Synthesis of nitrogen mustards on cobalt(iii)

Abstract

Bis(bidentate) and bis(tridentate) Co(III) complexes of N-(2-hydroxyethyl)ethane-1,2-diamine (heen), 2-[(2-aminoethyl)amino]ethan-1-olate (heen-H), or N-(2-chloroethyl)ethane-1,2-diamine (ceen) ligands have been synthesised, and a range of reaction conditions established for their syntheses by different routes. They can all be ultimately derived from (OC-6-12′)-[Co(heen)₂(NO₂)₂]NO₃ and provide access to the trans amine trans chloride nitrogen mustard complex, (OC-6-12′)-[Co(ceen)₂(Cl)₂]Cl. Although complex isomeric mixtures were obtained from the reaction of (OC-6-12′)-[Co(heen)₂(NO₂)₂]NO₃ under different reaction conditions, ultimately, the trans amine trans chlorido configuration around the Co(III) metal centre of the (OC-6-12′)-[Co(ceen)₂(Cl)₂]Cl complex was favoured.