The hypochromic shift resulting after interaction of the sample with CTDNA is associated with the contraction of DNA and a change in its conformation whereas hyperchromic shift
is shown to cause damage to the double helix of DNA .
Lead showed red hyperchromic shift while the other metals showed hyper- or hypso-chromatic deviation in absorbance from the reference compound 4.
This type of behavior was also observed in the excitation and emission spectra of compound 6 with hyperchromic shift for Pb2+.
The remaining metal ions appeared small difference in their hypso- and hyperchromic shifts of UV/Vis results.
This is presumably due to the electron delocalization of the chromophoric group resulted from grafting benzophenone chromophoric group to the main polymer chains, and so the extended chromophoric conjugation contributed to bathochromic and hyperchromic shifts
in UV-VIS absorption .