2,2′-{[2-(2-Hydroxyphenyl)-4-methylimidazolidine-1,3-diyl]bis(methylene)}diphenol

The asymmetric unit in the title compound, C24H26N2O3, comprises two independent molecules (A and B). In molecule A, the central 2-hydroxyphenyl ring is inclined to the mean plane of the major component of the imidazolidine ring by 84.52 (14)°, and by 68.08 (9) and 47.48 (9)° to the outer phenol rings. The later are inclined to one another by 66.76 (9)° and by 78.12 (14) and 80.20 (14)° to the imidazoline ring mean plane. In molecule B, the central 2-hydroxyphenyl ring is inclined to the mean plane of the imidazolidine ring by 73.64 (10)°, and by 75.60 (8) and 38.32 (9)° to the outer phenol rings. The later are inclined to one another by 69.47 (9)° and by 82.60 (10) and 64.26 (10)° to the imidazolidine ring mean plane. In each of the independent molecules, two intramolecular O—H⋯N hydrogen bond form S(6) ring motifs. In disordered molecule A, the O—H groups of the 2-hydroxybenzyl groups are also involved in intramolecular O—H⋯O hydrogen bonds, with the O atom of the hydroxyphenyl group acting as the acceptor. In the crystal, A molecules are linked by pairs of O—H⋯O hydrogen bonds forming inversion dimers. These dimers are linked to the B molecules via O—H⋯O hydrogen bonds forming double-layered slabs lying parallel to the bc plane.

The C atoms of the both disorder components (minor and major) were refined harmonically with the ADP of C40′ equal to that of C40 and that of C26′ equal to ADP C26, due to the close proximity of these atoms. ADP values of the terminal C44 and C44′ methyl groups were refined independently. The distances C40-C26 and C40-C44 were kept equal to those of C40′-C26′ and C40′-C44′. The occupancies of the minor and major components refined so as to sum to unity.
The second molecule (B) exhibits a similar kind of disorder, but the relative occupancies of the methyl carbon refined to approximately 0.92 while the other methyl carbon occupancy was 0.08. Due to the very low occupancy of the minor component, we did not introduce disorder of the second molecule into the final structure model.
The hydroxyl H atoms were found in difference Fourier maps and their coordinates were refined with a distance

Figure 2
A perspective view of the molecule B of the title compound. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii.

Special details
Experimental. CrysAlisPro, Agilent, 2010 Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. Refinement. The refinement was carried out against all reflections. The conventional R-factor is always based on F. The goodness of fit as well as the weighted R-factor are based on F and F 2 for refinement carried out on F and F 2 , respectively. The threshold expression is used only for calculating R-factors etc. and it is not relevant to the choice of reflections for refinement. The program used for refinement, Jana2006, uses the weighting scheme based on the experimental expectations, see _refine_ls_weighting_details, that does not force S to be one. Therefore the values of S are usually larger than the ones from the SHELX program.