205993-24-4Relevant academic research and scientific papers
Salt metathesis as an alternative approach to access aluminium(i) and gallium(i) ?-diketiminates
G?rls, Helmar,Kretschmer, Robert,Kysliak, Oleksandr
supporting information, p. 6377 - 6383 (2020/06/03)
Salt metathesis,i.e.the reaction of sodium ?-diketiminate with (AlCp*)4and GaCp*, respectively, is a valuable pathway to access the respective aluminium(i) and gallium(i) ?-diketiminatesIandII. The protocol gives better yields compared to the established procedures and avoids the use of strong reducing agents such as metallic potassium. Furthermore, the aluminium(i) ?-diketiminateIwas found to react with itself and yields upon C-N bond cleavage and hydrogen-atom transfer the asymmetric dinuclear aluminium(iii) complexVthat is readily separated fromIby crystallisation. The reaction mechanism has been probed by means of DFT and DLPNO-CCSD(T) calculations and the computational findings are in good agreement with the experimental observations.
Thorium(IV) and uranium(IV) halide complexes supported by bulky β-diketiminate ligands
Monreal, Marisa J.,Wright, Robert J.,Morris, David E.,Scott, Brian L.,Golden, Jeffery T.,Power, Philip P.,Kiplinger, Jaqueline L.
, p. 1423 - 1434 (2013/05/09)
The coordination behavior of the bulky β-diketiminate ligands N,N′-bis(2,6-diisopropylphenyl)pentane-2,4-diiminate (LMe) and N,N′-bis(2,6-diisopropylphenyl)-2,2-6,6-tetramethylheptane-3,5-diiminate (LtBu) toward ThX4(THF)4 (X = Br, I) and UCl4 has been investigated. The reaction between K[LMe] and ThX4(THF)4 (X = Br, I) afforded the mono(β-diketiminate)thorium(IV) halide complexes (LMe)ThX 3(THF) (X = Br (7), I (8)). The same reaction carried out with the more sterically demanding K[LtBu] gave (LtBu)ThBr 3(THF) (9) and (LtBu)ThI3 (11). All attempts to install two β-diketiminate ligands on thorium(IV) were unsuccessful, giving the mono(β-diketiminate)thorium(IV) halide complex and unreacted K[LMe] or K[LtBu]. However, complex 9 was shown to react with smaller anions such as K[C5H4Me] to give the mixed-ligand methylcyclopentadienyl β-diketiminate complex (L tBu)Th(C5H4Me)Br2 (10). Complexes 7-11 represent rare examples of thorium complexes featuring only one β-diketiminate ligand, and complexes 9-11 are the first examples of thorium and halide complexes supported by the LtBu framework. In a similar manner, both K[LMe] and K[LtBu] were shown to react with UCl4 to give the corresponding mono(β-diketiminate)uranium(IV) chloride complexes (LMe)UCl3(THF) (12) and (L tBu)UCl3 (13). Complex 13 represents the first example of a uranium complex featuring the LtBu framework. Efforts to prepare the bis(β-diketiminate)uranium(IV) complex (LMe) 2UCl2 by reacting 2 equiv of K[LMe] with UCl4 led instead to the interesting cationic diuranium complex [{(LMe)(Cl)U}2(μ-Cl)3][Cl] (14). Complexes 7-14 have been characterized by a combination of 1H and 13C{1H} NMR spectroscopy, elemental analysis, electrochemistry, and UV-visible-near-IR spectroscopy. Several complexes have also been characterized by X-ray crystallography, and a discussion of their structures is presented. NMR spectroscopy and the X-ray structures demonstrate that the β-diketiminate ligand is symmetrically bound to the actinide metal in the LMe complexes and is asymmetrically bound to the actinide metal in the LtBu complexes. In all cases the actinide(IV) metal centers lie out of the plane of the β-diketiminate ligand NCCCN backbone by ～1-2 A. The electronic spectroscopy data on K[LMe], (LMe)ThI3(THF) (8), and (LMe)UCl 3(THF) (12) suggest relatively weak metal-(β-diketiminate) ligand bonding interactions, although small perturbations in the characteristics of the β-diketiminate π-π* bands with changes in the the metal ion are consistent with some metal-ligand orbital interactions. This new class of mono(β-diketiminate)thorium and -uranium halide complexes promises to provide a robust platform for developing new chemistry of the actinides.
β-Diketiminate-Stabilized Magnesium(I) Dimers and Magnesium(II) Hydride Complexes: Synthesis, Characterization, Adduct Formation, and Reactivity Studies
Bonyhady, Simon J.,Jones, Cameron,Nembenna, Sharanappa,Stasch, Andreas,Edwards, Alison J.,McIntyre, Garry J.
body text, p. 938 - 955 (2010/08/20)
The preparation and characterization of a series of magnesium(II) iodide complexes incorporating β-diketiminate ligands of varying steric bulk and denticity, namely, [(ArNC-Me)2CH]- (Ar = phenyl, (PhNacnac), mesityl (MesNacnac), or 2,6-diisopropyl-phenyl (Dipp, DippNacnac)), [(DippNC-tBu) 2CH]- (tBuNacnac), and [(DippNC-Me)(Me2NCH 2CH2NCMe)CH]- (DmedaNacnac) are reported. The complexes [(PhNacnac)MgI(OEt2)], [(MesNacnac)MgI(OEt2)], [(DmedaNacnac)MgI(OEt2)], [(MesNacnac)MgI-(thf)], [(DippNacnac)MgI(thf)], [(tBuNac-nac)MgI], and [(tBuNacnac)MgI-(DMAP)] (DMAP = 4-dimethylamino-pyridine) were shown to be monomeric by X-ray crystallography. In addition, the related β-diketiminato beryllium and calcium iodide complexes, [(MesNacnac)BeI] and [{(DippNacnac)-CaI(OEt2)} 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, [(MesNacnac)MgMg(MesNacnac)] and [(tBuNacnac)MgMg(tBuNacnac)]. The reduction of a 1:1 mixture of [(DippNacnac)MgI(OEt2)] and [(MesNacnac)MgI(OEt 2)] with potassium gave a low yield of the crystallo-graphically characterized complex [(DippNacnac)Mg(μ-H)(μ-I)Mg(MesNacnac)]. All attempts to form beryllium(I) or calcium(I) dimers by reductions of [(MesNacnac)BeI], [{(DippNacnac)CaI(OEt2)}2], or [{(tBuNacnac)CaI(thf)}2] have so far been unsuccessful. The further reactivity of the magnesium(I) complexes [(MesNacnac)MgMg(MesNacnac)] and [(tBuNacnac)MgMg(tBuNacnac)] towards a variety of Lewis bases and unsaturated organic substrates was explored. These studies led to the complexes[(MesNacnac) Mg(L)Mg(L)(MesNacnac)](L = THF or DMAP), [(MesNacnac)Mg-(μ-AdN 6Ad)Mg(MesNacnac)] (Ad = 1- adamantyl), [(tBuNacnac)Mg(μ-Ad-N 6Ad)Mg(tBuNacnac)], and [(MesNacnac)Mg(μ-tBu2N 2C2O2)Mg- (MesNacnac)] and revealed that, in general, the reactivity of the magnesium(I) dimers is inversely proportional to their steric bulk. The preparation and characterization of [(tBuNacnac)Mg(μ- H)2Mg(tBuNacnac)] has shown the compound to have different structural and physical properties to [(tBuNacnac)-MgMg(tBuNacnac)]. Treatment of the former with DMAP has given [(tBuNacnac)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 [(MesNacnac)Mg(μ-H) 2Mg(MesNacnac)] were not successful, a neutron diffraction study of the corresponding magnesium(I) complex, [(MesNacnac)Mg-Mg(MesNacnac)] confirmed that the compound is devoid of hydride ligands.
