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

4-Methoxy-3-nitrobenzoates of heavy lanthanides with a metal to ligand ratio of 1:3 have been obtained as tetrahydrates. They have colours typical for Ln(3+) ions (Ho: cream, Er: salmon,Tb, Dy, Tm, Yb, Lu: white). The carboxylate group appears to be a bidentate chelating ligand. 4-Methoxy-3-nitrobenzoates of heavy lanthanides are crystalline compounds. During heating in air they decompose explosively. Therefore their thermal stability was studied in the temperature range 273-523 K. The complexes dehydrate in one step. Their solubilities were measured in water at 293 K. They are in the orders of 10(-3)-10(-4) mol/dm(3).