Cyclohexylammonium sulfanilate: A simple representative of the chiral materials containing only achiral building units

Abstract

Chiral building units must pack into chiral crystal structures. However, chiral structures can also be induced from achiral building units. In this letter, the later well-known phenomenon is illustrated with the simple synthesis of a new chiral compound from commonly used achiral organic molecules. Thus, the new compound cyclohexylammonium sulfanilate was synthesized at room temperature and characterized by single crystal X-ray diffraction, spectroscopy (UV/Visible and FT-IR), and thermal analysis. The compound is chiral and crystallizes in orthorhombic system with space group P212121. Noncentrosymmetry was confirmed by Second Harmonic Generation (SHG) measurements using solid potassium dihydrogenphosphate (KDP) as reference. The organic ions which form this chiral compound namely cyclohexylammonium (CyNH3+) and sulfanilate (NH2PhSO3−) are both low-cost achiral building units. A statistical investigation of previously reported structures shows that NH2PhSO3− stabilized by noncentrosymmetric cations more likely lead to noncentrosymmetric materials.