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.

The pyridyl moiety in the title compound is bridging between a Lewis acidic tin and a boron center. Based on single crystal X-ray and solution NMR studies the preferred isomer shows the pyridyl moiety positioned endo relative to the substituted Cp ring.Figure optionsDownload as PowerPoint slide