Design, preparation and characterization of the adducts of the bis-amido cobalticinium complex [CoIII(η5-C5H4CONHC5H4N)2][PF6] with fumaric and maleic acids

The supramolecular hydrogen-bonded adducts obtained by treating the cationic bis-amido complex [Co-III(eta(5-)C(5)H(4)CONHC(5)H(4)N)(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 supramolecular salts containing either the dication [Co-III(eta(5)-C5H4CONHC5H4N)(eta(5)-C5H4CONHC5H4NH)](2+), [1H](2+), or the trication [Co-III(eta(5)-C5H4CONHC5H4NH)(2)](3+), [1H(2)](3+). The derivatives of the reaction with fumaric acid, namely, [Co-III(eta(5)-C5H4CONHC5H4N)(eta(5)-C5H4CONHC5H4NH)](2+)center dot[PF6](-)center dot 1/2[fumarate](2-), [1H](2+)center dot PF(6)(-)center dot 1/2[fumarate](2-), and [Co-III(eta(5)-C5H4CONHC5H4NH)(2)](3+)center dot[PF6](-)center dot[H(fumarate)(2)](3-)center dot H(3)O(+)center dot H2O, [1H(2)](3+)center dot[PF6](-)center dot[H(fumarate)(2)](3-)center dot H(3)O(+)center dot H2O, contain either the dianion [fumarate](2-) or the hydrogen-bridged supramolecular 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 intramolecular hydrogen-bond formation generates exclusively salts of the hydrogen maleate anions, namely, [COIII(eta(5)-C5H4CONHC5H4N)(eta(5)-C5H4CONHC5H4NH)](2+)center dot 5/2[PF6](-)center dot 3/2[Hmaleate](-), 2[1H](2-)center dot 5/2[PF6](-)center dot 3/2[Hmaleate](-), 2[Co-III(eta(5)-C5H4CONHC5H4NH)(2)](3-)center dot 3[PF6](-)center dot 3[Hmaleate](-)center dot 2H(2)O, 2[1H(2)](3+)center dot 3[PF6](-)center dot 3[Hmaleate](-)center dot 2H(2)O and [Co-III(eta(5)-C5H4CONHC5H4NH)(2)](3+)center dot 2[PF6](-)center dot[Hmaleate](-)center dot H2O, [1H(2)](3+)center dot 2[PF6](-)center dot[Hmaleate]center dot H2O, in which the hydrogen maleate anions act as bridges between the protonated bis-amido organometallic sandwiches. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005).