Synthesis and characterization of manganese(II) and zinc(II) luminescent iminophosphorane complexes

Abstract

The thesis internship was focused on the preparation of iminophosphorane ligands to be coordinated to selected metal centers , with the aim of preparing new luminescent coordination compounds. The reaction with triphenylphosphine and aromatic or benzylic azides afforded the desired monodentate {N=P}-donors. The aromatic iminophosphorane revealed appreciable luminescence at the solid state. The reaction of the ligands with manganese(II) and zinc(II) halides in acetonitrile afforded neutral complexes. The use of protic solvent caused the decomposition of the ligands, and in selected cases the related phosphine oxide complexes were obtained. The luminescence of the zinc(II) complexes resulted to be ligand-based, enhanced by coordination and influenced by the spin-orbit coupling associated to the heavy halides. On the other hand, intense metal-centred luminescence was observed for manganese(II) complexes, in the green region for tetrahedral derivatives and in the reddish orange for higher coordination numbers. The coordination geometry resulted dependent upon the N-bonded substituent. The results with monodentate ligands were confirmed by the use of a bidentate iminophosphoranes obtained from bis(diphenylphosphino)methane.