Flash Communication: Strained and Bimetallic Structures of Rhodium and Iridium Germyl Complexes with Phosphinoamido Ligands

In the coordination
chemistry of heavier tetrylenes (:ER2, where E = Si, Ge,
Sn, Pb), chelating P,N-donor ligands occupy a
privileged position, though phosphinoamido ligands, [R2P–NR′]−, have been barely investigated.
Herein, we report the synthesis and structural characterization of
such complexes, whose structures drastically differ depending on
the group 9 metal precursor used. Strained four-membered {P–N–Ge–M}
metallacycles (M = Rh, Ir) are produced from the reaction of phosphinoamido
germylenes with [MCl2Cp*]2 precursors (Cp* =
η5-C5Me5). At variance, [MCl(COD)]2 dimers are not broken apart; instead, they afford bimetallic
species featuring bridging phosphinoamido–germyl and chloride
ligands between the two metals. All new compounds were isolated on
a preparative scale and spectroscopically characterized and their
structures confirmed by X-ray diffraction. Computational studies support
the σ-donor character of the Ge–M interaction and the
absence of significant π-backbonding.