Cyclopropylmagnesium scorpionates: a missing member in the series with both staggered and eclipsed rotamers in the crystal

Quentin Dufrois; Sonia Mallet-Ladeira; Chiara Dinoi; Michel Etienne

Index: 10.1002/ejic.201800073

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Abstract

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 less kinetically stable 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