Synthesis, complex formation kinetics and thermodynamic study of some acyclic polyamine and N2O2 ligands with copper(II)


ÖZAY H., Baran Y.

JOURNAL OF COORDINATION CHEMISTRY, vol.63, no.24, pp.4299-4308, 2010 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 63 Issue: 24
  • Publication Date: 2010
  • Doi Number: 10.1080/00958972.2010.535144
  • Journal Name: JOURNAL OF COORDINATION CHEMISTRY
  • Journal Indexes: Science Citation Index Expanded, Scopus
  • Page Numbers: pp.4299-4308
  • Keywords: Complexation, Polyamine, Kinetics, Stability constants, Stopped-flow, Spectrophotometric titration, COORDINATION PROPERTIES, EQUILIBRIA, ZN(II), CU(II), MACROCYCLES, NICKEL(II)

Abstract

The polydentate ligands, 3-(2-aminocyclohexylamino)-2-(2-aminocyclohexyl aminomethyl) propionic acid (L1), 4,7,10-triazatridecanedinitrile trihydrochloride (L2), and 2,20-(ethane-1,2-diyl) bis(methylazanediyl) diethanol (L3) were prepared and their structures investigated byFT-IR, NMR, and MS. The kinetics of complex formation between Cu(II) and L1, L2, andL3 were investigated in acidic aqueous solutions using the stopped-flow method. The stabilityconstants of the complexes were determined by spectrophotometric titration (T¼293 K,¼0.1 mol L1 NaClO4), using a diode array UV-Vis spectrophotometer equipped with peristaltic pump and pH meter. The stability constants for the complexes were CuL14CuL24CuL3. Activation enthalpies (DH#) of these complexes were 55 kJ mol1 for CuL1, 61 kJ mol1 for CuL2, and 36 kJ mol1 for CuL3, respectively.
The polydentate ligands, 3-(2-aminocyclohexylamino)-2-(2-aminocyclohexyl aminomethyl) propionic acid (L1), 4,7,10-triazatridecanedinitrile trihydrochloride (L2), and 2,2'-(ethane-1,2-diyl) bis(methylazanediyl) diethanol (L3) were prepared and their structures investigated by FT-IR, NMR, and MS. The kinetics of complex formation between Cu(II) and L1, L2, and L3 were investigated in acidic aqueous solutions using the stopped-flow method. The stability constants of the complexes were determined by spectrophotometric titration (T = 293 K, = 0.1 mol L-1 NaClO4), using a diode array UV-Vis spectrophotometer equipped with peristaltic pump and pH meter. The stability constants for the complexes were CuL1 CuL2 CuL3. Activation enthalpies (H#) of these complexes were 55 kJ mol-1 for CuL1, 61 kJ mol-1 for CuL2, and 36 kJ mol-1 for CuL3, respectively.