Yongxin Li, K. Ng, S. Selvaratnam
Jan 18, 2003
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0
Influential Citations
27
Citations
Journal
Organometallics
Abstract
A series of enantiomerically pure organopalladium complexes containing the resolved ortho-metalated (R/S)-N,N-dimethyl-1-(9-phenanthryl)ethylamine ligand have been prepared. The absolute ring conformations of these novel organometallic phenanthrylamine chelates in the solid state and in solution have been investigated by X-ray structural analyses and 2D ROESY NMR spectroscopy, respectively. All the chiral ortho-metalated rings were found to be stereochemically rigid, with their absolute ring conformations being locked by the repulsive interactions between the methyl group on the chiral carbon and the adjacent aromatic proton H8 of the phenanthrylamine ring. The methyl substituents on the stereogenic carbons invariably take up the axial positions in the skewed five-membered rings such that the static δ and λ ring conformations are adopted by the R- and S-phenanthrylamine, respectively. Despite the enormous interchelate steric constraints, the monodentates PPh3 and DMPP are coordinated regiospecially to the...