School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS (UK).
Angew Chem Int Ed Engl. 2014 Feb 10;53(7):1804-8. doi: 10.1002/anie.201308395. Epub 2014 Jan 21.
The reactions of iron chlorides with mesityl Grignard reagents and tetramethylethylenediamine (TMEDA) under catalytically relevant conditions tend to yield the homoleptic "ate" complex Fe(mes)3 (mes=mesityl) rather than adducts of the diamine, and it is this ate complex that accounts for the catalytic activity. Both Fe(mes)3 and the related complex Fe(Bn)3 (Bn=benzyl) react faster with representative electrophiles than the equivalent neutral [FeR2 (TMEDA)] complexes. Fe(I) species are observed under catalytically relevant conditions with both benzyl and smaller aryl Grignard reagents. The X-ray structures of Fe(Bn)3 and Fe(Bn)4 were determined; Fe(Bn)4 is the first homoleptic σ-hydrocarbyl Fe(III) complex that has been structurally characterized.
