Atropochiral (C,C)-chelating NHC-ylide ligands: synthesis and resolution of palladium(II) complexes thereof.
Atropochiral NHC-phosphonium ylides based on the naphthyl-benzimidazolyl core are targeted as strongly sigma-donor C,C-chelating ligands of transition metals. The ligand core is shown to act in either a monodentate (through the carbene center) or bidentate (through the carbene and the ylide centers) fashion in seven palladium(ii) complexes obtained by two sequential strategies. In particular, the enantiomerically pure ortho-palladated (S)-dimethyl(1-phenylethyl)amine co-ligand is used as the chiral resolving agent for the separation of diastereoisomeric NHC-ylide complexes by fractional crystallization. Hydrochloric treatment of either diastereoisomer was found to keep intact the two carbon-palladium bonds, while affording the corresponding enantiomeric beta-zwitterionic NHC-ylide palladate complexes. The absolute configuration of the chirally isolated C,C-chelating ligand was finally confirmed by X-ray crystallography.
Abdellah
Ibrahim
I
CNRS; LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077, Toulouse, France.
Debono
Nathalie
N
Canac
Yves
Y
Duhayon
Carine
C
Chauvin
Remi
R
D002614:Chelating Agents / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006571:Heterocyclic Compounds / Q000737:chemistry*; D008024:Ligands; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism
D002614:Chelating Agents; D006571:Heterocyclic Compounds; D008024:Ligands; D009942:Organometallic Compounds; C030011:carbene; D010165:Palladium; D008697:Methane