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Université de Fribourg

Catalytic hydrogenation using abnormal N-heterocyclic carbene palladium complexes: catalytic scope and mechanistic insights

Heckenroth, Marion ; Khlebnikov, Vsevolod ; Neels, Antonia ; Schurtenberger, Peter ; Albrecht, Martin

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...

Université de Fribourg

Polyoxometalate-based N-heterocyclic carbene (nhc) complexes for palladium-mediated C-C coupling and chloroaryl dehalogenation catalysis

Berardi, Serena ; Carraro, Mauro ; Iglesias, Manuel ; Sartorel, Andrea ; Scorrano, Gianfranco ; Albrecht, Martin ; Bonchio, Marcella

In: Chemistry, A European Journal, 2010, vol. 16, no. 35, p. 10662–10666

Better together: A novel hybrid N-heterocyclic carbene (NHC) palladium complex, integrating a totally inorganic and polyanionic decatungstate unit, has been synthesized following a convergent strategy. The interplay of the Pd binding domains with the inorganic scaffold is instrumental in accessing multi-turnover catalysis in C-C cross-coupling and aromatic dehalogenation reactions under...

Université de Fribourg

On the electronic impact of abnormal C4-bonding in N-heterocyclic carbene complexes

Heckenroth, Marion ; Neels, Antonia ; Garnier, Michael G. ; Aebi, Philipp ; Ehlers, Andreas W. ; Albrecht, Martin

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,...

Université de Fribourg

Palladium complexes containing potentially chelating pyridylidene-type carbene ligands

Poulain, Aurélie ; Neels, Antonia ; Albrecht, Martin

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...

Université de Neuchâtel

New aryl phosphinite ligands avoiding ortho-metallation: Synthesis and molecular structures of trans-[PdCl2(PPh2OR)2] and trans-[Rh(CO)Cl(PPh2OR) 2] (R = 2,4,6-Me3C6H2; 2,6-Ph2C6H3)

Chahen, Ludovic ; Karmazin-Brelot, Lydia ; Süss-Fink, Georg

In: Inorganica Chimica Acta, 2005, vol. 358, no. 12, p. 3417-3422

The new aryl phosphinites PPh2OR (R = 2,4,6-Me3C6H2, 1; R = 2,6-Ph2C6H3, 2) have been prepared from chlorodiphenylphosphine and the corresponding phenols. In these ligands, the ortho-positions of the aromatic phosphite function are blocked by methyl and phenyl substituents, which allows coordination to metal...

Université de Fribourg

Palladium complexes comprising C(4)-bound diimidazolylidene carbenes

Heckenroth, Marion ; Albrecht, Martin

In: Chimia, 2008, vol. 62, no. 4, p. 253-255

Imidazolium-derived palladium dicarbene complexes have been synthesized which feature either normal C(2) carbene bonding or abnormal C(4) bonding. Comparison of the reactivity of these complexes, in particular towards Lewis acids (H⁺, Ag⁺), indicate consistently that C(4)-bound carbenes are stronger donors than their C(2)-bound analogs. As a consequence of this electronic impact, palladium...