Cyclopropylmagnesium scorpionates: A missing member of the series with both staggered and eclipsed rotamers in the crystal
Résumé
The reaction of the hydrotris(3,5-dimethylpyrazolyl)borate potassium salt KTpMe2 with [Mg(c-C3H5)2(dioxane)x] gives [TpMe2Mg(c-C3H5)] (1) in 70 % yield. Full characterization includes an X-ray diffraction study, which reveals the presence of both staggered and eclipsed rotamers around the Mg–C bond of 1 in the unit cell. There is no evidence for any agostic interaction. Complex 1 does not undergo the Schlenk equilibrium. The complex [(F12-Tp4Bo,3Ph)Mg(c-C3H5)] (2) containing a hydrotris(tetrafluoro-3-phenylindazolyl)borate scorpionate ligand, is obtained in 20 % yield. Complex 2 proved to be significantly more labile than 1, solutions of 2 giving readily [Mg(F12-Tp4Bo,3Ph)2] (3). This study emphasizes the importance of tuning the steric and electronic properties of the scorpionate ligands for the stabilization of heteroleptic magnesium alkyl complexes.