Template synthesis of amidine- And amide-functionalised cobalt(in) hexaaza cage complexes

The reaction of [Co(sen)]Cl₃-H₂O {sen = 4, 4′, 4″-ethylidynetris(3-azabutan-l-amine)} with methanal and ethyl cyanoacetate in aqueous base led to the synthesis of three functionalised cobalt(m) cage complexes: (l-cyano-8methyl-2-oxo-3, 6, 10, 13, 16, 19-hexaazabicyclo[6.6.6]icosanato)cobalt(m) chloride-\vater( 1/3) [Co(CN, Me-2-oxosar H)]Cl2-3HjO; (2-amino-1 -carboxy-8-methyl-3, 6, 10, 13, 16, 19-hexaazabicyclo[6.6.6]icos-2-ene)cobalt(ni)]trichlorideethanol-water(l/0.5/3. 5), [Co(Me, CO2H-2-aminosar-2-ene)]Cl3-0.5C2H5OH-3.5H2O; and (2-amino-8-methyl3, 6, 10, 13, 16, 19-hexaazabicyclo[6.6.6]icos-2-ene)cobalt(ni) trichloride-water( 1/3), [Co(Me-2-aminosar-2-ene)]Cl33H₂O. The amidine-functionalised cages are the first hexaaza cages ofthat type. The structure of [Co(CN, Me-2oxosar -H)[C₄OjnCl-HjO has been established by X-ray crystallographic analysis. The syntheses, chemical reactions and spectroscopic and electrochemical properties of the cage complexes are described.