Hydrogen bonds within an ionic environment: The remarkable behavior of thezwitterion [Co-III(eta(C5H4COOH)-C-5)(eta(5)-C5H4COO)]

The organometallic zwitterion [Co-III(eta(5)-C5H4COOH)(eta(5)-C5H4COO)] for ms a hydrogen-bonded supramolecular adduct with the cationic acid [Co-III(e ta(5)-C5H4COOH)(2)](+) in the solid state and shows self-organization aroun d K+ cations in the mixed system {[Co-III(eta(5)-C5H4COOH)(eta(5)-C5H4COO)] (2)}[K](+)[PF6](-).(eta(5)-C5H4COOH)(2)](+) (see Chart 1).(9) In the follow ing we shall discuss self-assembly and HE interactions in crystalline [Co-I II(eta(5)-C5H4COOH)(2)](+)[PF6](-) (1) and in the cocrystalline salt of the zwitterionic form [Co-III(eta(5)-C5H4COOH)(eta(5)-C5H4COO)] (see Chart 1), namely {[Co-III(eta(5)-C5H4COOH)(eta(5)-C5H4COO)][Co-III(eta(5)-C5H4COOH)( 2)]}(+)[PF6](-) (2). Finally, we will discuss the intriguing interactions b etween zwitterions and K+ cations in {[Co-III(eta(5)-C5H4COOH)(eta(5)-C5H4C OO)](2)}[K](+)[PF6](-) (3).(10).