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    ABSTRACT: A series of mononuclear, heteroleptic beryllium complexes supported by the monoanionic β-diketiminate ligand [HC{CMeNDipp}2]− (L; Dipp = 2,6-diisopropylphenyl) have been synthesized. Halide complexes of the form [LBeX] (X = Cl, I) and a bis(trimethylsilyl)amide complex were produced via salt metathesis routes. Alkylberyllium β-diketiminate complexes of the form [LBeR] (R = Me, nBu) were obtained by salt metathesis from the chloride precursor [LBeCl]. Controlled hydrolysis of [LBeMe] afforded an air-stable, monomeric β-diketiminatoberyllium hydroxide complex. [LBeMe] also underwent facile protonolysis with alcohols to form the corresponding β-diketiminatoberyllium alkoxides [LBeOR] (R = Me, tBu, Ph). High temperatures and prolonged reaction times were required for protonolysis of [LBeMe] with primary amines to yield the β-diketiminatoberyllium amide complexes [LBeNHR] (R = nBu, CH2Ph, Ph). No reactions were observed between [LBeMe] and silanes, terminal acetylenes, or secondary amines. All compounds were characterized by 1H, 13C, and 9Be NMR spectroscopy and, in most cases, by X-ray crystallography. Reduction of the beryllium chloride complex with potassium metal resulted in apparent hydrogen-atom transfer between two β-diketiminate backbones, yielding two dimeric, potassium chloride bridged diamidoberyllium species. X-ray analysis of a cocrystallized mixture of the 18-crown-6 adducts of these species allowed unambiguous identification of the two reduced diketiminate ligands, one of which had been deprotonated at a backbone methyl substituent and the other reduced by hydride addition to the β-imine position. It is proposed that this process occurs by the formation of an unobserved radical anion species and intermolecular hydrogen-atom transfer by a radical-based hydrogen abstraction mechanism.
    Inorganic Chemistry 12/2012; 51(24). DOI:10.1021/ic3022968 · 4.79 Impact Factor
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    ABSTRACT: Silylamide [Ba{N(SiHMe2)2}2]n reacts with 1,10-phenanthroline (Phen) in toluene to give the donor adduct [Ba{N(SiHMe2)2}2(Phen)]2. X-ray structure analysis revealed a dimeric solid-state structure with two bridging silylamido ligands and Ba···SiH β-agostic interactions, which are most pronounced for the terminal silylamido ligands. Treatment of [Ba{N(SiHMe2)2}2]n with GaMe3 did not lead to the isolation of putative Lewis acid adduct [Ba(μ-{N(SiHMe2)2})(μ-Me)(GaMe2)] but resulted in the soluble, low aggregated barium oxo complex [Ba(μ4-O)(GaMe3)2(toluene)]2, which is reminiscent of inverse crown ethers.
    Berichte der deutschen chemischen Gesellschaft 01/2012; 2012(1). DOI:10.1002/ejic.201101013 · 2.97 Impact Factor
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    ABSTRACT: Divalent metal silylamide complexes of zinc and cobalt and trivalent aluminium isopropoxide were successfully grafted onto large-pore hexagonal channel-like SBA-15 and cubic MCM-48-like periodic mesoporous silica (PMS) KIT-6, to afford hybrid materials Zn[N(SiMe3)2]2@SBA-15, Co[N(SiMe3)2]2(thf)@SBA-15/KIT-6 and {Al(OCHMe2)3}@SBA-15 with well-defined surface species ([triple bond, length as m-dash]SiO)2M(thf)x, [triple bond, length as m-dash]SiOM[N(SiMe3)2](THF)x (x = 0, M = Zn; x = 1, M = Co), [triple bond, length as m-dash]SiOSiMe3 and ([triple bond, length as m-dash]SiO)2Al(OCHMe2) and [triple bond, length as m-dash]SiOAl(OCHMe2)2, respectively. Surface silylamido ligand exchange with 1,4-benzenediol, 1,4-benzenedicarboxylic acid, and biphenyl-4,4'-dicarboxylic acid gave hybrid materials of type [triple bond, length as m-dash]SiOML(solvent)x and ([triple bond, length as m-dash]SiO)2M(solvent)x (L = O(C6H4)OSiMe3, O2C(C6H4)CO2SiMe3, O2C(C6H4)2CO2SiMe3; M = Zn and Co) revealing in situ ligand silylation as a side reaction. Surface isopropoxide/carboxylato ligand exchange generated species ([triple bond, length as m-dash]SiO)2AlL(DMF)x and [triple bond, length as m-dash]SiOAl(OCHMe2)2-yLy (L = O2C(C6H4)CO2H, y ≤ 2) devoid of any secondary functionalization (such as formation of ester groups), offering a potential approach to PMS-encapsulated metal-organic frameworks. All featured surface species were verified by (1)H, (13)C and (29)Si magic angle spinning (MAS) NMR and diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy as well as elemental analysis. Additionally, preservation of the long-range ordered mesostructures was proven by powder X-ray diffraction (PXRD), nitrogen physisorption, and transmission electron microscopy (TEM).
    Dalton Transactions 03/2013; 42:6922-6935. DOI:10.1039/c3dt33041a · 4.10 Impact Factor