RUI: Theoretical Studies of Non-Covalent Interactions and Chemical Bonding Transitions Across Phases in Inorganic Systems, and Investigations of Other Modes of Weak Bonding

在这个由化学系化学结构动力学和机制-A（CSDM-A）项目资助的项目中，里士满大学的Kelling Donald教授正在使用理论方法来理解化学系统中分子之间的相互作用，特别是弱相互作用很重要。 在现代化学中众所周知，原子和分子可以以非常强烈的方式相互作用以形成新的化合物，并且以更容易逆转或破坏的弱方式相互作用。 然而，对于后一种情况，即使相互作用相对较弱，它们也可能非常重要。 例如，弱相互作用使壁虎能够爬墙，并在自然界和研究实验室中产生其他可证明的影响。 该项目研究弱相互作用至关重要的化学系统。 这样的体系包括金属卤化物类的化合物，其在某些情况下形成通过弱相互作用稳定的固体，但在其他情况下不稳定。 该项目部分致力于阐明为什么某些金属卤化物的固体在某些情况下只能通过弱相互作用结合在一起，但这些弱相互作用在其他金属卤化物中被更强大的力量所取代。 重点是使用数学和计算工具，以进一步了解弱相互作用如何过渡到强化学键，从而更好地预测新的和有趣的材料特性。 该项目将使本科生和学士后学生参与教师指导的研究，并为来自不同背景的高中生提供指导研究经验，并帮助他们获得在大学取得成功的关键学术技能。该项目在里士满大学（UR）的Kelling Donald教授的指导下进行目的在于使键合转变现象合理化，其中化学体系如二元二卤化物二氟化汞在低聚过程中从簇中的弱货车范德华型键合移动到极性单体间共价键合，最终会聚在离子固体结构上。 这些研究的目的是阐明这一现象的基本基础和演变，它存在于卤化物，卤化物和氧化物的其他重主族和d-区金属。唐纳德小组还将研究相对论效应在这些现象中的作用。另一类弱相互作用是卤素键和其他所谓的σ空穴相互作用，它们继续与生物学和有机卤化物的晶体工程有关。 这项工作的一个目标是促进对有机和无机卤化物的这种现象的理解，以及系统中的其他不寻常的键合模式，如fluxional有机金属和潜在的ouroboric环化合物。 唐纳德教授的本科生将执行大部分拟议的工作，来自不同背景的高中生将参加唐纳德教授设计的研究/指导计划，该计划将侧重于吸引来自代表性不足的群体的高中三年级学生和潜在的第一代大学生（i）UR研究实验室的实践活动，（ii）与大学专业人员就学习技能、压力管理和其他关键能力进行直接讨论，以及（iii）夏季研究奖学金。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

In this project funded by the Chemical Structure Dynamics and Mechanisms-A (CSDM-A) program of the Chemistry Division, Professor Kelling Donald of the University of Richmond is using theoretical methods to understand the interactions between molecules in chemical systems where particularly weak interactions are important. It is well-known in modern chemistry that atoms and molecules can interact with each other in very strong ways to form new compounds and in weak ways that can be more readily reversed or disrupted. For the latter case, however, even though the interactions are relatively weak, they can be very important. Weak interactions allow geckos to climb walls, for instance, and have other demonstrable effects in nature, and in research laboratories. This project investigates classes of chemical systems where weak interactions are crucial. Such systems include compounds of the metal halide class that form solids stabilized by weak interactions, in some cases, but not in other cases. The project is dedicated in part to elucidating why the solids of some metal halides are held together only by weak interactions in certain cases, but those weak interactions are overtaken by much more powerful forces in other metal halides. The focus is on using mathematical and computational tools to further our understanding of how weak interactions transition to strong chemical bonding and, in turn, to better predict new and interesting materials properties. This project will engage undergraduates and post-baccalaureate students in faculty-guided research and provide high school students from diverse backgrounds with mentored research experiences, and help them to acquire academic skills that are crucial for success in college.This project under the guidance of Professor Kelling Donald at the University of Richmond (UR) aims to rationalize the bonding transition phenomenon in which chemical systems such as the binary dihalide mercury difluoride, move during the oligomerization process from weak van der Waals-type bonding in clusters to polar covalent inter-monomer bonding, eventually converging upon an ionic solid structure. These studies are aimed at elucidating the fundamental basis and the evolution of this phenomenon where it exists among the halides, hydrides, and oxides of other heavy main group and d-block metals. The Donald group will also examine the role of relativistic effects in these phenomena. Another class of weak interactions under examination here is halogen bonding and other so-called sigma hole interactions, which continue to be implicated in biology and in the crystal engineering of organohalides. A goal in this work is to advance understanding of that phenomenon for organic and inorganic halides, and other unusual bonding modes in systems such as fluxional organometallic and potential ouroboric ring compounds. Professor Donald’s undergraduate students will perform the majority of the proposed work, and high school students from diverse backgrounds will participate in a research/mentoring program devised by Professor Donald, which will focus on attracting high school juniors from underrepresented groups and potential first-generation college students for (i) hands-on activities in research labs at UR, (ii) direct discussions with UR professionals on study skills, stress management, and other key competencies, and (iii) summer research fellowships.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.