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

Brown, Michael D., Levason, William, Reid, Gillian and Watts, Rebecca (2005) Synthesis spectroscopic and structural properties of transition metal complexes of the o-xylyl diphosphine o-C6H4(CH2PPh2)2. Polyhedron, 24 (1), 75-87. (doi:10.1016/j.poly.2004.10.008).

Abstract

The systematic coordination chemistry of the wide-angle diphosphine o-C6H4(CH2PPh2)2 (L1) 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 flexibility towards different oxidation states and coordination geometries. The products isolated include the tetrahedral [CoX2(L1)] (X = Cl, Br or I), the very distorted square planar [Rh(L1)2]+, [M(cod)(L1)]+ (M = Rh or Ir), square planar [NiX2(L1)] (X = Cl or Br), [M?Cl2(L1)] (M? = Pd or Pt), the chloro-bridged [Pd2Cl2(L1)2]2+, [Pd(L1)2]2+, the tetrahedral [M?(L1)2]+ (M? = Cu, Ag or Au) and the dinuclear [(AuCl)2(L1)]. 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 (1H, 31P, 63Cu and 195Pt 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 L1. L1 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 Å), and the presence of the rigid aromatic ring in the C4 backbone leads to some preorganisation favouring cis chelation. It also shows a preference for low coordination numbers and this results in some unexpected products.

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Contributors

Author: Gillian Reid

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