Preparation and crystal structures of trans-[Fe(NCMe)2(Ph2PCH2PPh2)2][FeI4]·2H2O and [Fe{Ph2P(O)CH2P(O)Ph2}3][I3]2

Abstract

In an attempt to characterise definitively the species previously reported to be [Fe(NCMe)₂(dppm)]I₂, the structure of [Fe(NCMe)₂(dppm)₂][FeI₄]·2H₂O (dppm = Ph₂PCH₂PPh₂) has been determined. Thus dppm is capable of forming bis(bidentate) complexes with iron(II). However, such materials are air-sensitive, and in attempting to reproduce the synthesis of the dihydrate the novel diphosphine dioxide complex [Fe(dppom)₃][I₃]₂[dppom = Ph₂P(O)CH₂P(O)Ph₂] was actually isolated and characterised by X-ray structure analysis. It is doubtful whether [Fe(NCMe)₂(dppm)]I₂ has ever been prepared.