Structure and luminescence properties of trichloridothallium(III) complexes with phenanthroline derivatives

Abstract

Two thallium(III) complexes, [Tl(5-mphen)Cl₃(DMSO)] (1) and [Tl(5,6-dmphen)Cl₃(DMSO)]·DMSO (2) were prepared from the reaction of TlCl₃·4H₂O with 5-methyl-1,10-phenanthroline (5-mphen) and 5,6-dimethyl-1,10-phenanthroline (5,6-dmphen) ligands in DMSO solvent through methanol diffusion. Their crystal structures were determined by the X-ray diffraction method. These complexes have a bidentate nitrogenous ligand and a DMSO molecule with three chloride anions attached to a Tl(III) metal in a distorted octahedral environment, where both complexes were crystallized in the same space group ($P\overline{1}$) and crystal system (triclinic). The ¹H NMR data confirms the stability of the compounds in the DMSO moiety. The luminescence study revealed that their luminescence behaviour is varied in comparison with corresponding ligands, although the thallium complexes exhibit the same structure and the only difference is the number of the methyl group on the phenanthroline ligand. Interestingly, complex 1 demanded a considerable enhancement (nine times), in comparison with the related phenanthroline ligand, a well-known material for OLEDs.