Complexation associated rearrangement of iminobiphosphines to diphosphinoamines

The reaction of the iminobiphosphines RNPPh2–PPh2, where R = C6H4(p-CN), C6H4(m-CN), C6H4(o-C6H5), C6F5 or C6H4(o-CF3), with one molecular equivalent of M(cod)Cl2 (M = Pd or Pt) results in a rearrangement of the NPP unit to the more commonly encountered P–N–P unit, forming mono-chelating complexes of general formula M{RN(PPh2)2}Cl2. The related reaction of the same range of iminobiphosphines with Pt(cod)Cl2 (but not Pd(cod)Cl2) in 2:1 ratio affords complexes of general formula [Pt{RN(PPh2)2}2]2Cl. All 15 complexes are isolated in moderate to high yield and they have been fully characterised by spectroscopic methods. Six complexes, viz. [M{C6H4(p-CN)N(PPh2)2}Cl2], [M{C6H4(m-CN)N(PPh2)2}Cl2] and [M{C6H4(o-C6H5)N(PPh2)2}Cl2] (M = Pd and Pt), have been characterised in the solid state by single crystal X-ray diffraction analysis.

Graphical abstractIminobiphosphines react with transition metal complexes with a con-committant rearrangement to afford coordinated diphosphinoamines. Several examples are given and six X-ray structures are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide