Search

The orthometalated [1-(dimethylamino)ethyl]naphthalene platinum(II) complex has been used successfully to promote the asymmetric cycloaddition reaction between 3,4-dimethyl-1-phenylphosphole and sulfoxide in high selectivity. The exo-cycloadduct coordinated to the platinum template as bidentate chelates via their phosphorus and sulfur atoms. The dichloro platinum complexes could be crystallized and were stable in the solid state as well as in solution. Optically pure P–S bidentate ligands could be liberated from these dichloro complexes by treatment with aqueous potassium cyanide. The study also highlights the difference in reactivity and mode of substrate activation between an earlier study involving a Pd analogue of the template and the current results.

The organopalladium complex containing ortho-metalated (S)-[1-(dimethylamino)ethyl]naphthalene as the chiral auxiliary has been used successfully to promote the asymmetric cycloaddition reaction between 3,4-dimethyl-1-phenylarsole and diphenylvinylphosphine oxide in high stereoselectivity (only one isomer). However, the neutral dichloro palladium complex obtained upon removal of the auxiliary is very unstable and instantly decomposed to produce the arsenic elimination reaction product (3,4-dimethyl-2,4-cyclohexadienyl)diphenylphosphine oxide. However when the same reaction was promoted by the analogous platinum complex, only one stereoisomer was again obtained, but the resulting dichloro platinum complex is very stable in the solid state as well as in solution and coordinates to the platinum center as a As−O bidentate ligand, as confirmed by 1H NMR and single-crystal X-ray analysis. The enantiomerically pure As P═O hetero-bidentate ligand could be readily liberated from the dichloro platinum complex as a...

A series of amine bis(phenolato)lanthanide methyl and amido complexes were synthesized by general salt metathesis reaction in this paper. The reaction of anhydrous lanthanide trichlorides with 1 equiv of sodium amine bis(phenolate) LNa2 [L = Me2NCH2CH2N{CH2-(2-O-C6H2-But2-3,5)}2] in THF at room temperature gave the amine bis(phenolate) lanthanide chlorides LLnCl(THF) (Ln = Yb (1), Ln = Er (2)). Complexes 1 and 2 can be used as starting materials to prepare amine bis(phenolate) lanthanide derivatives. Complexes 1 and 2 reacted with lithium methyl and lithium amide, respectively, to give the corresponding lanthanide methyl and amido products LLnMe(THF) (Ln = Yb (3), Ln = Er (4)) and LLnNPh2(THF) (Ln = Yb (5), Ln = Er (6)). These complexes were well characterized by elemental analyses and IR spectra. The definitive molecular structures of complexes 1, 2, 3, 5, and 6 were provided by single-crystal X-ray analyses. Reactivity studies of complexes 3, 5, and 6 have shown them to be efficient initiators for the r...