Solvent influences on the molecular aggregation of magnesium aryloxides: synthesis, crystal structure, and solution characterization of Mg(OAr)_2(L)_3 (OAr = DMP, DIP, TCP) and [Mg(DIP)_2]_3

摘要

Magnesium aryloxides were prepared !n a variety o.fsolvents throu~ tpe reaction of dibuty) magnesium with sterically varied aryl alcohols: 2,6-dimethylphenol (H~DMP), 2,6-diisopropylphenoJ (H-DIP), and 2,4,64richlorophenol (H- TCP). Upon using a sufficiently strong Lewis-basic solvent,. the solvated monomeric species Mg(DMP)2(PY)3 (I, PY = pyridine), Mg(DIP)2(THF)3' (2a, THF= tetrahydrofuran) Mg(TCP)2(THF)3 (3) were isolated. Each of these complexes possesses a five-coordinate magnesium that adopts a trigonal bipyramidal ~ometry; In the absence ofa Lewis base, the reaction with H-DIPyields a soluble trinuclearcomplex, [Mg(DIP)2b (2b).The Mgmetal centers in2b adopt a linear arrangement with afour'-coordinate central metal while the oute, metal centers are reduced to just three-coordinate. Solution spectroscopic methods suggest that while 2b remains intact, the monomeric species (I, 2a, and 3) are involved in equilibria which facilitate intermolecular ligand transfer.