School of Chemistry, Monash University, PO Box 23, Melbourne, VIC, 3800, Australia.
Chemistry. 2010 Jan 18;16(3):938-55. doi: 10.1002/chem.200902425.
The preparation and characterization of a series of magnesium(II) iodide complexes incorporating beta-diketiminate ligands of varying steric bulk and denticity, namely, (ArNCMe)(2)CH (Ar=phenyl, ((Ph)Nacnac), mesityl ((Mes)Nacnac), or 2,6-diisopropylphenyl (Dipp, (Dipp)Nacnac)), (DippNCtBu)(2)CH ((tBu)Nacnac), and (DippNCMe)(Me(2)NCH(2)CH(2)NCMe)CH ((Dmeda)Nacnac) are reported. The complexes [((Ph)Nacnac)MgI(OEt(2))], [((Mes)Nacnac)MgI(OEt(2))], [((Dmeda)Nacnac)MgI(OEt(2))], [((Mes)Nacnac)MgI(thf)], [((Dipp)Nacnac)MgI(thf)], [((tBu)Nacnac)MgI], and [((tBu)Nacnac)MgI(DMAP)] (DMAP=4-dimethylaminopyridine) were shown to be monomeric by X-ray crystallography. In addition, the related beta-diketiminato beryllium and calcium iodide complexes, [((Mes)Nacnac)BeI] and [{((Dipp)Nacnac)CaI(OEt(2))}(2)] were prepared and crystallographically characterized. The reductions of all metal(II) iodide complexes by using various reagents were attempted. In two cases these reactions led to the magnesium(I) dimers, [((Mes)Nacnac)MgMg((Mes)Nacnac)] and [((tBu)Nacnac)MgMg((tBu)Nacnac)]. The reduction of a 1:1 mixture of [((Dipp)Nacnac)MgI(OEt(2))] and [((Mes)Nacnac)MgI(OEt(2))] with potassium gave a low yield of the crystallographically characterized complex [((Dipp)Nacnac)Mg(mu-H)(mu-I)Mg((Mes)Nacnac)]. All attempts to form beryllium(I) or calcium(I) dimers by reductions of [((Mes)Nacnac)BeI], [{((Dipp)Nacnac)CaI(OEt(2))}(2)], or [{((tBu)Nacnac)CaI(thf)}(2)] have so far been unsuccessful. The further reactivity of the magnesium(I) complexes [((Mes)Nacnac)MgMg((Mes)Nacnac)] and [((tBu)Nacnac)MgMg((tBu)Nacnac)] towards a variety of Lewis bases and unsaturated organic substrates was explored. These studies led to the complexes [((Mes)Nacnac)Mg(L)Mg(L)((Mes)Nacnac)] (L=THF or DMAP), [((Mes)Nacnac)Mg(mu-AdN(6)Ad)Mg((Mes)Nacnac)] (Ad=1-adamantyl), [((tBu)Nacnac)Mg(mu-AdN(6)Ad)Mg((tBu)Nacnac)], and [((Mes)Nacnac)Mg(mu-tBu(2)N(2)C(2)O(2))Mg((Mes)Nacnac)] and revealed that, in general, the reactivity of the magnesium(I) dimers is inversely proportional to their steric bulk. The preparation and characterization of [((tBu)Nacnac)Mg(mu-H)(2)Mg((tBu)Nacnac)] has shown the compound to have different structural and physical properties to [((tBu)Nacnac)MgMg((tBu)Nacnac)]. Treatment of the former with DMAP has given [((tBu)Nacnac)Mg(H)(DMAP)], the X-ray crystal structure of which disclosed it to be the first structurally authenticated terminal magnesium hydride complex. Although attempts to prepare [((Mes)Nacnac)Mg(mu-H)(2)Mg((Mes)Nacnac)] were not successful, a neutron diffraction study of the corresponding magnesium(I) complex, [((Mes)Nacnac)MgMg((Mes)Nacnac)] confirmed that the compound is devoid of hydride ligands.
报告了一系列含有不同空间位阻和齿密度的β-二酮亚胺配体的镁（II）碘化物配合物的制备和表征，即(ArNCMe)(2)CH（Ar=苯基，((Ph)Nacnac)，mesityl((Mes)Nacnac)，或 2,6-二异丙基苯基(Dipp，(Dipp)Nacnac)），(DippNCtBu)(2)CH((tBu)Nacnac)和(DippNCMe)(Me(2)NCH(2)CH(2)NCMe)CH((Dmeda)Nacnac)。配合物[((Ph)Nacnac)MgI(OEt(2))]，[((Mes)Nacnac)MgI(OEt(2))]，[((Dmeda)Nacnac)MgI(OEt(2))]，[((Mes)Nacnac)MgI(thf)]，[((Dipp)Nacnac)MgI(thf)]，[((tBu)Nacnac)MgI]和[((tBu)Nacnac)MgI(DMAP)]（DMAP=4-二甲氨基吡啶）通过 X 射线晶体学被证明是单体。此外，还制备并晶体学表征了相关的β-二酮亚胺铍和钙碘化物配合物[((Mes)Nacnac)BeI]和[{((Dipp)Nacnac)CaI(OEt(2))}(2)]。尝试使用各种试剂还原所有金属（II）碘化物配合物。在两种情况下，这些反应导致了镁（I）二聚体[((Mes)Nacnac)MgMg((Mes)Nacnac)]和[((tBu)Nacnac)MgMg((tBu)Nacnac)]。用钾还原[((Dipp)Nacnac)MgI(OEt(2))]和[((Mes)Nacnac)MgI(OEt(2))]的 1:1 混合物，得到结晶学表征的配合物[((Dipp)Nacnac)Mg(mu-H)(mu-I)Mg((Mes)Nacnac)]的低产率。迄今为止，尝试通过还原[((Mes)Nacnac)BeI]，[{((Dipp)Nacnac)CaI(OEt(2))}(2)]或[{((tBu)Nacnac)CaI(thf)}(2)]形成铍（I）或钙（I）二聚体的所有尝试都没有成功。进一步研究了镁（I）配合物[((Mes)Nacnac)MgMg((Mes)Nacnac)]和[((tBu)Nacnac)MgMg((tBu)Nacnac)]对各种路易斯碱和不饱和有机底物的进一步反应性。这些研究导致了配合物[((Mes)Nacnac)Mg(L)Mg(L)((Mes)Nacnac)]（L=THF 或 DMAP），[((Mes)Nacnac)Mg(mu-AdN(6)Ad)Mg((Mes)Nacnac)]（Ad=1-金刚烷基），[((tBu)Nacnac)Mg(mu-AdN(6)Ad)Mg((tBu)Nacnac)]和[((Mes)Nacnac)Mg(mu-tBu(2)N(2)C(2)O(2))Mg((Mes)Nacnac)]，并揭示了一般来说，镁（I）二聚体的反应性与其空间位阻成反比。[((tBu)Nacnac)Mg(mu-H)(2)Mg((tBu)Nacnac)]的制备和表征表明，该化合物具有与[((tBu)Nacnac)MgMg((tBu)Nacnac)]不同的结构和物理性质。用 DMAP 处理前者得到了[((tBu)Nacnac)Mg(H)(DMAP)]，其 X 射线晶体结构表明它是第一个结构确证的端基镁氢化复合物。尽管尝试制备[((Mes)Nacnac)Mg(mu-H)(2)Mg((Mes)Nacnac)]没有成功，但对相应的镁（I）配合物[((Mes)Nacnac)MgMg((Mes)Nacnac)]的中子衍射研究证实该化合物不含氢化物配体。
