title: Carbonyl-carbonyl, carbonyl-pi and carbonyl-halogen dipolar interactions as the directing motifs of the supramolecular structure of ethyl 6-chloro-2-oxo-2H-chromene-3-carboxylate and ethyl 6-bromo-2-oxo-2H-chromene-3-carboxylate.
abstract: The title compounds, C(12)H(9)ClO(4), (I), and C(12)H(9)BrO(4), (II), are isomorphous and crystallize in the monoclinic space group P2(1)/c. Both compounds present an anti conformation between the 3-carboxy and the lactone carbonyl groups. Both carbonyl groups are out of the plane defined by the remaining chromene atoms, by 8.37 (6) and 17.57 (6) degrees for (I), and by 9.07 (8) and 18.96 (18) degrees for (II), owing to their involvement in intermolecular interactions. In both compounds, layers of centrosymmetric hydrogen-bonded dimers are developed in the [-5 -2 22] plane through C-H...O interactions, involving both carbonyl groups as acceptors. Two families of dimers stack through C=O...C=O, C=O...pi and C-X...C=O (X = Cl and Br) dipolar interactions, as well as a C-H...pi interaction, developing the three-dimensional structure along the c axis.
authors.affiliation: Facultad de Ciencias Químicas, Universidad de Colima, Carretera Coquimatlán, Colima 28400, Mexico.
authors.forename: Rocio J
authors.initials: RJ
authors.lastname: Santos-Contreras
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Martínez-Martínez
authors.forename: Efrén V
authors.initials: EV
authors.lastname: García-Báez
authors.forename: Itzia I
authors.initials: II
authors.lastname: Padilla-Martínez
authors.forename: Ana L
authors.initials: AL
authors.lastname: Peraza
authors.forename: Herbert
authors.initials: H
authors.lastname: Höpfl
mesh_terms: D003374:Coumarins / Q000737:chemistry*; D006574:Heterocyclic Compounds, 2-Ring / Q000737:chemistry*; D006842:Hydrocarbons, Brominated / Q000737:chemistry*; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry*
chemical_list: D003374:Coumarins; D006574:Heterocyclic Compounds, 2-Ring; D006842:Hydrocarbons, Brominated; D006843:Hydrocarbons, Chlorinated; C520994:ethyl 6-bromo-2-oxo-2H-chromene-3-carboxylate; C520993:ethyl 6-chloro-2-oxo-2H-chromene-3-carboxylate