Isomers of the bis(diethylenetriamine)cobalt(III) ion and a new source of optical activity

The three geometric isomers of the [Co(dien)₂]⁸⁺ ion s-cis, u-cis, and trans have been separated by various methods, and the u-cis and trans isomers have been resolved into optical isomers through diastereoisomer formation. The configurations have been unequivocally assigned to these geometric forms from the different racemization behavior of the u-cis and trans optical isomers. Factors determining relative isomer stabilities are discussed, and infrared and pmr criteria for assigning isomer configurations are examined.