99% purity) and tetraethylene glycol (EO4, 99.5% purity) were purchased from Acros (NJ, USA). Pentaethylene glycol (EO5, >97% 11.93 (11.84) 140 purity) and La(NO3)3·7H2O (98% purity) were purchased from Fluka (Buchs, Switzerland). Picric acid (HPic) [(NO2)3C6H2OH, >98% purity) was purchased from BDH (Poole, England).…”

“…The acyclic PEG ligand was coordinated to La 3+ in I-IV, which exhibited pseudo-cyclic behavior (Fig. 2(a-c)) [5][6][7][9][10][11][12][13][14][15][16][17][18][19]. The flexibility of the PEG ligand and the characteristics of its coordination with La 3+ make it very suitable for the formation of complexes.…”

“…Lanthanide complexes with PEG have previously been reported [1,[9][10][11][12][13][14][15][16][17][18][19], while complexes of PEG-Pic coordinated to the lanthanides in the coordination sphere have yet to be described in the literature. Previous work emphasized the structure of lanthanide complexes with PEG but did not report any studies on the spectroscopic and luminescence properties of the compounds.…”

Synthesis, characterization and anticancer activity of 3-formylchromone benzoylhydrazone metal complexes

“…In these complexes, the fcbh - The IR spectra of complexes (1) and (4) exhibit strong bands near 1,100 and 755 cm -1 due to m(P-C) and d(CCH) vibrations, respectively [8,9]. In addition, the spectra of complexes (1) and (7) show bands at 1,387/1,345 and 1,488 cm -1 , respectively, characteristic of ionic and coordinated nitrate NO 3 -, respectively [33]. [28].…”