Oxidation of the octa-(ethyl)diphosphaferrocene

The octa-(ethyl)-diphosphaferrocene (1) reacts with NOBF4 in dichloromethane to yield a polymer (2) featuring diphosphaferrocene ligands (1) that bridge [Fe(NO)2] units through their two phosphorus atom lone pairs. The X-ray crystal structure of 2 has been recorded. The formation of the 1-P-fluoro-2,3,4,5-tetra-(ethyl)-phosphole oxide as a by-product demonstrates that phosphaferrocenium (2) is sensitive towards substitution reaction at iron and nucleophilic attack at phosphorus. Oxidation of 1 with iodine in dichloromethane yielded the corresponding phosphaferrocenium cation [FeI4]− complex (4) which has been characterized structurally. The formation of 4 probably results from the partial decomposition of the diphosphaferrocenium cation having [I3]− as the counter anion.