Influence of the Steric Bulk and Solvent on the Photoreactivity of Ruthenium Polypyridyl Complexes Coordinated to L-Proline
Influence of the Steric Bulk and Solvent on the Photoreactivity of Ruthenium Polypyridyl Complexes Coordinated to L-Proline
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DOI：
10.1021/acs.inorgchem.6b02794
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发表时间：
2017-05-01
影响因子：
4.6
通讯作者：
Bonnet, Sylvestre
中科院分区：
文献类型：
--
作者：
Cuello-Garibo, Jordi-Amat;Perez-Gallent, Elena;Bonnet, Sylvestre
唯一的多吡啶基络合物是光活化化疗（PACT）的良好候选者，只要它们在黑暗但有效地摄取其配体之一的稳定性。 Here the use of the natural amino acid l-proline as a protecting ligand for ruthenium-based PACT compounds is investigated in the series of complexes Lambda-[Ru(bpy)(2)(L-prol)]PF6 ([1a]PF6; bpy = 2,2'-bipyridine and L-prol = L-proline), lambda- [ru（bpy）（dmbpy）（l-prol）] pf6（[[2a] pf6和[2b] pf6; dmbpy = 6,6'-二甲基-2,2'-二吡啶）和lambda-- [rambda- [rambpy- [ru（dmbpy）（dmbpy）（dmbpy）（l-prol）（l-prol）（l-prol）（l-prol）（l-prol）（l-prol）Pf6（l-prol）pf6（pf6 pf6）（[3a]）。含有非对称脯氨酸配体的三型蛋白质复合物的合成仅产生了四个可能的区域异构体中的两个，称为[2a] pf6和[2b] pf6。两种异构体都是分离出来的，并通过光谱和密度函数理论计算的结合进行了特征。使用UVVIS光谱，圆形的二色谱学光谱，质谱和H-1 NMR Spemposey，使用UVVIS光谱，在水（H2O）和乙腈（MECN）中研究了所有四个复合物[1A] PF6，[2A] PF6，[2B] PF6和[3A] PF6的光反应性。在H2O中，在存在氧气的情况下可见光照射后，没有发生光合剥离，但是复杂的[1A] PF6的胺被光氧化为亚胺。与期望相反，通过在磷酸盐缓冲盐水（PBS）中添加两个（[2B] PF6）或四个（[3A] PF6）甲基取代基来增强空间菌株，并未引导。然而，它阻止了甲基取代基的电子粉饰作用的结果。此外，尽管[2b] PF6在PBS中是光稳定的，但[2a] PF6在光照射后定量异构为[2b] Pf6。在纯MECN中，[2A] PF6和[3A] PF6在L-丙酸酯和DMBPY配体中均表现出非选择性的摄影剂，而未造成的复合物[1A] PF6是光稳定的。最后，在H2omecn混合物中，[3A] PF6显示了L-丙啉的选择性摄影剂，从而证明了溶剂在该系列复合物的光反应性中所起的积极作用。讨论了溶剂极性和协调性能在多吡啶基络合物的光化学特性上的作用。
Ruthenium polypyridyl complexes are good candidates for photoactivated chemotherapy (PACT) provided that they are stable in the dark but efficiently photosubstitute one of their ligands. Here the use of the natural amino acid l-proline as a protecting ligand for ruthenium-based PACT compounds is investigated in the series of complexes Lambda-[Ru(bpy)(2)(L-prol)]PF6 ([1a]PF6; bpy = 2,2'-bipyridine and L-prol = L-proline), Lambda-[Ru(bpy)(dmbpy)(l-prol)]PF6 ([2a]PF6 and [2b]PF6; dmbpy = 6,6'-dimethyl-2,2'-bipyridine), and Lambda-[Ru(dmbpy)(2)(L-prol)]PF6 ([3a]PF6). The synthesis of the tris-heteroleptic complex bearing the dissymmetric proline ligand yielded only two of the four possible regioisomers, called [2a]PF6 and [2b]PF6. Both isomers were isolated and characterized by a combination of spectroscopy and density functional theory calculations. The photoreactivity of all four complexes [1a]PF6, [2a]PF6, [2b]PF6, and [3a]PF6 was studied in water (H2O) and acetonitrile (MeCN) using UVvis spectroscopy, circular dichroism spectroscopy, mass spectrometry, and H-1 NMR spectroscopy. In H2O, upon visible-light irradiation in the presence of oxygen, no photosubstitution took place, but the amine of complex [1a]PF6 was photooxidized to an imine. Contrary to expectations, enhancing the steric strain by the addition of two ([2b]PF6) or four ([3a]PF6) methyl substituents did not lead, in phosphate-buffered saline (PBS), to ligand photosubstitution. However, it prevented photoxidation, probably as a consequence of the electron-donating effect of the methyl substituents. In addition, whereas [2b]PF6 was photostable in PBS, [2a]PF6 quantitatively isomerized to [2b]PF6 upon light irradiation. In pure MeCN, [2a]PF6 and [3a]PF6 showed non-selective photosubstitution of both the L-proline and dmbpy ligands, whereas the non-strained complex [1a]PF6 was photostable. Finally, in H2OMeCN mixtures, [3a]PF6 showed selective photosubstitution of l-proline, thus demonstrating the active role played by the solvent on the photoreactivity of this series of complexes. The role of the solvent polarity and coordination properties on the photochemical properties of polypyridyl complexes is discussed.