The chelate effect of a tridentate receptor is exploited to determine halogen bonding association constants that vary by several orders of magnitude, including interactions of weak donors for which thermodynamic data were not previously available. Free energy relationships with computed and experimental properties hold over this wide range of donors. The strengths of iodine- and bromine-based h...

In the title compound, C(11)H(8)Cl(2)N(2)O, the benzene and pyridazine rings are tilted by 8.6 (1)° relative to each other. In the crystal, pairs of inter-molecular N-H⋯O hydrogen bonds form centrosymmetric dimers. π-π contacts with centroid-centroid distances of 3.698 (2) and 3.751 (1) Å and halogen-halogen inter-actions [3.379 (1) Å] also stabilize the structure.

The title compound, C(13)H(12)Cl(2)O(5), is an isocoumarin compound which has been isolated from the ethyl acetate extract of the fermentation broth of actinomycete Streptomyces sp. (V(4)) from the South China Sea. There are intra- and inter-molecular hydrogen bonds and halogen bonds [Cl⋯Cl = 3.434 (2) Å; C-Cl⋯Cl = 121.6°]. The intermolecular O-H⋯O hydrogen bonds link mol-ecules into chains alo...

The mol-ecular structure of the title compound, C7H10Br2O4, confirms the meso (2R,6S) configuration. In the crystal, mol-ecules are linked by pairs of O-H⋯O=C hydrogen bonds between their terminal carboxyl groups in an R 2 (2)(8) motif, forming extended chains that propagate parallel to the c axis. Adjacent chains are linked by C=O⋯Br halogen bonds.

In recent years, several specific imidazolium-based ionic liquids with halogen substituents on the imidazole ring as well as on the alkyl chains have been reported. In this work, noncovalent interactions in four halogenated ionic liquids, i.e. 2-bromo-/iodo- and 4,5-dibromo-/diiodo-1,3-dimethylimidazolium trifluoromethanesulfonates, were systematically investigated using density functional theo...

Control of intermolecular interactions is integral to harnessing self-assembly in nature. Here we demonstrate that control of the competition between hydrogen bonds and halogen bonds, the two most highly studied directional intermolecular interactions, can be exerted by choice of solvent (polarity) to direct the self-assembly of co-crystals. Competitive co-crystal formation has been investigate...