LAUSR

A series of complexes of the type [Ln(Se2P(phenyl)2)3(CH3CN)x] (x = 1 or 2) have been synthesized and structurally characterized for Ln = La–Lu (excluding Pm). The complexes are straightforward to prepare and crystallize and are soluble in solvents typically used in nanoparticle synthesis. Solution-phase thermolysis of these complexes formed lanthanide diselenide or LnSe2–x nanosheets, for Ln = La–Ho, except Eu, which formed EuSe. By contrast, the smallest lanthanides Ln = Er–Lu formed Ln2Se3 nanomaterials. The lanthanide dichalcogenides are rare-earth analogues of the transition metal dichalcogenides and exhibit similar properties, including small band gaps, charge density waves, antiferromagnetism, and superconductivity. The lanthanide diselenide nanomaterials exhibited highly anisotropic growth and were phase pure with the exception of CeSe2 (which also formed a cerium oxide and cerium ultraphosphate). The lateral nanosheet dimensions, based on transmission electron microscopy (TEM), range from ∼50 to ...