Structure and hydrogen bonding in 2,4-dihydroxybenzoic acid at 90, 100, 110 and 150 K; a theoretical and single-crystal X-ray diffraction study

Abstract

A new polymorph of 2,4-dihydroxybenzoic acid is reported. The structure was characterized by multiple-temperature X-ray diffraction and solid-state DFT computations. The material shows a geometric pattern of hydrogen bonding consistent with cooperativity between the intermolecular carboxylic acid dimer and intramolecular hydrogen bonds. The presence of proton disorder within this hydrogen-bond system, which would support such a cooperative model, was not fully ruled out by the initial X-ray studies. However, solid-state calculations on the three possible end-point tautomers indicate that the dominant crystallographically observed configuration is substantially lower in energy than the other tautomers (by at least 9 kJ mol(-1)), indicating that no disorder should be expected. It is therefore concluded that no disorder is observed either in the intra- or intermolecular hydrogen bonds of the title compound and that the cooperativity between the hydrogen bonds is not present within the temperature range studied.

Double proton transfer in crystals of 1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐a] pyrimidine (hppH):13C and15N CPMAS NMR study of (hppH)2

“…Intermolecular solid‐state proton transfer (ISSPT) is a phenomenon observed for only a few families of molecules. Double proton transfer was observed by Ernst in 1990 in dimers of benzoic acids, and has been the subject of several studies since that time 1–6. Prior to these observations, a triple proton transfer was reported for 3,5‐dimethylpyrazole trimer7 that was subsequently extended to double and quadruple proton transfers in other pyrazole cyclamers,8–11 as well as to 1,2,4‐triazoles 12.…”

A combined experimental and theoretical analysis on molecular structure and vibrational spectra of 2,4-dihydroxybenzoic acid

“…In 2007, Parkin et al [9] made an effort on its crystal structure and hydrogen bonding by multiple temperature single-crystal http://dx.doi.org/10.1016/j.saa.2014.08.151 1386-1425/Ó 2014 Elsevier B.V. All rights reserved. X-ray diffraction study.…”

Co-crystal/salt crystal structure disorder of trichloroacetic acid–N-methylurea complex with double system of homo- and heteronuclear O–H···O/N–H···O hydrogen bonds: X-ray investigation, ab initio and DFT studies

“…Among the functional groups used most frequently in crystal engineering is a carboxyl group and its derivatives in relation to amine derivatives. On supramolecular chemistry basis proton donors (organic acid) and acceptors (organic bases) are promising agents to generate stable multi-component hydrogen bonded systems with possible proton transfer via salt bridge [30][31][32][33][34].…”