The ligand-to-metal charge transfer excited state of [Re(dmpe)₃]²

The ligand-to-metal charge transfer (LMCT) transitions of [Re(dmpe)₃]²⁺ (dmpe = bis-1,2-(dimethylphosphino)ethane) were interrogated using UV/Vis absorbance spectroscopy, photoluminescence spectroscopy, and time-dependent density functional theory. The solvent dependence of the lowest energy charge transfer transition was quantified; no solvatochromism was observed. TD-DFT calculations reveal the dominant LMCT transition is highly symmetric and delocalized involving all phopshine ligand donors in the charge transfer, providing an understanding for the absence of solvatochromism of [Re(dmpe)₃]²⁺.