Synthesis, characterization and structure of lanthanide nitrate complexes with 2-azacyclononanone (AZA)

Complexes with composition [Ln(NO3)(3)(AZA)(3)] (Ln=Nd, Eu, Gd, Tb, Ho and Er) were synthesized and characterized by CHN elemental analyses and lanthanide titration with EDTA. IR spectra show that they are anhydrous and the ligands (AZA) bonded through the carbonyl oxygen; nitrate counter-ions are bidentate, linked to the central ions. The emission spectrum of the europium complex was interpreted in terms of a D-3h distorted to C-3v symmetry. The structure, determined by X-ray single crystal studies is described as a distorted tricapped trigonal prism with the AZA Ligands bonded to one of the bases of the prism and nitrates with one oxygen bonded to one of the bases of the prism and the other forming one of the caps. (C) 2000 Elsevier Science S.A. All rights reserved.