
pmid: 17413237
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.
Coumarins, Hydrocarbons, Chlorinated, Heterocyclic Compounds, 2-Ring, Hydrocarbons, Brominated
Coumarins, Hydrocarbons, Chlorinated, Heterocyclic Compounds, 2-Ring, Hydrocarbons, Brominated
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 25 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Average | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
