2-Oxo-2 H-chromen-7-yl 4- tert-butyl-benzoate

Acta Crystallogr E Crystallogr Commun. 2018 Mar 16;74(Pt 4):530-534. doi: 10.1107/S2056989018004188. eCollection 2018 Apr 1.


In the title compound, C20H18O4, the benzoate ring is oriented at an acute angle of 33.10 (12)° with respect to the planar (r.m.s deviation = 0.016 Å) coumarin ring system. An intra-molecular C-H⋯O hydrogen bond closes an S(6) ring motif. In the crystal, C-H⋯O contacts generate infinite C(6) chains along the b-axis direction. Also present are π-π stacking inter-actions between neighbouring pyrone and benzene rings [centroid-centroid distance = 3.7034 (18) Å] and C=O⋯π inter-actions [O⋯centroid = 3.760 (3) Å]. The data obtained from quantum chemical calculations performed on the title compound are in good agreement with the observed structure, although the calculated C-O-C-C torsion angle between the coumarin ring system and the benzoate ring (129.1°) is somewhat lower than the observed value [141.3 (3)°]. Hirshfeld surface analysis has been used to confirm and qu-antify the supra-molecular inter-actions.

Keywords: C—H⋯O hydrogen bond; Hirshfeld surface analysis; coumarin; crystal structure; quantum chemical calculations.