Preparation and crystal structures of two monomeric lanthanide(III) complexes containing betaine and nitrato ligands: [Ln(bet) 2(NO 3) 3(H 2O) 2] (LnLa and Sm)

Abstract

Two monomeric lanthanide(III) complexes containing carboxylato and nitrato ligands, [Ln(bet) 2(NO 3) 3(H 2O) 2] (bet = trimethylammonioacetate, LnLa and Sm), have been prepared and characterized by X-ray crystallography. Although the complexes crystallized in different space groups, they adopt analogous structures, with the Ln atom being surrounded in a distorted square-antiprismatic environment by two monodentate carboxylato groups three chelate nitrato groups and two water molecules. The LnO bond lengths are in the ranges 2.489(2)–2.710(3) and 2.19(1)–2.86(2) Å for the La and Sm complexes, respectively. The uncoordinated carboxy oxygen atoms form intramolecular hydrogen bonds with the aqua ligands.