Complexes of amine cations with lasalocid A,a microbial ionophore

Complexes having the stoichiometry [R-NH₃⁺][lasalocid A^-] have been prepared and characterized, where R represents a series of organic substituents with diverse steric and electronic properties. The crystalline complexes dissolve readily in solvents of low polarity such as chloroform and are characterized in this solvent by molecular weight data and ¹³C nmr spectroscopy. NMR data indicate that the cations bind the lasalocid A anion $\text{via}$ hydrogen bonds to O₃, O₆, and O₈. Molecular weight data show that none of these complexes are appreciably dissociated in chloroform solution.