RUI: Condensed-Phase Effects on the Structural and Energetic Properties of Nitrogen Donor - SOx Complexes

在这个由化学结构、动力学和机制--化学系的一个项目资助的项目中，詹姆斯·菲利普斯教授和他在威斯康星大学Eau Claire分校的本科研究人员将研究某些稳定分子的结构如何由于它们相互关联而发生变化。分子结构通常不受化学环境的影响；当一种物质凝结或进入溶液时，原子之间的距离通常不会改变。然而，某些“分子复合体”--两个或更多稳定分子的缔合--可以经历这类分子的重大变化，但这种效应的总体共性还没有得到很好的确立。该项目将描述一系列在惰性、非相互作用的“溶剂”环境中易于改变结构的络合物，称为“低温基质”(在接近绝对零度的温度下冻结的固态Ar、Ne或N的样品)。人们将通过探测它们的共振频率(它们的化学键振动的速度或容易程度)来研究这些配合物，当结构发生变化时，这些频率会发生系统性的变化。此外，将通过计算机模拟键合来探索这些系统，以解决驱动异常结构变化的潜在因素。从这些研究中获得的知识将有助于从根本上了解化学键的性质，这反过来又可以帮助其他研究人员更好地了解和预测研究实验室、工业环境和环境中的化学反应。该项目将在一所无障碍的公立综合性大学(UW-Eau Claire)进行，并将为本科生提供变革性的研究、指导和职业发展经验。这种量子化学和实验相结合(矩阵-IR和UV光谱)的研究将针对三种类型的体系：I)H3N-SO2及其甲基化类似物，II)吡啶-SO2及其氟吡啶类似物，以及III)类似的SO3络合物。中心假设是，SOX中中心S原子周围的键将表现出排斥力，阻碍进一步的配位，并导致惰性介质中的极端结构变化。对这一点的确认将表明对影响协调键强度的因素的精细理解，这可能会影响许多化学领域。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。

In this project funded by the Chemical Structure, Dynamics and Mechanisms-A program of the Chemistry Division, Professor James Phillips and his undergraduate researchers at the University of Wisconsin-Eau Claire will study how the structures of certain stable molecules change as a result of their associations with each other. Molecular structure is typically unaffected by chemical environment; distances between atoms typically do not change when a substance condenses or goes into solution. However, certain “molecular complexes” - associations of two or more otherwise stable molecules - can undergo major changes of this ilk, but the overall generality of such effects is not well-established. This project will characterize a series of complexes apt to change structure in inert, non-interacting “solvent” environments known as “cryogenic matrices” (solid samples of argon, neon, or nitrogen, frozen at temperatures near absolute zero). The complexes will be studied by probing their resonant frequencies (how fast or easily their chemical bonds vibrate), which shift systematically when structural changes occur. In addition, the systems will be explored by computer simulations of the bonding to address the underlying factors that drive the unusual structural changes. The knowledge gained from these studies will contribute to a fundamental understanding of the nature of chemical bonding, which in turn can help other researchers to better understand and predict chemical reactivity in the research lab, industrial settings, and the environment. The project will take place at an accessible, public comprehensive university (UW-Eau Claire), and will provide transformative research, mentoring, and career development experiences for undergraduate students. This combined quantum-chemical and experimental (matrix-IR and UV spectroscopic) investigation will target three types of systems: i) H3N–SO2 and its methylated analogs, ii) Pyridine - SO2, and its fluoropyridine analogs, and, iii) the analogous SO3 complexes. The central hypothesis is that bonds about the central S-atom in SOx will manifest repulsive forces that impede further coordination, and lead to extreme structural changes in inert media. Confirmation of this will manifest a refined understanding of factors affecting coordinate bond strength, which may impact many areas of chemistry.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.