Synthesis and crystallographic characterization of diphenylamide rare-earth metal complexes <i>Ln</i>(NPh<sub>2</sub>)<sub>3</sub>(THF)<sub>2</sub> and [(Ph<sub>2</sub>N)<sub>2</sub> <i>Ln</i>(μ-NPh<sub>2</sub>)]<sub>2</sub>
Acta crystallographica. Section E, Crystallographic communications