Qingzhao Zhang

Mentor: Dr. Sharon Burgmayer

Chemistry Department

Study of two Polypyridyl Ruthenium Complexes on DNA Interaction & Photocleavage

(a)  (b)(c)

Figure 1 (a) Terminal ring cleaved [Ru (bpy)2(L-pteridine)]2+ complex (b) [Ru(bpy)2 (L-diamino)]2+ (c) [Ru(bpy)2(L-Me2allox)]2+

Ruthenium (II) polypyridyl complexes, known for their special photophysical properties, are very remarkable for their abilities of preferentially targeting tumor cells. [Ru(bpy)2(L-pteridine)]2+ complexes, as a subcategory of those complexes have previously been identified to undergo pBR322 plasmid photocleavage through a singlet oxygen mechanism only when the terminal ring of pteridine ligand was cleaved Figure 1(a). Two exceptions to this generality were [Ru (bpy)2 (L-diamino)]2+ Figure 1(b) and [Ru(bpy)2(L-Me2allox)]2+ Figure 1(c) both with  closed terminal rings on pteridine ligand. Recent studies have shown that both complexes underwent moderate to strong DNA photocleavage after long sitting in buffer solution. The experiments are underway to determine the cause of this behavior. The synthesis will be conducted under higher temperature, and with the addition of base or acid. Degradation test will also be performed and monitored by Mass Spectroscopy (MS) and Nuclear magnetic resonance (NMR).