The ambiguous behaviour of diphosphines towards the quasilinear iron(i) complex [Fe(N(SiMe3)2)2]- - between inertness, P-C bond cleavage and C-C double bond isomerisation

Chelating phosphines are widely used as robust and reliable ligands in catalysis. We show that the anionic iron(i) complex [Fe-I(N(SiMe3)(2))(2)](-) is able to selectively cleave a P-aryl bond of 1,2-bis(diphenylphosphino)benzene. Furthermore, the related cis-1,2-bis(diphenylphosphino)-ethylene (dppee) binds not to the P donors but to the ethylene unit, and is (catalytically) transformed to the trans-isomer.