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.