Ir and Au complexes with mixed-valent bidentate ligands
Bidentate phosphorus ligands are highly valued for their excellent chelating abilities when forming metal complexes. Iminobis(diorganophosphines) R2PNHPR2 (R = alkyl, aryl) feature a central nitrogen group in the backbone and are as versatile as the extensively studied diphosphines. Particularly, bis(diphenylphosphino)amine (dppa) remains of great interest because it readily forms complexes with numerous metals in a variety of coordination modes. Selective oxidation of one P atom in dppa allows the synthesis of the mixed-valent P(III)/P(V) systems Ph2P(E)NHPPh2 (E = O, S, Se) in which the incorporation of the chalcogen moiety creates potentially hemilabile ligands that can impart interesting chemical properties to their metal complexes. This work presents the synthesis and characterization of Ir and Au complexes containing the mono-chalcogenide ligands Ph2P(E)NHPPh2 (E = S, Se). Overall, 31P NMR spectroscopy proved to be a valuable tool for studying the reactivity of the synthesized complexes, as it enables monitoring the response of each phosphorus atom in the ligand depending on its chemical environment.