om980665y_si_001.cif (73.97 kB)
Complexes with Platinum−Iridium Bonds: Stepwise Formation of a PtIr2 Cluster Complex
dataset
posted on 1998-12-24, 00:00 authored by Brian T. Sterenberg, Hilary A. Jenkins, Richard J. PuddephattThe reaction of [Pt(dppm)2]Cl2 (dppm = Ph2PCH2PPh2) with [Ir(CO)4]- and dppm in a
1:2:1 ratio leads in a multistep reaction to the new heteronuclear cluster complex [PtIr2(CO)2(μ-CO)(μ-dppm)3], which contains a triangle of metal atoms with each edge bridged by
a dppm ligand and in which only the platinum atom is coordinatively unsaturated. The
initial step in the reaction leads to formation of the neutral and cationic binuclear complexes
[PtIrCl(CO)2(μ-dppm)2] and [PtIr(CO)3(μ-dppm)2]+, respectively. The binuclear complexes then
react with additional [Ir(CO)4]- to form the cluster [PtIr2(CO)4(μ-CO)(μ-dppm)2] by insertion
into a Pt−P linkage; this cluster can exist in two isomeric forms, each containing a triangular
PtIr2 group with the Ir−Ir and one Pt−Ir edge bridged by dppm ligands but differing in
stereochemistry. These isomers equilibrate slowly at room temperature, and each reacts
easily with dppm to form the final cluster complex [PtIr2(CO)2(μ-CO)(μ-dppm)3]. The structures of the complexes [PtIr2(CO)2(μ-CO)(μ-dppm)3], [PtIr(CO)3(μ-dppm)2][PF6], and one
isomer of [PtIr2(CO)4(μ-CO)(μ-dppm)2] have been determined crystallographically, and the
reaction sequence has been determined by monitoring reactions through NMR methods.
