Sequential Reduction and Alkyl Exchange Reactions of Bis(imino)pyridine Dialkyliron(II) with Trimethylaluminum

The sequence of reactions ensuing when the 2,6-bis(imino)pyridine Fe(II) dialkyl complexes [Fe(CH2SiMe3)2(BIP)] react with trimethylaluminum is described in detail. The first step is the reduction of the dialkyl to the corresponding monoalkyl complex [Fe(CH2SiMe3)(BIP)]. In the presence of an excess of trimethylaluminum, these undergo exchange of the remaining CH2SiMe3 group for methyl, and ultimately the methyliron fragment is displaced from the complex, leading to previously known paramagnetic aluminum compounds. The diethylaluminum complex [AlEt2­(iPrBIP)] was obtained when triethylaluminum was used instead of trimethylaluminum.