Group 1 cyclopentadienide/group 1,14-tert-butoxide adducts: Ion exchange and coordination polymer formation

To probe the structural effects of Group 1 (M = Na, K) and Group 14 (El = Ge(II), Sn(II)) ions on adducts between MCp and MEl(OtBu)3 salts, the metal ions were systematically varied and the solid-state structures of the adducts were studied by single-crystal X-ray methods. KCp maintained its undulating chain structure, albeit decorated with isolated K(THF)2Sn(OtBu)3 units. The initially-linear NaCp chain, however, became intercalated with MEl(OtBu)3 moieties, and the ensuing polymer adopted a zigzag-chain structure. A mixture of KCp and NaGe(OtBu)3 underwent an ion exchange to give NaCp and KGe(OtBu)3, revealing that tridentate [Ge(OtBu)3]− prefers the larger potassium ion to sodium ion.

Graphical abstractMCp (M = Na, K, Cp = C5H5) form non-identical coordination polymers with ternary tert-butoxides of the type MEl(OtBu)3, El = Ge(II), Sn(II). KCp maintains it chain structure, decorated with K(THF)2Sn(OtBu)3 units, but the linear NaCp chain becomes intercalated with the ternary tert-butoxide salts and forms zigzag chains. The salts NaGe(OtBu)3 and KCp undergo cation exchange prior to adduct formation.Figure optionsDownload full-size imageDownload as PowerPoint slide