Synthesis and Characterization of Aliphatic P^PhNHP^Ph-Type Iron-Containing Complexes

The P^PhNHP^Ph ligand of bis[(2-diphenylphosphino)ethyl]ammonium chloride was synthesized by the reaction of bis(2-chloroethyl)amine hydrochloride with potassium diphenylphosphide. This P^PhNHP^Ph ligand can react with ferrous chloride to obtain a mononuclear iron complex [(η²-N,P-P^PhNHP^Ph)₂FeCl₂]. Reaction of this complex with sodium triethylborohydride and iron chloride led to the formation of the [(η³-N,P,N-P^PhNHP^Ph)· Fe(η²-N,P-P^PhNHP^Ph)FeCl₃] complex. [(η²-N,P-P^PhNHP^Ph)₂FeCl₂] complex contains two P^PhNHP^Ph ligands in which only N and P atoms coordinate to the iron center. One iron center of [(η³-N,P,N-P^PhNHP^Ph)· Fe(η²-N,P-P^PhNHP^Ph)FeCl₃] is a five-coordinate structure, while the other iron center coordinates with the free phosphonium atom of the P^PhNHP^Ph ligand.