Cu(II) AND Ni(II) COMPLEXES OF N, N′-bis(2-AMINOETHYL)-OXAMIDE AND N, N′-bis(3-AMINOPROPYL) OXAMIDE: A POTENTIOMETRIC AND SPECTROPHOTOMETRIC STUDY

Abstract

Extensive potentiometric and spectrophotometric (visible region) data resulted in the unravelling of the complete details of complex formation of N,N′-bis(2-aminoethyl) oxamide (L¹) and N,N′-bis(3-aminopropyl) oxamide (L²). This study reveals both similarities and differences in complex formation for these ligands. Earlier reports gave evidence for the formation of a Cu₃L₂H_-4 complex of L². We show that L¹ forms a Cu₂L₂H₂ complex. This difference in behaviour is due to a decrease in stability of the CuLH_-2 complex of L² compared to that of L¹. The complexation of Ni²⁺ by L¹ is also discussed.

Key Words:

• aminoalkyloxamides
• stability constants
• copper
• nickel
• potentiometry
• spectrophotometry