Vidal Alessio, Calligaro Rudy, Gasser Gilles, Alberto Roger, Balducci Gabriele, Alessio Enzo
Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy.
Chimie ParisTech, PSL University, CNRS, Institute of Chemistry for Life and Health Sciences, Laboratory for Inorganic Chemistry, 75005 Paris, France.
Inorg Chem. 2021 May 17;60(10):7180-7195. doi: 10.1021/acs.inorgchem.1c00240. Epub 2021 Apr 28.
We describe a synthetic strategy for the preparation of bis-heteroleptic polypyridyl Ru(II) complexes of the type [Ru(L1)(L2)] (L1 and L2 = diimine ligands) from well-defined Ru(II) precursors. For this purpose, a series of six neutral, anionic, and cationic -locked Ru(II)-DMSO complexes (-) of the general formula [Y] -[RuX(DMSO-S)(O-O)] (where O-O is a symmetrical chelating anion: oxalate (ox), malonate (mal), acetylacetonate (acac); X = DMSO-O or Cl; = -1/0/+1 depending on the nature and charge of X and O-O; when present, Y = K or PF) were efficiently prepared from the well-known -[RuCl(DMSO)] (). When treated with diimine chelating ligands (L1 = bpy, phen, dpphen), the compounds - afforded the target [Ru(L1)(O-O)] complex together with the undesired (and unexpected) [Ru(L1)] species. Nevertheless, we found that the formation of [Ru(L1)]can be minimized by carefully adjusting the reaction conditions: in particular, high selectivity toward [Ru(L1)(O-O)] and almost complete conversion of the precursor was obtained within minutes, also on a 100-200 mg scale, when the reactions were performed in absolute ethanol at 150 °C in a microwave reactor. Depending on the nature of L1 and concentration, with the oxalate and malonate precursors, the neutral product [Ru(L1)(O-O)] can precipitate spontaneously from the final mixture, in pure form and acceptable-to-good yields. When spontaneous precipitation of the disubstituted product does not occur, purification from [Ru(L1)] can be rather easily accomplished by column chromatography or solvent extraction. By comparison, under the same conditions, compound is much less selective, thus demonstrating that locking the geometry of the precursor through the introduction of O-O in the coordination sphere of Ru is a valid strategic approach. By virtue of its proton-sensitive nature, facile and quantitative replacement of O-O in [Ru(L1)(O-O)] by L2, selectively affording [Ru(L1)(L2)], was accomplished in refluxing ethanol in the presence of a slight excess of trifluoroacetic acid or HPF.
我们描述了一种由明确的Ru(II)前体合成[Ru(L1)(L2)]型（L1和L2 = 二亚胺配体）双异质多吡啶Ru(II)配合物的策略。为此，从著名的[RuCl(DMSO)]合成了一系列通式为[Y] -[RuX(DMSO-S)(O-O)]的六种中性、阴离子和阳离子锁定的Ru(II)-DMSO配合物（-）（其中O-O是对称螯合阴离子：草酸盐（ox）、丙二酸盐（mal）、乙酰丙酮盐（acac）；X = DMSO-O或Cl；根据X和O-O的性质和电荷， = -1/0/+1；当存在时，Y = K或PF）。当用二亚胺螯合配体（L1 = bpy、phen、dpphen）处理时，化合物 - 得到目标[Ru(L1)(O-O)]配合物以及不需要的（且意外的）[Ru(L1)]物种。然而，我们发现通过仔细调整反应条件可以将[Ru(L1)]的形成降至最低：特别是，当反应在微波反应器中于150°C的无水乙醇中进行时，即使在100 - 200 mg规模下，几分钟内也能获得对[Ru(L1)(O-O)]的高选择性和前体的几乎完全转化。根据L1的性质和浓度，使用草酸盐和丙二酸盐前体时，中性产物[Ru(L1)(O-O)]可从最终混合物中自发沉淀，呈纯形式且产率良好至可接受。当二取代产物不发生自发沉淀时，通过柱色谱法或溶剂萃取可以相当容易地从[Ru(L1)]中进行纯化。相比之下，在相同条件下，化合物 的选择性要低得多，这表明通过在Ru的配位球中引入O-O来锁定前体的几何结构是一种有效的策略。由于其对质子敏感的性质，在略过量的三氟乙酸或HPF存在下，于回流乙醇中实现了[Ru(L1)(O-O)]中的O-O被L2轻松且定量地取代，选择性地得到[Ru(L1)(L2)]。
