Metal complexes of dicamba. II. The crystal structure of catena-m-[Diaquabis-(3,6-dichloro-2-methoxybenzoato(O,O')]-calcium(II)

Abstract

The crystal structure of a calcium complex of the herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) has been determined by single-crystal X-ray diffraction and refined by least squares to a final residual of 0.045. [Ca(dicamba)₂(H₂O)₂]_n is orthorhombic, space group Pbcn, Z 4, with a cell a 15.844(3), b 16.833(2), c 7.751(1) Å. The MO₈ coordination polyhedron about the calcium ion is a distorted Archimedes antiprism which has twofold rotational symmetry. There are two waters [Ca-O, 2.414(3) Å] and six carboxylate oxygens from two bidentate chelate groups [Ca-O, 2.516, 2.517(3) Å] and two bridging carboxyls [2.372(3) Å]. This results in an infinite linear polymer structure.