An aqua complex of copper(II) o -azidobenzoate, [Cu(OH)ABA · 2 H 2 O ] 2 (ABA is Ó -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 Cu 2+ . When dissolved in dry organic solvents (DMF, DMSO, dioxane, and methanol), the complex undergoes dehydration to give a chelate complex (CC) containing the Cu 2+ -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 Cu 2+ ion with Ó -azidobenzoic acid in dry organic solvents affords a CC similar to the complex obtained on the dissolution of [Cu(OH)ABA · 2 H 2 O ] 2 in dry solvents.

An aqua complex of copper(II) ortho-azidobenzoate was synthesized. The formula of this complex, [Cu(OH)ABA · 2ç 2 é] 2 (ABA is ortho-azidobenzoate), was determined by IR, UV, and EPR spectroscopy and volumetric analysis (from the amount of nitrogen released upon dissolving the aqua complex in dry DMF). It was found that, in this aqua complex, the azido group is not coordinated to the copper(II) ion. On the dissolution of the aqua complex in dry organic solvents, such as DMF, DMSO, dioxane, and methanol, it underwent dehydration followed by the coordination of the azido group to copper(II) to convert into a chelate complex. The chelate complex in the solid state was stable at room temperature; however, it slowly degraded in solutions to liberate nitrogen. Dissolution in dry THF did not result in the dehydration of the complex. In the photolysis of the aqua complex in dry THF or a THF-water mixture, photochemical dehydration yielding the chelate complex occurred along with the degradation of the azido group and the formation of copper(II) anthranilate.