Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD, UK.
Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, UK.
Chemistry. 2018 Oct 22;24(59):15859-15867. doi: 10.1002/chem.201803021. Epub 2018 Oct 1.
The new complexes [Ru(TAP) (11-CN-dppz)] , [Ru(TAP) (11-Br-dppz)] and [Ru(TAP) (11,12-diCN-dppz)] are reported. The addition of nitrile substituents to the dppz ligand of the DNA photo-oxidising complex [Ru(TAP) (dppz)] promote π-stacking interactions and ordered binding to DNA, as shown by X-ray crystallography. The structure of Λ-[Ru(TAP) (11-CN-dppz)] with the DNA duplex d(TCGGCGCCGA) shows, for the first time with this class of complex, a closed intercalation cavity with an AT base pair at the terminus. The structure obtained is compared to that formed with the 11-Br and 11,12-dinitrile derivatives, highlighting the stabilization of syn guanine by this enantiomer when the terminal base pair is GC. In contrast the AT base pair has the normal Watson-Crick orientation, highlighting the difference in charge distribution between the two purine bases and the complementarity of the dppz-purine interaction. The asymmetry of the cavity highlights the importance of the purine-dppz-purine stacking interaction.
报道了三种新的配合物[Ru(TAP)(11-CN-dppz)]、[Ru(TAP)(11-Br-dppz)]和[Ru(TAP)(11,12-diCN-dppz)]。与 DNA 光氧化复合物[Ru(TAP)(dppz)]中的 dppz 配体相比，氰基取代基的加入促进了π-堆积相互作用和与 DNA 的有序结合，这一点通过 X 射线晶体学得到了证明。[Ru(TAP)(11-CN-dppz)]与 DNA 双链 d(TCGGCGCCGA)的 Λ-结构首次显示了具有这种类别的复合物的封闭嵌入腔，并且在末端处具有一个 AT 碱基对。与 11-Br 和 11,12-二氰基衍生物形成的结构进行了比较，突出了当末端碱基对为 GC 时，这种对映异构体对顺式鸟嘌呤的稳定作用。相反，AT 碱基对具有正常的 Watson-Crick 取向，突出了两个嘌呤碱基之间的电荷分布差异以及 dppz-嘌呤相互作用的互补性。腔的不对称性突出了嘌呤-dppz-嘌呤堆积相互作用的重要性。
