Synthesis, crystal structures, and electrospray ionisation mass spectrometry investigations of ether- and thioether-substituted ferrocenes

A number of ether- and thioether-substituted ferrocenes (1,1ʹ-bis(1,3-dioxane-2-yl)ferrocene 1, 1,1ʹ-bis(5-methyl-1,3-dioxane-2-yl) ferrocene 2, 1,1ʹ-bis(4-methyl-1,3-dioxane-2-yl)ferrocene 3, 1,1ʹ-bis[(R)-(-)-4-methyl-1,3-dioxane-2-yl]ferrocene 4, 1,1ʹ-bis(4,6-dimethyl1,3-dioxane-2-yl)ferrocene 5, and 1,1ʹ-bis(1,3-dithiane-2-yl)ferrocene 6) were synthesised by direct condensation of 1,1ʹdiformylferrocene with the corresponding diols or dithiols. The crystal structures of 1, 5a, 5b, and 6 were determined by X-ray diffraction studies. Electrospray ionisation mass spectrometry was used to investigate the binding behaviour of 1 and 6 toward alkali as well as transition metal cations. The dioxane-containing species 1 showed high affinity toward Li+ and Na+, whereas the dithiane derivative 6 bound, as expected, preferentially to Hg2+.