Supramolecular Organic Salts Constructed from 6-Hydroxyquinoline and Nitrobenzoic Acids

Abstract

The crystal structures of the proton-transfer salts of 6-hydroxyquinoline with 3,5-dinitrobenzoic acid (1) and 4-nitrobenzoic acid (2) have been determined at room temperature. Their comparative structural features and hydrogen-bonding patterns are described here. Compound 1 crystallizes in the monoclinic P2 1 /c space group, while 2 in the triclinic P-1 space group. Unit cell dimensions and contents are: a = 7.6956 (15), b = 26.075(5), c = 7.7233 (15) Å , b = 95.96(3)°for 1; a = 7.7325(15), b = 8.5939 (17), c = 12.394(3) Å , b = 77.63(3)°for 2. Supramolecular architectures are formed by intermolecular hydrogen bonds in the proton-transfer process. The supramolecular structures are stabilized by N-HÁÁÁO, O-HÁÁÁO and C-HÁÁÁO hydrogen bonds between the two components. Extensive hydrogenbonding interactions give two-dimensional network structures. In addition, p-p stacking interactions exist in the salt 1 due to the aromatic rings.

Proton-transfer salts of diphenylphosphinic acid with substituted 2-aminopyridine: crystal structure, spectroscopic and DFT studies

“…The presence of hydrogen bonds between proton donors and acceptors plays an important role with respect to the formation and stability of 1:1 or 2:1 proton-transfer salts (Smith & Wermuth, 2010a,b, 2011, 2013c, 2014Smith et al, 2007Smith et al, , 2008Subha et al, 2022). Various organic bases can receive a proton and become protonated cations, examples being pyrazine (Lengyel et al, 2019), piperazine (Ding et al, 2014;Muslim et al, 2021;Subha et al, 2022), imidazole (Massey et al, 2016;Khan et al, 2021), indole (Ma et al, 2018), quinoline (Belombe et al, 2011;Li et al, 2012;Khan et al, 2022), 1,2,4-triazole and other azoles (Luo et al, 2011;Massey et al, 2012;Tucker et al, 2015;Singh et al, 2021), hydrazine (Smith et al, 2009), benzamidine (Portalone, 2010(Portalone, , 2014Irrera et al, 2012), sulfamethazine (Padrela et al, 2019), guanidine (Smith et al, 2007;Ghasemi et al, 2019), adenine (Sedghiniya et al, 2019) and amines (Rosokha et al, 2006;Zhang & Zhu, 2007;Ding et al, 2012Ding et al, , 2013Smith & Wermuth, 2013a, 2016Shmukler et al, 2019;El-Dissouky et al, 2020).…”