Design, preparation and characterization of the adducts of the bis-amido cobalticinium complex [CoIII(h5-C5H4CONHC5H4N) 2][PF6] with fumaric and maleic acids.

The supramol. hydrogen-bonded adducts obtained by treating the cationic bis-amido complex [CoIII(h5-C5H4CONHC5H4N)2]+ with fumaric and maleic acid are investigated and their modes of aggregation in the solid state are explored. It is shown that the bis-amido organometallic complex can be mono- and di-protonated in the reaction with the dicarboxylic acids, leading to the formation of complex, mixed-anion supramol. salts contg. either the dication [CoIII(h5-C5H4CONHC5H4N)(h5-C5H4CONHC5H4NH)]2+, [1H]2+, or the trication [CoIII(h5-C5H4CONHC5H4NH)2]3+, [1H2]3+. The derivs. of the reaction with fumaric acid, namely, [CoIII(h5-C5H4CONHC5H4N)(h5-C5H4CONHC5H4NH)]2+.[PF6]-.1/2[fumarate]2-, [1H]2+.PF6-.1/2[fumarate]2-, and [CoIII(h5-C5H4CONHC5H4NH)2]3+.[PF6]-.[H(fumarate)2]3-.H3O+.H2O, [1H2]3+.[PF6]-.[H(fumarate)2 ]3-.H3O+.H2O, contain either the dianion [fumarate]2- or the hydrogen-bridged supramol. trianion [H(fumarate)2]3-, depending on the amide/acid stoichiometric ratio. In the case of maleic acid, on the other hand, the possibility of intramol. hydrogen-bond formation generates exclusively salts of the hydrogen maleate anions, namely, [CoIII(h5-C5H4CONHC5H4N)(h5-C5H4CONHC5H4NH)]2+.5/2[PF6]-.3/2[Hmaleate]-, 2[1H]2+.5/2[PF6]-.3/2[Hmaleate]-, 2[CoIII(h5-C5H4CONHC5H4NH)2]3+.3[PF6]-.3[Hmaleate]-.2H2O, 2[1H2]3+.3[PF6]-.3[Hmaleate]-.2H2O and [CoIII(h5-C5H4CONHC5H4NH)2]3+.2[PF6]-.[Hmaleate]-.H2O, [1H2]3+.2[PF6]-.[Hmaleate]-.H2O, in which the hydrogen maleate anions act as bridges between the protonated bis-amido organometallic sandwiches.