Spectral and thermal studies of light lanthanide complexes with 4-methoxy-3-nitrobenzoic acid

4-Methoxy-3-nitrobenzoates of light lanthanides with a metal to ligand rati o of 1:3 have been obtained as hydrated salts. They have colours typical of Ln(3+) ions (Pr-green, Nd-pink, Sm-cream, and La, Ce, Eu and Gd-white). Th e carboxylate group appears to be a bidentate chelating ligand. 4-Methoxy-3 -nitrobenzoates of light lanthanides are crystalline compounds. During heat ing in air, they decompose explosively. Therefore, their thermal stability was studied in the temperature range 273-523 K. The complexes dehydrate in one or three steps. The solubilities of complexes were measured in water at 293 K. They are in the order of 10(-4) mol dm(-3).