Synthesis spectroscopic and structural properties of transition metal complexes of the o-xylyl diphosphine o-C6H4(CH2PPh2)2

The systematic coordination chemistry of the wide-angle diphosphine o-C6H4(CH2PPh2)(2) (L-1) has been investigated with metal ions from Groups 9-11 in order to explore the consequences of the steric demands of the phosphine and its flexibitity towards different oxidation states and coordination geometries. The products isolated include the tetrahedral [CoX2(L-1)] (X = Cl, Br or I), the very distorted square planar [Rh(L-1)(2)](+), [M(cod)(L-1)](+) (M = Rh or Ir), square planar [NiX2(L-1)] (X = Cl or Br), [M'Cl-2(L-1)] (M'= Pd or Pt), the chloro-bridged [Pd2Cl2(L-1)(2)](2+), [Pd(L-1)(2)](2+), the tetrahedral [M"(L-1)(2)](+) (M" = Cu, Ag or Au) and the dinuclear [(AuCl)(2)(L-1)]. Chemical oxidation of some of the complexes are described, giving examples of Co(III), Ni(III) and Pt(IV) species. Where possible the products have been characterised by IR, UV-vis, NMR (H-1, P-31, Cu-63 and Pt-195 as appropriate) spectroscopies. mass spectrometry and microanalysis. Crystal structures of six representative examples confirm the coordination environments in particular species and illustrate the steric demands of L-1. L-1 is a versatile ligand which can readily alter its chelate bite angle to accommodate a range of coordination geometries (the P...P distances within the chelate rings varies by >0.5 Angstrom), and the presence of the rigid aromatic ring in the C-4 backbone leads to some preorganisation favouring cis chelation. It also shows a preference for low coordination numbers and this results in some unexpected products. (C) 2004 Elsevier Ltd. All fights reserved.