Epitaxial Electrodeposition of Chiral Metal Oxide Films

许多生物分子都是手性的--它们可以以两种不同的对映体形式之一存在，只是它们的结构是彼此的镜像。由于一种对映体往往具有生理活性，而另一种对映体是无效的，甚至是有毒的，因此越来越多的药物化合物以对映体纯的形式使用液相均相催化剂和酶来生产。手性表面提供了开发多相对映体特异性催化剂的可能性，这些催化剂可以更容易地从产品中分离出来并重复使用。此外，这种表面可能作为手性分子的电化学传感器--甚至可能是可用于监测体内药物水平的植入式手性传感器。在这项工作中，利用酒石酸和氨基酸等手性分子将CuO、AgO、Bi2O3、PbO2、Tl_2O_3、Y_2O_3和In_2O_3等金属氧化物的手性表面电沉积到单晶金和铜等非手性表面上。没有镜面或滑动面对称性的表面将被电沉积。材料不需要在手性空间群中结晶。薄膜的绝对构型将通过X射线极图分析来确定，微观结构将通过电子显微镜和扫描探针显微镜来探测。在手性试剂存在的情况下，通过在碳酸氢钙溶液中电化学产生碱来沉积方解石，将探索电化学生物矿化的概念。将探索手性电沉积的机理，以确定手性分子是简单地模板表面还是印迹表面。这一机制将通过扫描隧道显微镜、振动光谱和电化学石英微天平等原位技术进行探索。最后，手性氧化物表面将被用来制造手性电化学传感器。这些传感器将用于手性识别简单的手性分子，如酒石酸和氨基酸，以及更复杂的药物。手性在自然界中无处不在。许多生物分子，如药物和化学战剂，都是手性的。它们是彼此不可重叠的镜像。分子的一只手可能是有效的药物，而另一只手可能是无效的，甚至是致命的。沙利度胺就是一个例子--一只手是镇静剂，另一只手会产生出生缺陷。在所提出的工作中，手性金属氧化物将通过电沉积来沉积，这是一种简单且廉价的方法。通过添加酒石酸和氨基酸等手性分子来控制薄膜的手性。这些手性薄膜将作为简单的手性分子和更复杂的药物的传感器进行测试。材料研究中心将为学生和博士后提供跨学科的研究环境。国际和平研究所有一个由化学家、物理学家、化学工程师和材料科学家组成的研究小组。学生们还将有机会与阿斯利康制药公司合作开发手性传感器。本科生研究是该项目的重要组成部分。每年为两名本科生研究人员提供资金。

Many biomolecules are chiral- they can exist in one of two enantiomeric forms that only differ in that their structures are mirror images of each other. Because one enantiomer tends to by physiologically active while the other is inactive or even toxic, drug compounds are increasingly produced in an enantiomerically pure form using solution-phase homogeneous catalysts and enzymes. Chiral surfaces offer the possibility of developing heterogeneous enantiospecific catalysts that can more readily be separated from the products and reused. In addition, such surfaces might serve as electrochemical sensors for chiral molecules - perhaps even implantable chiral sensors that could be used to monitor drug levels in the body. In the proposed work, chiral surfaces of metal oxides such as CuO, AgO, Bi2O3, PbO2, Tl2O3, Y2O3, and In2O3 will be electrodeposited onto achiral surfaces such as single crystal Au and Cu using chiral molecules such as tartaric acid and amino acids to direct the chirality. Surfaces will be electrodeposited which lack mirror or glide plane symmetry. It is not necessary for the materials to crystallize in a chiral space group. The absolute configuration of the films will be determined by X-ray pole figure analysis, and the microstructure will be probed by electron and scanning probe microscopy. The concept of electrochemical biomineralization will be explored by depositing calcite in the presence of chiral agents by electrochemically generating base in a solution of calcium bicarbonate. The mechanism of chiral electrodeposition will be explored to determine whether the chiral molecules simply template the surface or imprint it. The mechanism will be probed by in situ techniques like scanning tunneling microscopy, vibrational spectroscopy, and electrochemical quartz microbalance experiments. Finally, the chiral oxide surfaces will be used to produce chiral electrochemical sensors. These sensors will be screened for the chiral recognition of simple chiral molecules such as tartaric and amino acids, in addition to more complex pharmaceutical drugs.Chirality is ubiquitous in Nature. Many biomolecules, such as pharmaceuticals and chemical warfare agents are chiral. They are non-superimposable mirror images of each other. One hand of the molecule can be an effective drug, while the other hand can be ineffective or even lethal. Thalidomide is an example- one hand is a sedative, while the other hand produces birth defects. In the proposed work, chiral metal oxides will be deposited by electrodeposition, a simple and inexpensive method. The chirality of the films will be controlled by the addition of chiral molecules such as tartaric acid and amino acids. The chiral films will be tested as sensors for simple chiral molecules and more complex pharmaceutical drugs. Students and postdoctoral associates will be provided with an interdisciplinary research environment in the Materials Research Center. The PI has a research group consisting of chemists, physicists, chemical engineers, and materials scientists. The students will also have the opportunity to work with the pharmaceutical company AstraZeneca Corporation on the development of chiral sensors. Undergraduate research is an important part of the project. Funding is provided each year for two undergraduate student researchers.