Solid-State Structure of a Layered Hydrogen-Bonded Salt: Guanidinium 5-Benzoyl-4-hydroxy-2-methoxybenzenesulfonate Methanol Solvate

Guanidinium 5-benzoyl-4-hydroxy-2-methoxybenzene-sulfonate methanol solvate [C(NH₂)₃+.(C₁₄H₁₁O ₃)SO3^-.-CH₃OH] crystallizes into a layered structure containing a two-dimensional hydrogen-bonded network typical of guanidinium alkane- and arenesulfonates. All six guanidinium protons and six sulfonate oxygen lone-pair acceptors participate in hydrogen bonding to form nearly planar pseudohexagonal hydrogen-bonded sheets, which can be viewed as parallel connected hydrogen-bonded ribbons. The 5-benzoyl-4-hydroxy-2-methoxybenzene groups are oriented to the same side of each ribbon, but the orientation of these groups on adjacent ribbons alternates with respect to the hydrogen-bonded sheet. The planar sheets stack with interdigitation of the arene groups, resulting in a structure in which layers of 5-benzoyl-4-hydroxy-2-methoxybenzene groups are separated by ionic hydrogen-bonded sheets. Each methanol molecule forms a hydrogen bond to one of the sulfonate O atoms, resulting in this oxygen forming a total of three hydrogen bonds, and fills void volume between the interdigitated 5-benzoyl-4-hydroxy-2-methoxybenzene groups of neighboring sheets. The benzophenone hydroxyl proton forms an intramolecular hydrogen bond to the carbonyl oxygen.