Study of complexation between Cu2+ ions and ortho-azidobenzoic acid

An aqua complex of copper(II) o-azidobenzoate, [Cu(OH)ABA2H₂O]₂ (ABA is o-azidobenzoic acid), was synthesized in an aqueous solution and identified by IR and electronic absorption spectroscopy. In the complex, the azido group is not coordinated by Cu²⁺. When dissolved in dry organic solvents (DMF, DMSO, dioxane, and methanol), the complex undergoes dehydration to give a chelate complex (CC) containing the Cu²⁺-coordinated azido group as a result of the electron density redistribution at its N atoms. The IR spectrum of the chelate complex contains no absorption band at 2135 cm^–1 corresponding to the stretching vibrations of the azido group. The resulting CC is unstable in solutions and spontaneously decomposes with a release of molecular nitrogen. The interaction of a Cu²⁺ ion with o-azidobenzoic acid in dry organic solvents affords a CC similar to the complex obtained on the dissolution of [Cu(OH)ABA2H₂O]₂ in dry solvents.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 195–198.Original Russian Text Copyright © 2005 by Budruev, Karyakina, Levina, Oleinik.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.