Siewert Bianka, Langerman Michiel, Pannwitz Andrea, Bonnet Sylvestre
Leiden Institute of Chemistry Leiden University Einsteinweg 55 233CC Leiden The Netherlands.
Eur J Inorg Chem. 2018 Oct 9;2018(37):4117-4124. doi: 10.1002/ejic.201800644. Epub 2018 Aug 20.
In this work the synthesis, photochemistry, and streptavidin interaction of new Ru(tpy)(bpy)(SRR') complexes where the R' group contains a free biotin ligand, are described. Two different ligands SRR' were investigated: An asymmetric ligand where the Ru-bound thioether is a -acetylmethionine moiety linked to the free biotin fragment via a triethylene glycol spacer and a symmetrical ligand containing two identical biotin moieties. The coordination of these two ligands to the precursor [Ru(tpy)(bpy)Cl]Cl was studied in water at 80 °C. In such conditions the coordination of the asymmetric ligand occurred under thermodynamic control. After the reaction, a mononuclear and a binuclear complex were isolated. In the mononuclear complex, the ratio of methionine- {} vs. biotin-bound {} regioisomer was 5.3 and the free biotin fragment of allowed to purify it from its isomer at small scales using avidin affinity chromatography. Coordination of the symmetrical ligand afforded Ru(tpy)(bpy)() {} in synthetically useful scales (100 mg), good yield (82 %), and without traces of the binuclear impurity. In this complex, one of the biotin remains free whereas the second one is coordinated to ruthenium. Photochemical release of ligand from occurred upon blue light irradiation (465 nm) with a photosubstitution quantum yield of 0.011 that was independent of the binding of streptavidin to the free biotin ligand.
在本工作中，描述了新型Ru(tpy)(bpy)(SRR')配合物的合成、光化学以及与链霉亲和素的相互作用，其中R'基团包含一个游离的生物素配体。研究了两种不同的配体SRR'：一种不对称配体，其中与钌结合的硫醚是通过三甘醇间隔基与游离生物素片段相连的α-乙酰甲硫氨酸部分；以及一种含有两个相同生物素部分的对称配体。在80℃的水中研究了这两种配体与前体[Ru(tpy)(bpy)Cl]Cl的配位情况。在这种条件下，不对称配体的配位是在热力学控制下发生的。反应后，分离出了单核和双核配合物。在单核配合物中，甲硫氨酸结合的{}与生物素结合的{}区域异构体的比例为5.3，并且的游离生物素片段使得可以使用抗生物素蛋白亲和色谱法在小规模下从其异构体中纯化它。对称配体的配位以合成有用的规模（100 mg）、良好的产率（82%）且无双核杂质痕迹的情况下得到了Ru(tpy)(bpy)() {}。在该配合物中，一个生物素保持游离状态，而另一个与钌配位。蓝光照射（465 nm）时，的配体发生光化学释放，光取代量子产率为0.011，且该产率与链霉亲和素与游离生物素配体的结合无关。
