THE STEREOCHEMISTRY AND ABSOLUTE-CONFIGURATIONS OF THE METAL-COMPLEXES OF NOVEL OPTICALLY-ACTIVE NSSN SYSTEM TETRADENTATE LIGANDS - COBALT(III) COMPLEXES OF '-BIS(BETA-AMINOETHYL)-TRANS-1,2-DITHIOCYCLOHEXANE -CRYSTAL-STRUCTURE AND MOLECULAR-STRUCTURE OF S-CIS[CO(ADCH)CL-2]CL.C2H5OH

A novel open-chain tetradentate ligand having the NSSN donor atom arra y, S,S'-bis(beta-aminoethyl) trans-1,2-dithiocyclohexane (adch), has b een synthesized and the cobalt(III) complexes of [Co(adch)X-2](+) (X = Cl-, NO2-, NCS-, X-2 = CO32-) have been prepared. Only the s-cis geom etric isomers have been formed. From the reaction between Na-3[CO(CO3) (3)] and the racemic adch ligand, the RR-adch ligand is coordinated to the cobalt(III) ion stereospecifically to give the Lambda-s-cis-(delt a lambda delta)-[Co(adch)Cl-2](+) enantiometer complex, while the SS-a dch ligand stereospecifically to give the Delta-s-cis-(lambda delta la mbda)-[Co(adch)Cl-2](+) enantiometer complex, which have been observed in the crystal structure of the [Co(adch)Cl-2]Cl-2 . C2H5OH complex s olved by single-crystal X-ray analysis. The unit cell contains both La mbda and Delta complex isomer, two chloride ions ana two ethanol molec ules. The bond distances in Angstrom: Co-S = 2.241 (2) and 2.232 (2), Co-N = 1.963 (5) and 1.959 (6), Co-Cl = 2.262 (2) and 2.250 (2). The c oordination geometry about the cobalt atom is a distorted octahedron. (C) 1997 Elsevier Science Ltd.