
TY  - JOUR
A1  - Woon, T 
A1  - O'Conner, MJ 
T1  - Cobalt(III) Complexes of a Stereospecific Ligand Derived from (S)-Proline
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1979
VL  - 32
IS  - 8
SP  - 1661
EP  - 1667
KW  - 
UR  - https://doi.org/10.1071/CH9791661 
N2  - The quadridentate ligand, (2S,2'S)-1,1'-(ethane-1,2-diyl)bis(pyrrolidine-2-carboxylic acid) dihydrochloride (H2pren,2HCl), has been derived from (S)-proline. The preparations of the cobalt(III) complexes Na [Co(pren)(CO3)],3H2O, [CO(pren)(H2O)2] ClO4,- 2H2O and [Co(pren)(H2O)Cl],1·5H2O are described. All exist as cis-&#945; geometrical isomers. 13C N.M.R. and absorption spectral measurements confirm the cis-&#945; arrangement. The complex cis-&#945;- [Co(pren)(H2O)Cl],1·5H2O rapidly aquates with retention of configuration. The compounds having actual or near C2 symmetry exhibit a strong negative c.d. band under the 1A1g &#8594; 1T1g cubic absorption band which is due to the 1A1 &#8594;1E tetragonal component, consistent with the &#916; absolute configuration imposed by the (S) configuration of the asymmetric carbon atom in the (S)-proline moiety. The o.r.d. spectrum of cis-&#945;-Na [Co(pren)CO3],3H2O in aqueous solution has a negative Cotton effect at low energy as expected for the &#916; absolute configuration. 
ER  -

