Novel mononuclear mixed ligand complexes of heavy lanthanide trifluoroacetates with diethylenetriamine

Abstract

Seven mixed ligand complexes of lanthanide trifluoroacetates with diethylenetriamine [Ln(tfa)2(deta)2](tfa) (Ln=Y, Dy−Lu; Htfa — trifluoroacetic acid, deta — diethylenetriamine) with mononuclear structure were synthesized and characterized by powder X-ray diffraction, IR and NMR spectroscopy, TGA, conventional elemental analysis; crystal structure of [Y(tfa)2(deta)2](tfa) was determined by single crystal X-ray diffraction. The structure of the new type consists of mononuclear complex cations [Y(tfa)2(deta)2]+ and outer-sphere tfa− anions connected into dimeric associates by intra-dimeric H-bonds. The complexes in crystalline state demonstrate high stability to storage in air and also retain tfa− anions within the coordination sphere in solution according to the results of NMR spectroscopy. Stability of [Ln(tfa)2(deta)2](tfa) species was explained by DFT calculations. This allows their application as precursors of rare earth fluorides illustrated by synthesis of NaYF4 powder and thin films.