Reactive Magnesium Nanoparticles to Perform Reactions in Suspension

Zerovalent magnesium (Mg(0)) nanoparticles are prepared in the liquid phase (THF) by reduction of MgBr₂ either with lithium naphthalenide ([LiNaph]) or lithium biphenyl ([LiBP]). [LiBP]-driven reduction results in smaller Mg(0) nanoparticles (10.3±1.7 nm) than [LiNaph]-driven reduction (28.5±4 nm). The as-prepared Mg(0) nanoparticles are monocrystalline (d₁₀₁=245±5 pm) for both types of reduction. Their reactivity is probed by liquid-phase reaction (THF, toluene) in suspension near room temperature (20-120 °C) with 1-bromoadamantane (AdBr), chlortriphenylsilane (Ph₃SiCl), trichlorphenylsilane (PhSiCl₃), 9H-carbazole (Hcbz), 7-azaindole (Hai), 1,8-diaminonaphthalene (H₄nda) and N,N'-bis(α-pyridyl)-2,6-diaminopyridine (H₂tpda) as exemplary starting materials. The reactions result in the formation of 1,1'-biadamantane (1), [MgCl₂(thf)₂]×Ph₆Si₂ (2), [Mg₉(thf)₁₄Cl₁₈] (3), [Mg(cbz)₂(thf)₃] (4), [Mg₄O(ai)₆]×1.5 C₇H₈ (5), [Mg₄(H₂nda)₄(thf)₄] (6) and [Mg₃(tpda)₃] (7) with 40-80 % yield. 1 and 2 show the reactivity of Mg(0) nanoparticles for C-C and Si-Si coupling reactions with sterically demanding starting materials. 3-7 represent new coordination compounds using sterically demanding N-H-acidic amines as starting materials. The formation of multinuclear Mg²⁺ complexes with multidentate ligands illustrates the potential of the oxidative approach to obtain novel compounds with Mg(0) nanoparticles in the liquid phase.