The reaction of iron carbonyl complexes with bis(trifluoromethyl)-phosphine and tetrakis(trifluoromethyl)diphosphine

Abstract

The reaction of Fe(CO)5 or Fe3(CO)12 with the secondary phosphine (CF3)2PH at 80–90° gives Fe2(CO)6[P(CF3)2]2 and H2Fe2(CO)6[P(CF3)2]2, a metal dihydride complex which is shown by n.m.r. spectroscopy to exist in solution as cis- and trans-isomers with axial hydrogen atoms; the deuteride, D2Fe2(CO)6[P(CF3)2]2 is prepared from Fe3(CO)12 and (CF3)2PD. The action of the phosphine on Fe2(CO)9 at 20°, however, gives Fe(CO)4[P(CF3)2H], which decomposes to the dihydride on heating, whilst with (π-C5H5)2Fe2(CO)4, π-C5H5Fe(CO)2P(CF3)2 is formed. The diphosphine [(CF3)2P]2 reacts with all three binary iron carbonyls to give Fe2(CO)6[P(CF3)2]2. The action of (CF3)2PH or [(CF3)2P]2 on dinitrosyldicarbonyliron leads to the formation of Fe2(NO)4[P(CF3)2]2.