In: ChemCatChem, 2011, vol. 3, no. 1, p. 167-173
Palladium complexes containing abnormally bound C4-bound dicarbene ligands have been exploited for catalytic alkene hydrogenation. Comparison to normally C2-bound homologues indicates that the carbene bonding mode critically influences the catalytic activity. Good catalytic performance in the hydrogenation of cis-disubstituted olefins and non-isomerizable terminal olefins under mild...
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In: Dalton Transactions, 2009, vol. 35, p. 7168-7178
Main-chain organometallic polymers were synthesized from bimetallic iron(II) complexes containing a ditopic N-heterocyclic carbene (NHC) ligand [(cp)(CO)LFe(NHC∼NHC)Fe(cp)(CO)L]X₂ (where NHC∼NHC represents a bridging dicarbene ligand, L = I⁻ or CO). Addition of a diimine ligand such as pyrazine or 4,4′-bipyridine, interconnected these bimetallic complexes and gave the...
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In: Organometallics, 2009, vol. 28, no. 17, p. 5112–5121
A series of ruthenium(II) complexes have been prepared by using bidentate chelating N-heterocyclic carbene (NHC) ligands that feature different donor groups E (E = olefin, thioether, carboxylate, and NHC). Rigid coordination of all donor sites was concluded from NMR spectroscopy, and the electronic impact of the donor group was evaluated by electrochemical analyses. The chelating donor group had...
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In: Chemistry - A European Journal, 2009///doi: 10.1002/chem.200900249
Sterically similar palladium dicarbene complexes have been synthesized that comprise permethylated dicarbene ligands which bind the metal center either in a normal coordination mode via C2 or abnormally via C4. Due to the strong structural analogy of the complexes, differences in reactivity patterns may be attributed to the distinct electronic impact of normal versus abnormal carbene bonding,...
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In: European Journal of Inorganic Chemistry, 2009, no. 13, p. 1871 - 1881
Oxidative addition of 2-bromopyridine derivatives containing a potentially chelating donor group E (E = NMe₂, SMe, SPh) to palladium(0) gives C,E-bound pyridylpalladium(II) complexes. Mono-, di-, and polymeric palladium complexes are obtained depending on the type of functionalization at the pyridyl nitrogen. With a lone pair at nitrogen, dimetallic products are isolated, while...
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In: New Journal of Chemistry, 2009, vol. 33, p. 462–465
Chiral bis-5,6-pinene bipyridine type ligands have been used to form, through self-assembly reaction, dinuclear coordination compounds which show a highly diastereoselective formation of double helices with copper(I) and silver(I) as coordination centers.
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In: Journal of the American Chemical Society, 2008, vol. 130, no. 41, p. 13534–13535
The [3 + 2] cycloaddition of azides and acetylenes followed by nitrogen quaternization was applied for the generation of novel and highly modular triazolium salts. The selective substitution of the 1,3,4-substitution pattern presets such salts as precursors for a new class of abnormal carbene ligands, thus expanding the family of these high-impact ligands. Metalation of the triazolium salts is...
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In: Dalton Transactions, 2008, vol. 41, p. 5570-5576
Bimetallic homonuclear iron(II) and ruthenium(II) N-heterocyclic carbene complexes have been synthesized and crystallographically analyzed. As a spacer ligand for interconnecting the two redox-active metal centers, a ditopic carbene ligand has been used that comprises two carbene sites annelated to benzene. Detailed electrochemical and spectroelectrochemical analyses of the bimetallic...
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In: Dalton Transactions, 2008, p. 6242 - 6249
Palladation of C2-protected diimidazolium salts with Pd(OAc)₂ afforded complexes comprising C4-bound N-heterocyclic dicarbene ligands. The reactivity of these complexes towards Lewis acids (AgBF₄, AgOAc) and Brønsted acids (H₂SO₄, H₃PO₄, HOAc) revealed that abnormal C4 bonding of the carbenes markedly increases the nucleophilicity of the coordinated palladium center as compared to C2...
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In: Organometallics, 2008, vol. 27, no. 13, p. 3161–3171
Direct metalation of C2-protected diimidozolium salts with RhCl₃ or [RhCl(cod)]₂ and KI afforded a series of new rhodium(III) complexes with abnormally C4-bound, cis-chelating NHC ligands. The complexes were isolated as dimetallic species containing two (μ²-I)₃-bridged rhodium(III) centers. In the presence of coordinating ligands such as CH₃CN, PPh₃, or dppe, the dimeric...
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