Hydrogen-bonded metallosupramolecular helices composed of a nona-protonated spherical RhIII4ZnII4 cluster with twelve carboxylate arms

Treatment of an octanuclear RhIII4ZnII4 cluster containing 12 free carboxylate groups, K6[Rh4Zn4O(L-cys)12] (K6[1], L-H2cys = L-cysteine), with inorganic acids (HX = HBr, H2SO4) produced ionic crystals of [H91]X3 composed of nona-protonated [H91]3+ cations and X anions. The H-bonded metallosupramolecular helices in [H91]X3, which showed proton conductivity and ammonia adsorption, were controlled by the employed inorganic anions.