Structure of the Diamine−Rh(I) Precursor in the Asymmetric Hydride Transfer Reduction of Ketones: A Theoretical and Experimental Approach
Structure of the Diamine−Rh(I) Precursor in the Asymmetric Hydride Transfer Reduction of Ketones: A Theoretical and Experimental Approach
复制标题
酮不对称氢化物转移还原中二胺−Rh(I) 前体的结构：理论和实验方法
DOI：
10.1021/ja972988b
复制
发表时间：
1998
影响因子：
15
通讯作者：
M. Lemaire
中科院分区：
文献类型：
--
作者：
M. Bernard;Vincent Guiral;F. Delbecq;F. Fache;‡. A. Philippe Sautet;M. Lemaire
Rh−二胺前体在羰基化合物的不对称氢化物转移还原催化循环中的性质通过理论和实验方法进行了研究。一方面，基于密度泛函理论对三角双锥（TBP）和四方锥（SP）形式的各种[RhH（NH3）n（C2 H4）4-n]配合物进行了计算。它们的几何形状已经完全优化，并且发现唯一稳定的络合物对应于TBP形式的n = 2，其中乙烯在赤道平面上。另一方面，所合成的配合物的质量分析表明，它们的组成为[Rh（COD）（diamine）]+ X-（X- = Cl-或PF 6-）。进行了几个实验来研究配体化学计量、二烯（环辛烯（COD）或其他）的性质的影响。最后，这两种方法收敛并证明了活性物种仅包含一个二胺和一个二烯键合到金属上。
The nature of the Rh−diamine precursor in the catalytic cycle of the asymmetric hydride transfer reduction of carbonyl compounds was examined by both theoretical and experimental approaches. On the one hand, calculations based on the DFT theory were performed on various [RhH(NH3)n(C2H4)4-n] complexes, in the trigonal bipyramidal (TBP) and square pyramidal (SP) forms. Their geometry has been fully optimized, and it was found that the only stable complex corresponds to n = 2 in a TBP form, with the ethylenes in the equatorial plane. On the other hand, mass analyses of the synthesized complexes showed that their composition was [Rh(COD)(diamine)]+ X- (X- = Cl- or PF6-). Several experiments were performed to study the influence of the ligand stoichiometry, the nature of the diene (cyclooctadiene (COD) or others). Finally, the two methods converged and proved that the active species contains only one diamine and one diene bound to the metal.