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 P2 1 2 1 2 1. 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 (CyNH 3) and sulfanilate (NH 2 PhSO 3 À) are both low-cost achiral building units. A statistical investigation of previously reported structures shows that NH 2 PhSO 3 À stabilized by noncentrosymmetric cations more likely lead to noncentrosymmetric materials.

Dipropylammonium 4-aminobenzenesulfonate

“…The cation adopts an extended structure with a minimum torsion angle of 174.7 (4) for N2-C10-C11-C12. The involvement of the oxygen atoms of the sulfonate group in the anion as hydrogenbond acceptors is manifested in a slight difference in the S-O bond lengths [S1-O1 = 1.446 (2), S1-O2 = 1.454 (2), S1-O3 = 1.449 (2) Å ]: these data are consistent with those in sulfanilate anions previously reported (Sarr et al, 2016;Kama et al, 2019). In the extended structure, each sulfanilate anion interacts with four neighbours via simple N-HÁ Á ÁO and bifurcated N-HÁ Á Á(O,O) hydrogen bonds (Table 1) to generate (101) layers (Fig.…”

“…Some sulfanilate-based compounds have high optical non-linearity and may be candidates for applications in optoelectronics and photonics in combination with organic cations such as guanidinium (Russell et al, 1994), triethylammonium (Li et al, 2007), diisopropylammonium (Sarr et al, 2016) and cyclohexylammonium (Kama et al, 2019). As part of our ongoing studies in this area (Sarr et al, 2016), we now describe the synthesis and crystal structure of the title molecular salt, which crystallizes in the noncentrosymmetric space group Pn.…”

Solid‐state synthesis of cyclo LD‐diphenylalanine: A chiral phase built from achiral subunits

“…We can discuss these surprising results at the light of what is known on chiral supramolecular objects. These objects can first form from completely achiral subunits assembled in a chiral manner . The formed system can be a conglomerate, in the absence of perturbation or can be driven into a given chirality by a chiral influence.…”