Chemical Speciation using Advanced Spectroscopic Methods

金属离子在工业、农业、催化、电池等领域有着广泛的应用。金属离子还具有抗癌、放射性药物或抗菌等多种生物医学应用。自从20世纪70年代发现顺铂(cis-[Pt(NH3)2Cl2])作为第一种金属抗癌化疗药物以来，许多研究活动都集中在开发具有抗癌性能的新的金属配合物上。其目标一直是确定与顺铂相比，对癌细胞具有更高选择性且毒副作用较小的化学试剂。 Rh(2)、Ru(2/3)和Re(3)的双金属配合物是以DNA为主要靶标，以(O，O)或(O，N)-供体为桥联的(半)桨轮结构连接在两个金属离子之间的双金属配合物。然而，这些化合物没有在临床上使用，主要是因为它们与其他生物分子的相互作用还没有完全了解。因此，我们将研究这些双金属配合物与选定的氨基酸的反应产物，包括组氨酸、蛋氨酸、半胱氨酸及其衍生物，以及三肽谷胱甘肽，作为这些双金属化合物与蛋白质和酶相互作用的模型。为此，我们将使用同步加速器的X射线区域，它的亮度比太阳高100多万倍，由世界各地的同步加速器设施产生，包括加拿大光源(CLS)。最先进的显微镜技术和同步辐射光源将被用来监测细胞对这些抗肿瘤活性络合物的摄取，并绘制每个细胞中元素如Rh、Re、Ru、S和P的细胞内分布图。这一知识将有助于了解这类抗肿瘤活性化合物进入细胞后的命运。 我们还对新一代锂离子电池感兴趣，其中离子液体(ILS)用作不可燃电解液，锂(Li)金属用作负极。由于Li的高活性表面，IL在其表面分解，形成固体电解质界面(SEI)。根据所使用的IL的类型，SEI可能是“有益的”，允许电池延长循环，或“有害”，影响电池的性能。我们将使用最先进的同步加速器技术来鉴定锂电极表面SEI中形成的化学物种。 在这项研究计划中，几名研究生和本科生将获得在生物医学和清洁能源应用中广泛使用光谱技术的经验。这项研究的另一个重要目的是在加拿大推广同步加速器科学，并培训萨斯卡通CLS设施的未来用户。

Metal ions are extensively used in industry with applications in agriculture, catalysis, batteries, etc. They also have diverse biomedical applications with anticancer, radiopharmaceutical or antibacterial activities. Since the discovery of cis-platin (cis-[Pt(NH3)2Cl2]) in the 1970s as the first metal-based anticancer chemotherapeutic agent, many research activities have focused on developing new metal complexes with anticancer properties. The goal has been to identify chemical reagents that have a higher selectivity toward cancerous cells and less toxic side effects compared with cis-platin. Bimetallic complexes of rhodium(2+), ruthenium(2+/3+) and rhenium(3+) ions, with (O,O) or (O,N)-donor species bridging between the two metal ions and a (semi) paddle wheel structure, are promising metal-based antitumor active compounds, with DNA as their primary target. However, these are not clinically in use mainly because their interactions with other biomolecules are not fully understood. We will therefore investigate the reaction products of these bimetallic complexes with selected amino acids, including histidine, methionine, cysteine and its derivatives, as well as the tri-peptide glutathione, as models for interactions of these bimetallic compounds with proteins and enzymes. For this purpose, we will use the X-ray region of synchrotron light, which is more than a million times brighter than the sun and is produced at synchrotron facilities around the world, including the Canadian Light Source (CLS). A state-of-the-art microscopy technique with a synchrotron light source will be used to monitor the cellular uptake of these antitumor active complexes and map the intracellular distribution of elements, such as rhodium, rhenium, ruthenium, sulfur and phosphorus, in each cell. This knowledge will help to understand the fate of this class of antitumor-active compounds as they enter the cell. We are also interested in a new generation of lithium ion batteries, in which ionic liquids (ILs) are used as non-flammable electrolytes and lithium (Li) metal as the anode. Due to the highly reactive surface of Li, the IL is decomposed at its surface and a solid electrolyte interphase (SEI) is formed. Depending on the type of IL used, the SEI can be “beneficial”, allowing extended cycling of the battery, or “detrimental”, impending the battery performance. We will use state-of-the-art synchrotron-based techniques to identify the chemical species formed in the SEI on the surface of Li electrodes. During this research program, several graduate and undergraduate students will gain experience in using a wide range of spectroscopic techniques, as applied to both biomedical and clean energy applications. Another important purpose of this research is to promote synchrotron science in Canada and to train future users of the CLS facility in Saskatoon.