SYNTHESIS AND STRUCTURE OF THE RUTHENIUM(II) COMPLEXES )ME(5))RU(NO)(BIPY)](2-C(5)ME(5))RU(NO)(DPPZ)](2+) - DNA CLEAVAGE BY AN ORGANOMETALLIC DPPZ COMPLEX (BIPY=2,2'-BIPYRIDINE, DPPZ=DIPYRIDO[3,2-A() AND [(ETA)2',3'-C]PHENAZINE)/

The salts [(eta-C(5)Me(5))Ru(NO)(bipy)][OTf](2) (1[OTf](2)) and [(eta- C(5)Me(5))Ru(No)(dppz)][OTf](2) (2[OTf](2)) are obtained from the trea tment of (eta-C(5)Me(5))Ru(NO)(OTf)(2) with 2,2'-bipyridine (bipy) or dipyrido[3,2-a:2',3'-c]phenazine (dppz) (OTf = OSO2CF3). X-ray data fo r 1[OTf](2): monoclinic space group P2(1)/c, a = 11.553 (4) Angstrom, b = 16.517 (5) Angstrom, c = 14.719 (4) Angstrom, beta = 94.01 (2)degr ees, V = 2802 (2) Angstrom(3), Z = 4, R1 = 0.0698. X-ray data for 2[OT f](2): monoclinic space group P2(1)/c, a = 8.911 (2) Angstrom, b = 30. 516 (5) Angstrom, c = 24.622 (4) Angstrom, beta = 99.02(1)degrees, V = 6613 (2) Angstrom(3), Z = 8, R1 = 0.0789. Both 1[OTf](2) and 2[OTf](2 ) are soluble in water where they exhibit irreversible electrochemical oxidation and reduction. A fluorescence-monitored titration of a DNA solution containing 2[OTf](2) with ethidium bromide provides evidence that 2(2+) intercalates into DNA with a binding constant greater than 10(6) M(-1). DNA cleavage occurs when the DNA solutions containing 2[O Tf]2 are photolyzed or treated with H2O2 or K2S2O8.