Synthesis and characterization of alkali metal salts bearing a phenalenyl-based tridentate ligand

Abstract A series of alkali metal salts bearing a phenalenyl-based N,N,N-tridentate ligand was systematically characterized by spectroscopic and computational methods. The electronic absorption spectra of alkali metal salts exhibited bathochromic shift compared to that of the corresponding free ligand. TD-DFT calculations suggest that alkali metal salts possess narrower HOMO-LUMO gaps than the free ligand. In addition, the natural charges for the alkaline metal cations are increased from lithium to heavier alkali metals, resulting in an increase in the negative charge within the phenalenyl ligand, leading to a destabilizing of the energies of occupied molecular orbitals involved in the bathochromic shift.