Cationic, neutral, and anionic allyl magnesium compounds: unprecedented ligand conformations and reactivity toward unsaturated hydrocarbons.

摘要: Starting from bis(allyl)magnesium [Mg(C3H5)2], a set of cationic, neutral, anionic, and dianionic allyl magnesium compounds has been isolated characterized, including [Mg(C3H5)(THF)5][B(C6F5)4] (3), [Mg(C3H5)2(1,4-dioxane)(THF)] (2), [KMg(C3H5)3(THF)] (6), [MMg(C3H5)4] (8: M = K2; 9: Ca). In solution, the ligands display fluxional behavior, even at low temperatures. Single crystal X-ray analysis reveals unusual μ2-η1:η3- unprecedented μ3-η1:η3:η3-coordination modes in heterobimetallic 6 [8·(THF)2]. Density functional theory calculations confirm that these metal–allyl conformations are energetically stable. The have investigated as initiators for butadiene polymerization ethylene oligomerization. initiation properties, higher reaction rates, distinctively different those monometallic species. Reactivity trends depend on formal charge magnesiu...