Studies of Ethylenediamine-N,N′-diacetatocobalt(III) Complexes. The Preparation and Identification of Ethylenediamine-N,N′-diacetatocobalt(III) Complexes with Ammonia, Pyridine, or Alkylamines as the Additional Ligand

A group of cobalt(III) complexes containing the tetradentate ethylenediamine-N,N′-diacetate anion (EDDA) and ammonia, pyridine, or alkylamines have been derived from ethylenediamine-N,N′-diacetato(diaquo)cobalt-(III) perchlorate. Three different series among the complexes—(1) the aquo(amine) series, [Co(EDDA)(H2O)-(am)]ClO4, (2) the α-cis-bis(amine) series, α-cis-[Co(EDDA)(am)2]ClO4, and (3) β-cis-[Co(EDDA)(NH3)2]ClO4 as well as β-cis-[Co(EDDA)(en)]ClO4, have been obtained, depending on the conditions of the reaction between the starting diaquo complex and the amines. Some properties of the complexes have been examined, and the geometrical configuration of each complex has been identified on the basis of the electronic absorption spectra and the proton NMR spectra. The coordination tendency of EDDA and the amines have also been discussed.