Copper(II) Complexes with Phthalic Acid

Abstract

Abstract Three copper(II) complexes with phthalic acid, [Cuph(H2O)] (I) (ph=C6H4(COO)2), [Cu(Hph)2(H2O)2] (II), and [Cuph]2 (III), were prepared. Compound I was prepared from an aqueous solution of copper sulfate and phthalic acid within the temperature range of 60–79°C. It was a light blue crystal forming a hexagonal unit, the parameters being a=13.07 Å and c=13.98 Å and with the chemical unit Z equalling 8. II was prepared at a temperature below 60°C. It was a blue crystal having a hexagonal unit of a=11.42 Å, c=13.68 Å, and Z=4. The magnetic moments of I and II were 1.87 B. M. and 1.96 B. M. (both 21.5°C) respectively, showing I and II to have a monomer structure with respect to the two copper atoms. III could be prepared at temperatures above 79°C. It was a bluish-green crystal containing a hexagonal unit of a=12.77 Å, c=13.02 Å, and Z=4. The magnetic moment of III was found to be 1.54 B. M. (18.4°C), suggesting that complex III consisted of a dimer structure with respect to the copper atoms. The appearance of a shoulder near 370 mμ. in the reflection spectra of the copper complex III in the powdered crystalline state confirmed the suggestion of a dimer structure.