Chemical Speciation using Advanced Spectroscopic Methods

金属离子在工业上有着广泛的应用，在农业、催化、电池等方面都有应用。它们还具有多种生物医学应用，具有抗癌、放射性药物或抗菌活性。自20世纪70年代发现顺式铂（cis-[Pt(NH3)2Cl2]）作为第一种金属基抗癌化疗药物以来，许多研究活动都集中在开发具有抗癌特性的新型金属配合物上。其目标是鉴别出与顺铂相比对癌细胞具有更高选择性和更小毒副作用的化学试剂。***铑（2+）、钌（2+/3+）和铼（3+）离子的双金属配合物，以（O，O）或（O，N）供体架桥接在两个金属离子之间，呈（半）桨轮结构，是很有前途的金属基抗肿瘤活性化合物，以DNA为主要靶点。然而，这些药物并没有在临床上使用，主要是因为它们与其他生物分子的相互作用尚未完全了解。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光的x射线区域，它比太阳亮100多万倍，由世界各地的同步加速器设施生产，包括加拿大光源（CLS）。将使用最先进的显微镜技术和同步加速器光源来监测这些抗肿瘤活性复合物的细胞摄取，并绘制每个细胞中元素（如铑、铼、钌、硫和磷）的细胞内分布图。这些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。***我们也对新一代锂离子电池感兴趣，其中离子液体（ILs）用作不易燃电解质，锂（Li）金属用作阳极。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相（SEI）。根据所使用的IL类型，SEI可以是“有益的”，允许电池延长循环时间，或者是“有害的”，迫在眉睫的电池性能。我们将使用最先进的基于同步加速器的技术来识别在Li电极表面的SEI中形成的化学物质。在这个研究项目中，一些研究生和本科生将获得使用广泛的光谱技术的经验，如应用于生物医学和清洁能源应用。这项研究的另一个重要目的是促进加拿大的同步加速器科学，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.*****