CHIRAL DISCRIMINATION IN THE REDUCTION OF [CO(EDTA)](-) BY [CO(EN)(3)](2- X-RAY STRUCTURE OF O(EN)(3)][DELTA-CO(EDTA)]CL-2-CENTER-DOT-10H(2)O() AND [RU(EN)(3)](2+) )
Rml. Warren et al., CHIRAL DISCRIMINATION IN THE REDUCTION OF [CO(EDTA)](-) BY [CO(EN)(3)](2- X-RAY STRUCTURE OF O(EN)(3)][DELTA-CO(EDTA)]CL-2-CENTER-DOT-10H(2)O() AND [RU(EN)(3)](2+) ), Inorganic chemistry, 33(2), 1994, pp. 227-232
The structure of the salt [Lambda-Co(en)(3)][Delta-Co(edta)]Cl-2.10H(2
)O has been determined by X-ray crystallography. The salt crystallizes
in the orthorhombic space group P2(1)2(1)2 (No. 18) with Z = 2, a = 2
1.046(3) Angstrom, b = 12.813(2) Angstrom, c = 8.158(1) Angstrom, and
R = 0.035 fbr 5263 reflections. The complex ions participate in a netw
ork of hydrogen bonds which is interpreted to suggest a mechanism for
chiral discrimination. Outer-sphere reduction of [Co(edta)](-) by [Ru(
en)(3)](2+) takes place with a second-order rate constant of 6 x 10(3)
M(-1) s(-1) at 25 degrees C and 0.10 M ionic strength. Chiral inducti
on in the reaction results in a 2% enantiomeric excess with a Delta La
mbda preference, significantly smaller than the 10% Delta Lambda induc
tion found with [Co(en)(3)](2+) as reductant. This difference in chira
l induction between the two reductants is ascribed to differences in c
hiral recognition in the assembly of electron-transfer precursor compl
exes.