Copper-, palladium-, and platinum-containing complexes of an asymmetric dinucleating ligand

The coordination chemistry of an asymmetric dinucleating hexadentate ligand LH₂ comprising neutral alkyltriamine and potentially dianionic dicarboxamido-pyridyl donor sets with copper, palladium, and platinum has been explored. Monometallic, dicopper, and heterodinuclear Cu-Pd and-Pt complexes have been prepared and characterized, including by NMR, EPR, UV-vis, and IR spectroscopy and X-ray crystallography. For example, the monometallic complexes [(LH₂)MCl]X (M = Cu, X = OTf; M = Pd or Pt, X = Cl) were prepared, wherein the metal(II) ions are coordinated to the triamine portion and the pyridyldicarboxamide is unperturbed. Treatment of LH₂ with [MesCu]_x (Mes = mesityl) provided a monocopper(I) complex, again with the metal coordinated only to the trialkylamine donor set. Reaction of [(LH₂)CuCl]OTf with NaOMe resulted in an unexpected migration of the copper(II)-chloride fragment to the pyridyldicarboxamide site to yield Na[LCuCl], from which a dicopper complex LCu₂Cl₂ and mixed-metal complexes LCu(Cl)M(Cl) (M = Pd, Pt) were prepared by addition of CuCl₂ or MCl₂, respectively. The heterodinuclear complexes were also prepared by addition of CuCl₂ to [(LH₂)MCl]Cl.