Structural aspects of the protonation of small cages. Preparation of the new aza-cage 12,17-dimethyl-1,9,12,17-tetra-azabicyclo[7.5.5]nonadecane (L). Thermodynamic studies on solution equilibria. Crystal structures of [H2L][CoCl4] and [H2L1][CoCl4] salts | Publicación