Lanthanide nitrate complexes of the redox active ligand (η5C5H4P(O)Ph2)2Fe

The synthesis of complexes of (η5C5H4P(O)Ph2)2Fe = L with lanthanide nitrates is described. The single crystal X-ray structures for La(NO3)3L(μ-L)La(NO3)3L (1), [Eu(NO3)2L2]2[Eu(NO3)5] (2), [Ho(NO3)2L2]2[Ho(NO3)5] (3) and [Lu(NO3)2L2] NO3 (4) are reported. Trends in Ln–O bond distances cannot be explained by the lanthanide contraction alone. The cyclic-voltammetric (CV) oxidation–reduction behaviour of 1, 2, 4 and Dy(NO3)3L2 · 2H2O is described. This was reversible on a timescale of a few seconds in all cases. In our hands the CV behaviour of L also seemed reversible on this timescale, although attempted chemical oxidation of L led to the isolation of [FeL2(NO3)2]NO3 (5) which was characterised by X-ray crystallography.

The reaction of L with lanthanide nitrates leads to complexes with three distinct structural types. The redox properties have been investigated and show a dependence on the size of the lanthanide ion.Figure optionsDownload as PowerPoint slide