Hybrid interaction network of guanidinium–biphenyldisulfonic acid for the structure determination of liquid molecules

Abstract

Guanidinium−biphenyldisulfonic acid (GBPS) was used as a coformer for the co-crystallization of liquid compounds 1-8 [isoeugenol (1), (-)-isopulegeol (2), eugenol acetate (3), trans-anethole (4), p-anisaldehyde (5), methyl isoeugenol (6), 2,6-dimethylaniline...

Structure determination of liquid molecules by encapsulation in an aromatic cavity with hydrogen bonding and enhanced C–H⋯π interactions

“…Next, we studied the host–guest properties of 2 , 3 and 4 with GNPS, which had never been crystallized with GBPS as the coformer. 18…”

“…5-c2) were observed between the corresponding liquid molecules and naphthalenedisulfonic acid moiety of GNPS, which shows more C–H⋯π interactions or shorter distances than the corresponding host–guest complexes with GBPS [2.98(0) and 2.70(0) Å in GBPS⊃ 2 , no C–H⋯π interaction in GBPS⊃ 3 , and only 2.79(1) Å in GBPS⊃ 4 ]. 18 Furthermore, the liquid molecule 3 forms a π⋯π interaction with the naphthalenedisulfonic acid moiety with a face to face distance of 3.50 Å in the crystal structure of GNPS⊃ 3 (Fig. S3b†).…”

“…Compared to the previous structure of GBPS⊃ 1 , the structures and absolute configurations of the guests were determined to be the same. In contrast, GNPS⊃ 1 gave one more C–H⋯π interaction which led to the confinement of 1 in the cavity of GNPS instead of being captured in the channel of GBPS, 18 indicating that GNPS can provide much stronger aromatic interactions. Next, we studied the host–guest properties of 2 , 3 and 4 with GNPS, which had never been crystallized with GBPS as the coformer.…”

“…Furthermore, the final refinement resulted in a large R = 0.1422. 18 By using GNPS as the host, NMR spectra were measured to detect chemical shift changes of protons on both the host GNPS and guest 1; however, the peaks ascribed to naphthalenedisulfonic acid (Ha, Hb, Hc) and guanidinium (Hd) only showed marginal changes [down-field 0.03, 0.03, 0.01 and 0.04 ppm (Fig. 4a), respectively], and the protons H-9 and H-10 on guest 1 also showed very small changes (upfield 0.01 ppm), suggesting that the perturbation of chemical shifts was very small.…”

“…In our previous study, 18 we used guanidinium–biphenyldisulfonic acid (GBPS) for the molecular structure determination of a wide range of liquid chemicals, and we found that hybrid interactions especially aromatic interactions play important roles in the crystal structures. However, the two benzene rings in biphenyldisulfonic acid make a dihedral angle of 31.0°, which weakens the aromatic interactions between the host and guest.…”