Redetermined structure of 4-(benzyloxy)benzoic acid

The molecules of the title compound form acid–acid homodimers in the crystal structure.

In the title compound, C 14 H 14 O 3 , the dihedral angle between the aromatic rings is 39.76 (9) � .In the crystal, the molecules associate to form centrosymmetric acid-acid dimers linked by pairwise O-H� � �O hydrogen bonds.The precision of the geometric parameters in the present single-crystal study is about an order of magnitude better than the previous powder diffraction study [Chattopadhyay et al. (2013).CrystEngComm, 15, 1077-1085].

Structure description
Non-steroidal anti-inflammatory drugs (NSAIDs) constitute approximately 5-10% of all prescribed medicines worldwide as antipyretic, anti-inflammatory and analgesic agents (Sohail et al., 2023).Moreover, they are found to have a protective role against various critical diseases, such as cancer and cardiovascular diseases (Prasher & Sharma, 2021).It is estimated that 30 million individuals use NSAIDs daily (Bhala et al., 2013).
As part of our studies in this area, the title compound (Fig. 1) was synthesized by a twostep reaction.The C1-C6 and C9-C14 aromatic rings subtend a dihedral angle of 39.76 (9) � and the linking C4-O3-C8-C9 bond has an anti conformation [torsion angle = À 171.59 (12) � ].The short C4-O3 bond length of 1.3601 (16) A ˚indicates some conjugation of the O atom lone pair with the adjacent aromatic ring.
In the extended structure, molecules pair up to form carboxylic acid-carboxylic acid hydrogen-bonded dimers (Table 1, Fig. 2).The crystal structure of the title compound was also solved from X-ray powder diffraction data (Chattopadhyay et al., 2013) with corresponding hydrogen-bond parameters of 1.94 A ˚and 176 � , respectively, which deviate from those obtained in this study from single-crystal X-ray diffraction.

Figure 2
Packing of the molecules in the title compound (for clarity, H atoms not involved in hydrogen bonding are omitted).

Figure 1
The molecular structure of the title compound with displacement ellipsoids drawn at the 50% probability level.

Special details
Geometry.All esds (except the esd in the dihedral angle between two l.s.planes) are estimated using the full covariance matrix.The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry.An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s.planes.

data reports data-2
IUCrData (2024).9, x240752 Refinement.The positions of the H atom attached to O1 was obtained from a difference Fourier map.Other H atoms were positioned geometrically with C-H = 0.93 Å and constrained to ride on their parent atoms with U iso (H) = 1.2U eq (C,O).

Table 2
Experimental details.