Reaction of 2,6-Bis(diazaboryl)pyridine with Alkyls of Lithium, Zinc and Magnesium

The reactivity of 2,6-bis(diazaboryl)pyridine (dab(2)py) with the metal alkyls MeLi, Et2Zn and n-Bu2Mg is reported. In all reactions, the alkylation of one boron atom of dab(2)py was observed to yield a new type of anionic pyridine ligand, which forms the respective adducts with [Li(OEt2)](+), [ZnEt](+) or [Mg(n-Bu)](+). The alkylation of the boron atom results in a tetrahedral geometry, which allows for both amine nitrogen atoms to participate in the coordination. The products are highly soluble in all common solvents including alkanes. The reactivity is compared with the one already reported for unsubstituted pyridine, which is alkylated at the 2-position by treatment with MeLi. The reaction of these metal alkyls with the popular terdentate 2,6-diiminopyridine ligand (DIMPY) were previously reported to yield N-alkylated anionic ligands, which subsequently undergo alkyl-migration or deprotonation reactions. Single crystal XRD was performed on the products obtained from the reaction with MeLi and Et2Zn. Attempts to grow crystals for the respective magnesium alkyl complex in a dry ice box yielded a dinuclear complex bridged by two valerate groups instead.