Crystal and molecular structure of bis(imazapyr)diaqua copper(II)

The imidazolinone herbicide imazapyr, 2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid (H(2)imz) interacts with Cu(II) leading to [Cu(Himz)(2)(H2O)(2)] which crystallizes in the space group Pbca, with a = 12.5370(3) Angstrom, b = 19.8500(5) Angstrom, c = 22.7720(9) Angstrom, and Z = 8. The Cu(II) atom is octahedrally surrounded by four nitrogen atoms of two Himz(-) anions and two water molecules. Each Himz(-) acts as a chelating ligand by means of N pyridine and N lactam atoms leading to five-membered chelate rings. The Cu-N distances vary from 1.948(4) to 2.299(5) Angstrom while the Cu-O are 2.114(5) and 2.256(6) Angstrom. The imidazol N-H are involved in short intramolecular hydrogen bonds with the carboxylate groups. The structure is stabilized by an intermolecular hydrogen-bonded network involving the water molecules and the carboxylate groups.