STEREOSELECTIVITY ON ELECTRON-TRANSFER REACTIONS .1. REACTION OF THE LAMBDA-[CO(EDDS)](-) AND RAC-[CO(DIAMINE)(3)](2+) COMPLEXES (DIAMINE EQUALS EN, CHXN)

The absolute configuration of an optically active Lambda-[Co(EDDS)](-) (EDDS = ethylene-diaminedisuccinate) complex was determined as Lambda by the regional rule and spectroscopic data. The stereoselective ioni c association between Lambda-[Co(EDDS)](-) and rac-[Co(en)(3)](3+) occ urs preferentially between Lambda-[Co(EDDS)](-) and Delta-[Co(en)(3)]( 3+). The stereoselective electron transfer reaction between Delta-[Co( EDDS)](-) and rac-[Co(en)(3)](2+) has been investigated in aqueous sol ution, DMF and DMSO. Their enantiomeric excesses (e.e.) observed are 1 4%, 26% and 40% of Delta-[Co(en)(3)](3+), respectively. The electron t ransfer reaction between Lambda-[Co(EDDS)](-) and conformationally res tricted [Co(chxn)(3)](2+) has been examined in aqueous and DMSO soluti on. In aqueous solution, there are four isomers in the product which w ere determined as lel(3), lel(2)ob, lelob(2), and ob(3) of Delta-[Co(c hxn)(3)](3+) with optical purities of 22%, 25%, 11% and 10% e.e. respe ctively. In DMSO, the reaction produces lel(3)-Delta- and lel(2)ob-Del ta-[Co(chxn)(3)](3+) with optical purities of 100% and 75% e.e. respec tively.