Formation and Structure of a Platinum(II) Complex Containing Two trans Nonstabilized Phosphorus Ylide Ligands: Evidence for Reversible Ylide Dissociation
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- 作者：Pavel A. Dub ; Aur茅lien B茅thegnies ; Jean-Claude Daran ; Rinaldo Poli
- 刊名：Organometallics
- 出版年：2012
- 出版时间：April 23, 2012
- 年：2012
- 卷：31
- 期：8
- 页码：3081-3086
- 全文大小：292K
- 年卷期：v.31,no.8(April 23, 2012)
- ISSN：1520-6041
文摘
The reaction of (nBu4P)2[PtBr4] with 2,2鈥?(C6H4Li)2 yields selectively (by 195Pt and 31P NMR) the compound trans-PtBr2[CH(nPr)(PnBu3)]2 as a mixture of meso (R,S) and dl (R,R + S,S) diastereoisomers. The initially formed 1:1 mixture slowly evolves toward a solution richer in the meso compound, which then crystallizes selectively. In addition to the NMR characterization, the meso isomer has also been characterized by a single-crystal X-ray diffraction analysis. DFT calculations in the gas phase and in solution (THF) confirm the slight thermodynamic preference for the meso isomer and reproduce the chemical shift difference of the 195Pt NMR resonances. They also suggest the likelihood of a dissociative mechanism for the slow diastereoisomer interconversion.