Abstract
The higher reduction products of dications of methyl viologen (MV2+), diquat (DQ(2+)) and n-butyl viologen (BV2+) i.e. MV; DO; and BV; respectively were prepared and their spectra recorded. MO calculation have been carried out to interpret the optical spectra of MV; and DQ:. A good agreement was obtained between experimental and predicted singlet transitions for MV: while in case of DQ: the agreement for singlet ransition at longer wave length was at variance.
In case of MV:(I) the observed transition are 3.1307 and 3.3056 eV while calculated one are 3.1352 (B-2u) and 3.4006 (B-3u) eV respectively where as in case of DQ: (II) the observed transitions are 3.0228 and 3.1307 eV while the calculated one are 2.6032 (B-1) and 3.0873 (A(1)) eV respectively.