Synthesis, Characterization, and Solution Behavior of Optically Active cis Organocobalt Salen Complexes with
详细信息 查看全文
- 作者：Renata Dreos ; Giorgio Nardin ; Lucio Randaccio ; Patrizia Siega ; and Giovanni Tauzher
- 刊名：Inorganic Chemistry
- 出版年：2004
- 出版时间：May 31, 2004
- 年：2004
- 卷：43
- 期：11
- 页码：3433 - 3440
- 全文大小：173K
- 年卷期：v.43,no.11(May 31, 2004)
- ISSN：1520-510X
文摘
The reaction of a cis 
folded organocobalt derivative with a salen-type ligand, 1, isolated as racemic compoundof 
and 
enantiomers, with enantiomerically pure 
-L amino acids is reported. The reaction between racemic1 and L-tyrosine afforded a mixture of the two diastereoisomers -2 and -2, which could be separated by fractionalcrystallization owing to the lower solubility of -2. The absolute configuration of the two diastereomers wasunequivocally assigned from the X-ray structure, using the known absolute configuration of the asymmetric carbonof the amino acid as internal reference. The reaction of racemic 1 with trans-4-hydroxy-L-proline afforded only thediastereoisomer with a configuration of the tetradentate ligand, as proved by X-ray diffractometric analysis. Forboth L-tyrosine and trans-4-hydroxy-L-proline, the amino acid initially coordinates both to the and to the enantiomers of 1, leading to an about equimolar mixture of diastereoisomers. In the case of L-tyrosine thediastereoisomers have about the same energy, so that the successive isomerization is negligible. In the case oftrans-4-hydroxy-L-proline, -3 is much more stable than -3, and the isomerization reaction -3 
-3 goespractically to completion.
folded organocobalt derivative with a salen-type ligand, 1, isolated as racemic compoundof and enantiomers, with enantiomerically pure -L amino acids is reported. The reaction between racemic1 and L-tyrosine afforded a mixture of the two diastereoisomers -2 and -2, which could be separated by fractionalcrystallization owing to the lower solubility of -2. The absolute configuration of the two diastereomers wasunequivocally assigned from the X-ray structure, using the known absolute configuration of the asymmetric carbonof the amino acid as internal reference. The reaction of racemic 1 with trans-4-hydroxy-L-proline afforded only thediastereoisomer with a configuration of the tetradentate ligand, as proved by X-ray diffractometric analysis. Forboth L-tyrosine and trans-4-hydroxy-L-proline, the amino acid initially coordinates both to the and to the enantiomers of 1, leading to an about equimolar mixture of diastereoisomers. In the case of L-tyrosine thediastereoisomers have about the same energy, so that the successive isomerization is negligible. In the case oftrans-4-hydroxy-L-proline, -3 is much more stable than -3, and the isomerization reaction -3 -3 goespractically to completion.