Reactive Magnesium Nanoparticles to Perform Reactions in Suspension

Zerovalent magnesium (Mg(0)) nanoparticles are prepared in the liquid phase (THF) by reduction of MgBr$_2$ 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 (d$_{101}$=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 (Ph$_3$SiCl), trichlorphenylsilane (PhSiCl$_3$), 9H-carbazole (Hcbz), 7-azaindole (Hai), 1,8-diaminonaphthalene (H$_4$nda) and N,N’-bis(α-pyridyl)-2,6-diaminopyridine (H$_2$tpda) as exemplary starting materials. The reactions result in the formation of 1,1’-biadamantane (1), [MgCl$_2$(thf)$_2$]×Ph$_6$Si$_2$ (2), [Mg$_9$(thf)$_{14}$Cl$_{18}$] (3), [Mg(cbz)$_2$(thf)$_3$] (4), [Mg$_4$O(ai)$_6$]×1.5 C$_7$H$_8$ (5), [Mg$_4$(H$_2$nda)$_4$(thf)$_4$] (6) and [Mg$_3$(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. ... mehr3–7 represent new coordination compounds using sterically demanding N−H-acidic amines as starting materials. The formation of multinuclear Mg$^{2+}$ complexes with multidentate ligands illustrates the potential of the oxidative approach to obtain novel compounds with Mg(0) nanoparticles in the liquid phase.