DIPYRIDOPHENAZINE COMPLEXES OF COBALT(III) AND NICKEL(II) - DNA-BINDING AND PHOTOCLEAVAGE STUDIES

Results of absorption titration, thermal denaturation, and differentia l pulse voltammetric experiments suggest that [Co(phen)(2)DPPZ](3+) an d [Ni(phen)(2)DPPZ](2+) (phen = 1, 10-phenanthroline and DPPZ = dipyri do[3,2-a:2',3'-c]phenazine) are both avid binders of calf thymus DNA. On the other hand, while the cobalt(III) complex has been found to eff ect the photocleavage of the supercoiled pBR 322 DNA, the nickel(II) c omplex is ineffective under similar experimental conditions.