Synthesis, characterization and structure of a diaqua lanthanum bimalonate malonate monohydrate

Abstract

A new complex of lanthanum(III) with malonic acid (H 2L) was synthesized and characterized by elemental analysis, IR spectrum, thermal behaviour and X-ray diffraction either on powder or single crystal, corresponding to the formulation La(H 2O 2) 2 (C 3H 2O 4)(C 3H 3O 4)·H 2O. Both IR and thermal analyses show the presence of bimalonate and malonate. The complex has a mono-dimensional structure along the [010] axis, formed of lanthanum atoms and of malonate groups; the bimalonate groups and the water molecules achieve the three-dimensional structure through hydrogen bonds. The lanthanum close environment can be described in terms of a distorted tetracapped trigonal prism. The malonate is three times-chelating (two four-membered rings and one six-membered ring), while the bimalonate is once chelating (four-membered ring).