Template synthesis of amidine- and amide-functionalised cobalt(III) hexaaza cage complexes

The reaction of [Co(sen)]Cl-3. H2O {sen=4,4',4"-ethylidynetris(3-azabutan-1-amine)} with methanal and ethyl cyanoacetate in aqueous base led to the synthesis of three functionalised cobalt(III) cage complexes: (1-cyano-8-methyl-2-oxo-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosanato)cobalt(III) chloride-water(1/3) [Co(CN,Me-2-oxosar-H)]Cl-2. 3H(2)O; (2-amino-1-carboxy-8-methyl-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icos-2-ene)cobalt(III)]trichloride-ethanol-water(1/0.5/3.5), [Co(Me,CO2H-2-aminosar-2-ene)]Cl-3. 0.5C(2)H(5)OH . 3.5H(2)O; and (2-amino-8-methyl-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icos-2-ene)cobalt(III) trichloride-water(1/3), [Co(Me-2-aminosar-2-ene)]Cl-3. 3H(2)O. The amidine-functionalised cages are the first hexaaza cages of that type. The structure of [Co(CN,Me-2- oxosar-H)][ClO4](3/2)Cl-1/2. H2O has been established by X-ray crystallographic analysis. The syntheses, chemical reactions and spectroscopic and electrochemical properties of the cage complexes are described.