Synthesis and reactivity of mono(amidinate) organoiron(II) complexes

The mono(amidinate) iron(II) ferrate complex [{PhC(NAr)2}FeCl(µ-Cl)Li(THF)3] (1, Ar = 2,6-iPr2C6H3) was prepared and was found to undergo ligand redistribution in non-coordinating solvents to give the homoleptic [{PhC(NAr)2}2Fe] (2) as the only isolable product. Reaction of 1 with alkylating agents also induces this redistribution, but the presence of pyridine allows isolation of the four-coordinate 14 VE monoalkyl complex [{PhC(NAr)2}FeCH2SiMe3(py)] (4). Generation of the 12 VE alkyl via pyridine abstraction from 4 by B(C6F5)3 again induced ligand redistribution. Attempts to trap a 12 VE alkyl species with CO led to the isolation of a dimeric Fe(0)–Li–ferrate complex (3) with a carbamoyl ligand, derived from CO insertion into the iron–amidinate bond.