Chiral discrimination in lithium complexes of bis(5H-pyrroles) and bis(oxazolines)
Ibon Alkorta1, Oscar Picazo, José Elguero
1Instituto de Química Médica (CSIC), Juan de la Cierva 3, 28006-Madrid, Spain. ibon@iqm.csic.es
Abstract:
The 1:1 and 2:1 complexes of chiral bis(5H-pyrroles) and bis(oxazolines) with the lithium cation have been studied by means of DFT methods (B3LYP/6-31G and B3LYP/6-311+G). The energetic, geometric, electronic, and orbital properties of the complexes have been analyzed. The chiral discrimination in the 2:1 complexes (homo vs heterochiral ones) indicate that in all the cases the heterochiral complexes are more stable than the homochiral ones, except for the tert-butyl derivatives. The chiral discrimination energies will be discussed on the basis of different parameters related to the lithium atom such as the N-Li distance, the orbital interaction between the lone pair of the nitrogen and an empty orbital of the lithium, and its atomic contribution to the total energy of the complexes.
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