African Journal of
Pure and Applied Chemistry

  • Abbreviation: Afr. J. Pure Appl. Chem.
  • Language: English
  • ISSN: 1996-0840
  • DOI: 10.5897/AJPAC
  • Start Year: 2007
  • Published Articles: 368

Full Length Research Paper

Redox and spectral behaviour of copper (II)-chloro and bromo complexes in some nonaqueous solvents

E. J. Ukpong1*, N. W. Akpanudo1 and J. Prasad2
1Department of Science Laboratory Technology, Akwa Ibom State College of Agriculture. P. M. B 1001, Abak, Nigeria. 2Chemistry Department, Allahabad University, Allahabad, India
Email: [email protected]

  •  Accepted: 22 January 2010
  •  Published: 30 April 2010

Abstract

The redox behaviour of 3 × 10-3 M each of CuCl2.2H2O and CuBr2.H20 have been investigated at Platinum (Pt) electrode and 1 × 10-3 M CuCl2.2H20 at glassy carbon (GCE) electrode in dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetonitrile (AN) and ethanol/0.1 M tetrabutylammonium perchlorate (TBAP) using cyclic voltammetry. For CuCl2 System, Epc1 and E0 are more positive, ∆Ep is smaller and Ipa1/Ipc1 is > at GCE than at Pt electrode, exception being ethanol where opposite trend is observed. In ethanol, two reduction steps c1/a1 due to Cu2+/ Cu+ couple while a2/c2 due to Br-/Br2 couple are observed in CuBr2system. The electron paramagnetic resonance (EPR) features of copper (II) chloro species in DMF and DMSO show splitting of the gII in frozen solution. For frozen CuBr2 system, the spectral features in DMF, DMSO and ethanol are characterized by four small peaks in the gII and one g^ signal as found for CuCl2in ethanol. However, splitting of the gII peak occurs in AN which was not observed in similar solvent for CuCl2.

 

Key words: Redox, spectral, voltammograph, EPR, nonaqueous, cupric halide.