Hypersensitivity in the 4f-4f absorption spectra of tris (acetylacetonato) neodymium(III) complexes with imidazole and pyrazole in non-aqueous solutions. Effect of environment on hypersensitive transitions

► Structurally similar eight-coordinate complexes of neodymium are synthesized. ► The 4f-4f absorption spectra are investigated in non-aqueous solvents. ► Methanol, isopropanol and acetonitrile are coordinating solvents. ► Pyridine and DMSO are coordinating solvents by replacing the ancillary ligands. ► Pyridine is most effective in promoting the 4f-4f intensity.