An Adaptable Chelating Diphosphine Ligand for the Stabilization of Palladium and Platinum Carbenes

Group 10 metal carbenes are proposed
in catalytic transformations;
however, their isolation remains difficult without the presence of
a heteroatom donor. The adaptable cis and trans coordinating ligand
PterP (1,2-bis­(2-(diisopropylphosphino)­phenyl)­benzene)
is key in stabilizing two-coordinate palladium and platinum(0) precursors.
Reacting these precursors with di-p-tolyldiazomethane
((p-tol)2CN2) leads to the
formation of the unprecedented trigonal-planar diarylcarbenes [(PterP)­MC­(p-tol)2] (M = Pd,
Pt), upon transformation of the trans coordinating ligand into a wide-bite,
cis-coordinating ligand. Both palladium and platinum diarylcarbenes
were characterized by multinuclear NMR spectroscopy. The unusual stability
of the platinum analogue allowed its characterization via X-ray crystallography.
Furthermore, the reactivity of the palladium and platinum diarylcarbenes
with Ph2SiH2 and CH3I was investigated.