Crystal structure of a new polymorph of 3-acetyl-8-meth-oxy-2H-chromen-2-one
Gabino Gonzalez-Carrillo1, Roberto Muñiz-Valencia1, Efren V García-Báez2
1Facultad de Ciencias Químicas, Universidad de Colima, km 9 carretera, Colima-Coquimatlán, 28400, Coquimatlán, Colima, Mexico.
Abstract:
A new polymorphic form of the title compound, C12H10O4, is described in the ortho-rhom-bic space group Pbca and Z = 8, as compared to polymorph I, which crystallizes in the monoclinic space group C2/c and Z = 8 [Li et al. (2012). Chin. J. Struct. Chem. 31, 1003-1007.]. In polymorph II, the coumarin ring system is almost planar (r.m.s. deviation = 0.00129 Å). In the crystal, mol-ecules are connected by Csp 3-H⋯O and Car-H⋯O hydrogen bonds, forming mol-ecular sheets linked into zigzag shaped layers along the b-axis direction. The three-dimensional lattice is assembled through stacking of the zigzag layers by π-π inter-actions with a centroid-to-centroid distance of 3.600 (9) Å and anti-parallel C=O⋯C=O inter-actions with a distance of 3.1986 (17) Å, which give rise to a helical supra-molecular architecture.
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