Reactions of 6,6′-dimethyl-2,2′-bipyridyl with iron(II) in aqueous and non-aqueous media

Reaction of anhydrous FeCl2 with 6,6′-dimethyl-2,2′-bipyridyl (dmby) in non-aqueous media gives the yellow, high spin, tetrahedral complex FeCl2(dmby), which is characterized crystallographically, magnetically and by 1H NMR spectroscopy. In contrast, reaction of FeCl2 · 4H2O with dmby in 0.1 M hydrochloric acid, the method of choice for preparing 3:1 and 2:1 iron(II) complexes of 2,2′-bipyridyl, gives [H2dmby][FeCl4] and [Hdmby][FeCl4], in which the dmby has been protonated. These complexes are also characterized crystallographically.