Synthesis and characterization of diaquo bis(n – 2 – aminopropyl acetylacetonato) copper (ii) complex

Abstract

N – 2 – aminopropyl acetylacetone Schiff base was prepared from the reaction of 2 – aminopropanoic acid and acetylacetone. The reaction of the Schiff base with copper (II) chloride formed diaquo bis( N – 2 – aminopropyl acetylacetonato) copper (II) complex. The Schiff base is crystalline orange yellow, has a yield of 53% and melting point of 160oC. The prepared diaquo bis( N – 2 – aminopropyl acetylacetonato) copper (II) complex is crystalline blue, has a yield of 70% and decomposition temperature of 245oC. The N – 2 – aminopropyl acetylacetone Schiff base is soluble in most solvents including water, but insoluble in ether. Its copper (II) complex is soluble in water, DMSO and DMF, but insoluble in most common organic solvents. The molar conductance of copper (II) Schiff base complex determined is 26 ohm-1 cm2 mol-1. The infra-red spectral data of the Schiff base and its copper (II) complex showed bands in the range 1607 – 1641 and 1589 - 1624cm-1, respectively, assignable to v(C=N) stretching vibrations. The broad bands in the range 3294 - 3428 and 3342 - 3402cm-1 are attributable to v(O-H) stretching frequencies in the Schiff base and its complex compound, respectively. The weak bands at 534 and 376 cm-1 are attributable to v(Cu-O) and v(Cu-N) stretching vibrations, respectively in the copper (II) Schiff base complex. The dissociation constant (pKa) of N – 2 – aminopropyl acetylacetone schiff base determined is 4.17. The stability constant and Gibb’s free energy of copper (II) Schiff base complex determined are 4.5x109 and -5.50x104 Jmol-1, respectively. The ratio of copper (II) ion to N – 2 – aminopropyl acetylacetone schiff base determined is 1:1.