Synthesis and Characterization of a Terminal Iron(II)-PH Complex and a Series of Iron(II)-PH Complexes.

Reported is the reaction of a series of iron(II) bisphosphine complexes with PH in the presence of NaBAr [where BAr = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate]. The iron(II) bisphosphine reagents bear two chlorides or a hydride and a chloride motif. We have isolated six different cationic terminal-bound PH complexes and undertaken rigorous characterization by NMR spectroscopy, single crystal X-ray diffraction, and mass spectrometry, where the PH often remains intact during the ionization process. Unusual bis- and tris-PH complexes are among the compounds isolated. Changing the monophosphine from PH to PMe results in the formation of an unusual Fe cluster, but with no PMe being ligated. Finally, by using an iron(0) source, we have provided a rare example of a terminally bound iron-PH complex.