title: Crystal structure of the magnesium salt of the herbicide 2,4-D: penta-aqua-[(2,4-di-chloro-phenoxy)acetato-κO]magnesium (2,4-di-chloro-phen-oxy)acetate hemihydrate.
abstract: In the crystal structure of the title magnesium salt of the phen-oxy herbicide (2,4-di-chloro-phen-oxy)acetic acid (2,4-D), [Mg(C8H5Cl2O3)(H2O)5](C8H5Cl2O3)·0.5H2O, the discrete cationic MgO6 complex unit comprises a carboxyl-ate O-donor from a monodentate 2,4-D anionic ligand and five water mol-ecules, resulting in a slightly distorted octa-hedral coordination sphere. The free 2,4-D anions are linked to the complex units through duplex water-carboxyl-ate O-H⋯O hydrogen bonds through the coordinating water mol-ecules. In the crystal, inter-unit O-H⋯O hydrogen-bonding inter-actions involving coordinating water mol-ecules as well as the solvent water mol-ecule (occupancy 0.5) with carboxyl-ate O-atom acceptors, give a layered structure lying parallel to (001), in which π-π ligand-cation inter-actions [minimum ring centroid separation = 3.6405 (17) Å] and a short O-H⋯Cl inter-action are also found.
authors.affiliation: Science and Engineering Faculty, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia.
authors.forename: Graham
authors.initials: G
authors.lastname: Smith
keywords: (2,4-di­chloro­phen­oxy)acetic acid; crystal structure; hydrogen bonding; magnesium complex; phen­oxy herbicide