Binding of a 2-pyridyl moiety to a B/Sn bidentate Lewis acid

Reaction of the bidentate Lewis acid 1,2-Fc(SnMe₂Cl)(B(Me)Cl) (1, Fc = 1,2-ferrocenylene) with 2-trimethylstannylpyridine gave a complex (2), in which the 2-pyridyl group forms a bridge between the Lewis acidic tin and boron centers. The structure of 2 was confirmed by multinuclear and two-dimensional NMR, single crystal X-ray diffraction, and elemental analysis. The crystal structure shows that the pyridyl moiety is positioned endo relative to the substituted Cp ring and UV-Vis spectroscopy revealed an enhancement of the ferrocene-centered dd transition in comparison to related complexes with pyridine as a terminal ligand.