A heterobimetallic YLi3tris(binaphthoxide) catalyst (YLB) promoted a 1,4-addition of O-methylhydroxylamine in high enantiomeric excess (up to 97% ee). Catalyst loading was reduced to as little as 0.5 mol %, still affording the 1,4-adduct in 96% yield and 96% ee. A high concentration of substrates and the scalability of the present system is also practically useful. The results suggested that the heterobimetallic catalysis was not deactivated even in the presence of excess amine under highly concentrated conditions. A Y and Li bimetallic cooperative function was essential for a high catalyst turnover number.
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http://dx.doi.org/10.1021/ja038688d | DOI Listing |
Dalton Trans
December 2024
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Jiangwan Campus, Fudan University, Shanghai 200438, China.
The phosphaguanidinate rare-earth-metal bis(aminobenzyl) complexes [(PhP)C(NCHPr-2,6)]Ln(CHCH NMe-) (Ln = Y(1-Y) and Lu(1-Lu)) were synthesized by the protonolysis of (PhP)[C(NHR)(NR)] (R = 2,6-(Pr)CH) with Ln(CHCHNMe-) (Ln = Y and Lu). Interestingly, the ring-opening rearrangement product [-MeNCHCHC(NCHPr-2,6)]Lu(CHCHNMe-)[O(CH)PPh] (2) was obtained when the acid-base reaction was carried out in THF solution at 60 °C for 36 h. Additionally, the trinuclear homometallic yttrium multimethyl/methylidene complex {[(PhP)C(NCHPr-2,6)]Y(μ-Me)}(μ-Me)(μ-CH) (3) was synthesized by the treatment of 1-Y with AlMe (2 equiv.
View Article and Find Full Text PDFChem Sci
December 2024
Department of Chemistry, Seoul National University Seoul 08826 Republic of Korea +82 2 880 6653.
Biological CO/CO interconversion catalyzed at the Ni/Fe heterobimetallic active site of anaerobic carbon monoxide dehydrogenases (CODHs) offers important insights for the design of efficient and selective synthetic catalysts for CO capture and utilization (CCU). Notably, this organometallic C interconversion process is mediated at a three-coordinate nickel site. Extensive research has been conducted to elucidate the redox and structural changes involved in substrate binding and conversion.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC). Avenida Américo Vespucio 49, 41092 Sevilla, Spain.
Bimetallic complexes have demonstrated a great ability to enhance the activity of monometallic systems for bond activation and catalysis. In this work, we explore the opposite approach: using a second metal to passivate the activity of another by reversible bimetallic inhibition. To do so we have synthesized a family of nine electrophilic gold complexes of formula Au(PR)(NTf) ([NTf] = [N(SOCF)]) that can act as inhibitors in the semihydrogenation of terminal and internal alkynes catalyzed by the iconic iridium Vaska complex IrCl(CO)(PPh).
View Article and Find Full Text PDFDalton Trans
December 2024
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 00 Prague, Czech Republic.
C-H bond functionalisation has developed into a powerful synthetic methodology that is applicable to a wide array of substrates, including organometallic compounds. In this study, racemic, planar-chiral 1,2-dihydroferroceno[]isoquinoline and analogous helical compounds with one or two additional -fused benzene rings were synthesised by palladium-catalysed C-H bond activation/cyclisation of -[(bromoaryl)methyl]--(methylsulfonyl)aminoferrocenes. These starting materials are readily accessible from FcNHSOMe (Fc = ferrocenyl) and appropriate vicinal bromo-(bromomethyl)arenes.
View Article and Find Full Text PDFChemistry
November 2024
School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, 6012, New Zealand.
The potassium aluminyl K[Al(NON)] ([NON]=[O(SiMeNDipp)], Dipp=2,6-iPrCH) reacts with group 14 chloroamidinates E(Am)Cl (E=Ge, Sn, Pb. [Am]=[tBuC(NDipp)]) to form (NON)Al-E(Am) Lewis pairs with unsupported Al-E bonds, including the first structurally authenticated Al-Pb bond. Analysis using spectroscopic (NMR, UV-vis and Mössbauer for E=Sn), X-ray diffraction and computational (DFT, QTAIM, TD-DFT) methods conclude an Al-E σ-bond derived from a Lewis basic Al and a Lewis acidic tetrylene, with back-donation from the E s-orbital lone pair donor NBO to acceptor NBOs on Al that are derived from s/p-orbitals.
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