The Crystal Structure of an Inclusion Complex of Benzyltrimethylammonium Bromide with (R)-(+)-1,1′-binaphthalene-2,2′-diol

Abstract

The donor-acceptor interactions in a complex have attracted attention from the viewpoint of their effect on its novel functional molecular properties.1 The donor-acceptor interactions have also attracted considerable attention in the field of supramolecular chemistry as intermolecular forces can construct and control supramolecular structure.2 One of our group’s aims is to assemble supramolecular solid materials where directionality, and the possibility of controlling the strength of the interactions, are influenced by the arrangement of nonplanar organic molecules (typically, racemic and chiral molecules) with functional groups that can interact with groups in an arylammonium salt through strong and weak H-bonds, as well as other noncovalent interactions, since such studies have not been well considered as per revealed by our search of Cambridge Structure Database version 5.34 2013, and may also contribute to knowledge in separation science and crystal engineering. Recently, we have reported the formation of crystal complex involving rac-1,1′-binaphthalene-2,2′-diol (hereafter, BNP) with benzyltrimethylammonium chloride (hereafter, BTMAC) in which the phenyl group in the arylammonium salt controlled the directionality of the methyl groups to generating weak H-bonds that played relevant roles in crystal complexation, stabilizing the crystal structure, as well as enhancing the molecular recognition phenomenon in the supramolecular structure. Thus, we found it prudent to investigate the structure of the benzyltrimethylammonium bromide (hereafter, BTMAB) complex with (R)-(+)-1,1′binaphthalene-2,2′-diol (hereafter, RBNP) in order to know the effect of changing from the chloride (Cl–) to bromide (Br–) in the arylammonium salt, as well as altering from racemic to (R) form of (+)-1,1′-binaphthalene-2,2′-diol on such a supramolecular system with respect to knowing the packing structure, and interactions in the molecular recognition phenomenon that may exist in the BTMAB/RBNP complex. Gratifyingly, we have solved the crystal structure, analyzed and discussed herein. Single crystals of the BTMAB/RBNP complex were obtained from a solvent mixture of a warmed acetone/ethylacetate (20 mL) mixture in which BTMAB (0.23 g, 1 mmol), and RBNP (0.29 g, 1 mmol) were dissolved, and allowed to evaporate slowly at room temperature, and characterized through X-ray diffraction at 150 K. Crystal data and data collection details are listed in Table 1. Data collection and cell refinement were carried out using DENZO-SMN. Structure solution was carried out with direct methods using the programs SIR 92 within the CRYSTALS software suite, and refined by full-matrix least-squares methods based on F2. The H atoms were included 2021 © The Japan Society for Analytical Chemistry