Spectroscopic and Electrochemical Trends in Divalent Lanthanides through Modulation of Coordination Environment.

Due to the importance of both visible-light luminescence and lanthanides in modern society, the influence of the ligand environment on complexes of YbII were studied and compared with analogous complexes of EuII. Four ligands with systematically varied electronic and steric characteristics were used to probe the coordination environment and electronic and redox properties of the corresponding YbII-containing complexes. Strong-field nitrogenous donors gave rise to bathochromic shifts, leading to visible-light absorption by YbII. Trends in properties across the series of YbII-containing complexes were compared to trends reported for the analogous EuII-containing complexes, revealing the translatability of coordination environment effects across the divalent lanthanide series. These studies provide valuable information regarding the behavior of small and medium-sized divalent lanthanides outside of the solid state.