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

摘要

The redox behaviour of 3 × 10-3M each of CuCl2.2H2O and CuBr2.H20 have been investigated at Platinum (Pt) electrode and 1 × 10-3M 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 CuCl2System, Epc1and E0are more positive, ?Ep is smaller and Ipa1/Ipc1is at GCE than at Pt electrode, exception being ethanol where opposite trend is observed. In ethanol, two reduction steps c1/a1due to Cu2+/ Cu+couple while a2/c2due to Br-/Br2couple are observed in CuBr2system. The electron paramagnetic resonance (EPR) features of copper (II) chloro species in DMF and DMSO show splitting of the gIIin frozen solution. For frozen CuBr2system, the spectral features in DMF, DMSO and ethanol are characterized by four small peaks in the gIIand one g^signal as found for CuCl2in ethanol. However, splitting of the gIIpeak occurs in AN which was not observed in similar solvent for CuCl2.