Design, Preparation and Characterization of the Adducts of the Bis‐Amido Cobalticinium Complex [CoIII(η5‐C5H4CONHC5H4N)2][PF6] with Fumaric and Maleic Acids

Abstract

AbstractThe supramolecular hydrogen‐bonded adducts obtained by treating the cationic bis‐amido complex [CoIII(η5‐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 supramolecular salts containing either the dication [CoIII(η5‐C5H4CONHC5H4N)(η5‐C5H4CONHC5H4NH)]2+, [1H]2+, or the trication [CoIII(η5‐C5H4CONHC5H4NH)2]3+, [1H2]3+. The derivatives of the reaction with fumaric acid, namely, [CoIII(η5‐C5H4CONHC5H4N)(η5‐C5H4CONHC5H4NH)]2+·[PF6]–·1/2[fumarate]2–, [1H]2+·PF6–·1/2[fumarate]2–, and [CoIII(η5‐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 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(η5‐C5H4CONHC5H4N)(η5‐C5H4CONHC5H4NH)]2+·5/2[PF6]–·3/2[Hmaleate]–, 2[1H]2+·5/2[PF6]–·3/2[Hmaleate]–, 2[CoIII(η5‐C5H4CONHC5H4NH)2]3+·3[PF6]–·3[Hmaleate]–·2H2O, 2[1H2]3+·3[PF6]–·3[Hmaleate]–·2H2O and [CoIII(η5‐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. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)