Hurley Dennis J, Tor Yitzhak
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358, USA.
J Am Chem Soc. 2002 Apr 10;124(14):3749-62. doi: 10.1021/ja0123103.
A general and versatile method for the site-specific incorporation of polypyridine Ru(II) and Os(II) complexes into DNA oligonucleotides using solid-phase phosphoramidite chemistry is reported. Novel nucleosides containing a (bpy)(2)M(3-ethynyl-1,10-phenanthroline) (M = Ru, Os) metal center covalently attached to the 5-position in 2'-deoxyuridine are synthesized, and their electrochemical as well as photophysical properties are studied. The Ru(II) nucleoside exhibits a rather long-lived excited state in phosphate buffer pH 7.0 (tau = 1.08 micros) associated with a relatively high emission quantum efficiency (phi = 0.051). The solvent dependence of the absorption and emission spectra is consistent with an emissive MLCT state where charge localization takes place on the extended heterocycle-linked phenanthroline. In contrast, the Os(II)-containing nucleoside is quite nonemissive in aqueous environment (tau = 0.027 micros, phi = 1 x 10(-4)). The metal-containing nucleosides are converted into their phosphoramidites and are utilized for the high-yield preparation of modified oligonucleotides. The novel oligonucleotides, characterized by absorption and emission spectroscopy, enzymatic digestion, and electrophoresis, form stable duplexes. Circular dichroism spectra confirm that the global conformation of the double helix is not altered by the presence of these polypyridyl complexes in the major groove. Metal-containing phosphoramidites with predetermined absolute configuration at the octahedral coordination center are synthesized and utilized for the synthesis of diasteromerically pure metal-containing DNA oligonucleotides. Emission spectroscopy suggests a higher protection of the Delta metal center from the bulk solvent and better accommodation within the major groove.
报道了一种使用固相亚磷酰胺化学方法将多吡啶钌（II）和锇（II）配合物位点特异性掺入DNA寡核苷酸的通用方法。合成了新型核苷，其含有共价连接到2'-脱氧尿苷5位的(bpy)(2)M(3-乙炔基-1,10-菲咯啉)（M = Ru，Os）金属中心，并研究了它们的电化学和光物理性质。钌（II）核苷在pH 7.0的磷酸盐缓冲液中表现出相当长寿命的激发态（τ = 1.08微秒），且具有相对较高的发射量子效率（φ = 0.051）。吸收光谱和发射光谱对溶剂的依赖性与发射性的MLCT态一致，电荷定域发生在扩展的杂环连接菲咯啉上。相比之下，含锇（II）的核苷在水性环境中相当不发光（τ = 0.027微秒，φ = 1×10(-4)）。含金属的核苷被转化为它们的亚磷酰胺，并用于高产率制备修饰的寡核苷酸。通过吸收和发射光谱、酶切和电泳表征的新型寡核苷酸形成稳定的双链体。圆二色光谱证实，大沟中这些多吡啶配合物的存在不会改变双螺旋的整体构象。合成了在八面体配位中心具有预定绝对构型的含金属亚磷酰胺，并用于合成非对映体纯的含金属DNA寡核苷酸。发射光谱表明，δ金属中心受到来自本体溶剂的更高保护，并且在大沟内具有更好的适应性。
