The synthesis and structural characterization of the first tin-bridged ansa half-sandwich complexes via a two-step protocol from Na[η(5)-C(5)H(5)Ru(CO)(2)] and in situ generated Na[η(5)-C(5)H(5)Ni(CO)] are presented. Both compounds are characterized by multinuclear NMR spectroscopy and single-crystal diffraction.
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http://dx.doi.org/10.1021/ic202512y | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences, Flemingovo nám. 542/2, 160 00, Prague 6, Czech Republic.
Chemistry
April 2024
Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Campus Gto, Noria Alta S/N, CP, 36050, Guanajuato, México.
Magnesium-based catalysts are becoming popular for hydroelementation reactions specially using p-block reagents. Based on the seminal report from Schäfer's group (ChemCatChem 2022, 14, e202201007), our study demonstrates that the reaction mechanisms exhibit a far greater degree of complexity than originally presumed. Magnesium has a variety of coordination modes (and access to different hybridizations) which allows this electron-deficient centre to modulate its catalytic power depending on the σ-donor properties of the reagent.
View Article and Find Full Text PDFChem Commun (Camb)
August 2022
Department of Chemistry, Faculty of Natural Sciences and Technology Saarland University Campus Saarbrücken, 66123 Saarbrücken, Germany.
-Half-sandwich complexes of the group 14 elements germanium, tin and lead are reported, which represent a new class of Lewis amphiphilic tetrylenes and bridge the gap between classical N-heterocyclic systems and group 14 metallocenes. These compounds can form complexes both with carbenes and transition metal fragments.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
April 2014
Unité de Catalyse et Chemie du Solide, CNRS, University Lille 1, Science and Technology, 59655 Villeneuve d'Ascq (France).
A lanthanide half-sandwich complex and a ansa lanthanidocene have been assessed for isoprene-styrene chain shuttling copolymerization with n-butylethylmagnesium (BEM). In the presence of 1 equiv BEM, a fully amorphous multiblock microstructure of soft and hard segments is achieved. The microstructure consists of poly(isoprene-co-styrene) blocks, with hard blocks rich in styrene and soft blocks rich in isoprene.
View Article and Find Full Text PDFChemistry
March 2012
Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, USA.
Two ansa-half-sandwich rare-earth-metal (REM) dialkyl complexes supported by an ethylene-bridged fluorenyl (Flu)-N-heterocyclic carbene (NHC) ligand, [M{C(2)H(4)(η(5)-Flu-κ(1)-NHC)}(CH(2)SiMe(3))(2)] (M=Y, 1; Lu, 2), and a chiral ansa-sandwich samarocene incorporating a C(2) ligand, [Sm(η(5)-C(12)H(8))(2)(thf)(2)] (3), have been investigated for the coordination-addition polymerization of renewable methylene butyrolactones, α-methylene-γ-butyrolactone (MBL) and γ-methyl-α-methylene-γ-butyrolactone ((γ)MMBL). Both ansa-half-sandwich complexes 1 and 2 exhibit exceptional activity for the polymerization of (γ)MMBL at room temperature in dimethylformamide (DMF); with a 0.25 mol% catalyst loading, quantitative monomer conversion can be achieved under 1 min, giving a high turn-over frequency (TOF) of 24,000 h(-1).
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