Kirsch-De Mesmaeker A, Orellana G, Barton J K, Turro N J
Department of Chemistry, Columbia University, New York, NY 10027.
Photochem Photobiol. 1990 Sep;52(3):461-72. doi: 10.1111/j.1751-1097.1990.tb01787.x.
The nature of the interaction in buffered aqueous solution of several homo and heteroleptic ruthenium(II) polypyridyl complexes containing 2,2'-bipyridine (bpy), 2,2'-bipyrazine (bpz), 1,10-phenanthroline (phen), 4,7-diphenyl-1,10-phenanthroline (dip), 3,4,7,8-tetramethyl-1,10-phenanthroline (tmp), 1,4,5,8-tetraazaphenanthrene (tap), and 1,4,5,8,9,12-hexaazatriphenylene (hat) with calf thymus DNA and poly(dA-dT).poly(dA-dT) (pdAT) has been investigated by steady-state spectroscopy and emission lifetime measurements. Those complexes containing two or more tap/hat ligands photo-oxidize the guanine base upon binding to DNA with efficiencies that parallel their excited state redox potentials, but display "normal" behavior (increase of both the emission intensity and lifetime) when bound to pdAT. However Ru(tap)(hat)2+2 and Ru(hat)2+3 even photooxidize the adenine base of pdAT, so that their excited states are also quenched in the presence of either polynucleotide. The electron transfer quenching mechanism has been confirmed previously by detection of the monoreduced complex in laser flash photolysis experiments in the presence of mononucleotides. Most of the complexes investigated appear to bind to DNA, at least in part via intercalation, with affinities being dependent on the nature of the largest ligand (hat shows the highest ability in heteroleptic complexes). From lifetime quenching experiments, in the presence of moderate amounts of NaCl, surface binding does not appear to be a general mode for the complexes investigated, and it has been demonstrated unequivocally only for Ru(phen)2+3. In addition, the intercalation of complexes into DNA increases as the ionic strength of the medium decreases, the DNA/Ru ratio increases, or when water is partially replaced by glycerol.
通过稳态光谱和发射寿命测量，研究了几种含有2,2'-联吡啶（bpy）、2,2'-联吡嗪（bpz）、1,10-菲咯啉（phen）、4,7-二苯基-1,10-菲咯啉（dip）、3,4,7,8-四甲基-1,10-菲咯啉（tmp）、1,4,5,8-四氮杂菲（tap）和1,4,5,8,9,12-六氮杂三亚苯（hat）的同配和异配钌（II）多吡啶配合物在缓冲水溶液中与小牛胸腺DNA和聚（dA-dT）·聚（dA-dT）（pdAT）的相互作用性质。那些含有两个或更多tap/hat配体的配合物在与DNA结合时会光氧化鸟嘌呤碱基，其效率与它们的激发态氧化还原电位平行，但与pdAT结合时表现出“正常”行为（发射强度和寿命均增加）。然而，Ru（tap）（hat）2 + 2和Ru（hat）2 + 3甚至会光氧化pdAT的腺嘌呤碱基，因此在存在任何一种多核苷酸时它们的激发态也会被猝灭。电子转移猝灭机制先前已通过在单核苷酸存在下的激光闪光光解实验中检测单还原配合物得到证实。所研究的大多数配合物似乎至少部分通过嵌入与DNA结合，亲和力取决于最大配体的性质（在异配配合物中hat表现出最高能力）。从寿命猝灭实验来看，在适量NaCl存在下，表面结合似乎不是所研究配合物的普遍模式，并且仅对Ru（phen）2 + 3已明确证实。此外，配合物嵌入DNA的程度会随着介质离子强度降低、DNA/Ru比率增加或水被甘油部分替代而增加。
