Achieving the Full Phase Space of Inorganic Natural Products and Beyond in Nanocrystal Synthesis

大自然通过地质学创造了一系列振奋人心的晶体，具有广泛的特性(颜色、孔隙度和机械强度等)。不同类型的晶体之所以具有独特的性质，不仅是因为它们的化学成分，而且是因为组成原子的精确和特定的排列。作为纳米晶体(尺寸仅为一缕头发宽度的1/1000倍)，这些不同的特性可能导致应用范围远至地球上丰富而活跃的工业催化剂、新的癌症治疗方法、磁性存储介质、更好的电池和廉价而高效的太阳能电池板。在这一切成为可能之前，必须首先发现在纳米级合成这些晶体的路线，因为极端的地质条件不容易在化学实验室或工业设施中复制。范德比尔特大学珍妮特·麦克唐纳教授的研究小组试图了解如何控制原子在纳米级岩石中的精确位置。实验的目的是询问有机分子和金属原子在反应时会发生什么，以及如何控制原子在这些纳米尺寸的岩石中的精确位置。最终目标是制造出地质学所能做到的晶体的所有相，并有可能设计和制备具有新相的晶体。该项目还研究了美国和加拿大的土著Anishinaabe人的岩画中，小块氧化铁颜料的表面是如何结合到花岗岩表面的，这些岩画非常耐用。这里的目标是重新发现丢失的岩石艺术技术，并将其归还给Anishinaabe。该项目支持对高中、本科生和研究生各级研究人员的培训。已建立的和新的联系鼓励Anishinaabe研究人员参与这项研究。具体地说，该项目使用含有硫和硒原子的有机分子库作为前体，以获得由这些材料制成的各种晶体。对铁、钴、镍和铜硫化物纳米晶的相控合成进行了广泛、全面和系统的研究。有机硫族化合物的库被用来将动力学速率的作用与相确定中的分解机制分开。识别有机反应产物，以破译有机硫化物在金属上的分解机理，并推断这些机理对相控制的影响。在第二个目标中，有机硒和二硒醚化学促进了过渡金属硫族化合物的多型选择。利用纳米晶体反应的原位溶液~1H和~(77)Se核磁共振谱，研究了有机硫化物化学对纳米晶体合成中多型性的影响。最后，我们研究了赤铁矿颜料与二氧化硅在不同应用条件下的粘附性，这些应用条件是通过实验室化学物质精确控制的。将这些研究翻译成自然来源的材料如下。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nature, through geology, has created an inspiring array of crystals with a wide range of properties (color, porosity, and mechanical strength, etc.). The unique properties of different types of crystals are a result of not only their chemical compositions, but also the precise and specific arrangement of the constituent atoms. As nanosized crystals (of dimensions of only about 1/1000 times the width of a strand of hair), these diverse properties could lead to applications as far reaching as earth abundant and active industrial catalysts, new cancer treatments, magnetic storage media, better batteries, and inexpensive and efficient solar panels. Before any of this is possible, the routes to synthesize these crystals at the nanoscale must first be discovered because the extreme conditions of geology cannot be easily replicated in the chemistry laboratory or industrial facilities. The research group of Professor Janet Macdonald at Vanderbilt University seeks to understand how the precise placements of atoms in nano-sized rocks can be controlled. Experiments are designed to interrogate what happens to organic molecules and metal atoms when they react and how to control the precise placement of atoms in these nano-sized rocks. The ultimate goal is to make all the phases of crystals that geology does, and possibly be able to design and prepare crystals with new phases. The project also examines how the surfaces of small pieces of iron oxide pigments bind to granite surfaces in the remarkably durable rock paintings of the Anishinaabe, an indigenous people of the United States and Canada. The goal here is to rediscover the lost technique for rock art and return it to the Anishinaabe. The project supports the training of researchers in high school, undergraduate and graduate student levels. Established and new connections encourage Anishinaabe researchers to take part in the research. Specifically, this project uses libraries of organic molecules that contain sulfur and selenium atoms as precursors to obtain the diverse crystals made of these materials. A wide, sweeping and systematic study of the phase-controlled synthesis of iron, cobalt, nickel and copper chalcogenide nanocrystals is being performed. Libraries of organochalcogenides are employed to separate the roles of kinetic rates from the decomposition mechanisms in phase-determination. Organic reaction products are identified to decipher the mechanisms of decomposition of the organochalcogenides on the metals and deduce the impact of these mechanisms on phase control. In a second aim, organoselenol and diselenide chemistry facilitates polytypic selection in the transition metal chalcogenides. In situ solution 1H and 77Se NMR spectroscopy of nanocrystal reactions are used to understand how the organochalcogenide chemistry influences the polytypism in nanocrystal synthesis. In the final thrust, adherence of hematite pigments to silica is studied under varied application conditions precisely controlled using laboratory chemicals. Translation of these studies to naturally sourced materials follows.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.