163494-79-9Relevant academic research and scientific papers
Steric Control of Oxidative Trimerization of Alkynyl Ligands in Trimethylphosphane Palladium Complexes
Klein, Hans-Friedrich,Zettel, Bernd D.
, p. 343 - 350 (2007/10/02)
Alkynylpalladium compounds trans-PdX(CC-R)(PMe3)2 and trans-PdX(CC-R)(PBu3)2 as well as trans-PdX(CC-R)(PPh3)2 are prepared by known methods.Thermal decomposition between 120 and 160 deg C results in a selective transformation only with trimethylphosphane complexes 1, 2, 10-13, and 19.Oxidative trimerization of the alkynyl groups CC-CMe2R' and CC-(c-Hex) affording the enediynyl compounds trans-PdX(PMe3)2 and trans-PdX=C(c-Hex)>(PMe3)2 appears to be controlled by balanced steric demands of phoshorus and alkynyl substituents.The steric control is investigated by melting transformable monoalkynyl complex trans-PdI(CC-CMe2OH)(PMe3)2 (11) with non-transformable complex trans-PdI(PMe3)2 (20) to give a mixture (A) of transformed complexes with mixed substituents R.Similar results are obtained in other mixtures, when transformable PdBr(CC-SiMe3)(PMe3)2 is heated with the non transformabel complexes PdBr(PMe3)2 (12) with non-transformable PdBr(PMe3)2 (mixture C). - Key Words: Alkynes/ Palladium complexes/ Phosphane ligands
