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

在这个由化学系的化学结构、动力学和机制项目资助的项目中，威斯康星大学欧克莱尔分校的詹姆斯菲利普斯教授和他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;当物质冷凝或进入溶液时，原子之间的距离通常不会改变。然而，某些“分子复合物”--两个或多个稳定分子的结合--可能会发生类似的重大变化，但这种效应的总体普遍性还没有得到很好的确立。该项目将描述一系列易于在惰性、非相互作用的“溶剂”环境中改变结构的复合物，称为“低温基质”（氩、氖或氮的固体样品，在接近绝对零度的温度下冷冻）。这些复合物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，当结构发生变化时，这些频率会系统地发生变化。此外，将通过计算机模拟键合来探索这些系统，以解决驱动不寻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对化学键合性质的基本理解，这反过来又可以帮助其他研究人员更好地理解和预测研究实验室，工业环境和环境中的化学反应性。 该项目将在一所可访问的公立综合大学（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。这种结合量子化学和实验（矩阵-IR和UV光谱）研究将针对三种类型的系统：i）H3 N-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SO 3络合物。核心假设是SOx中中心S原子周围的键将表现出阻碍进一步配位的排斥力，并导致惰性介质中的极端结构变化。这一点的确认将表明对影响配位键强度的因素的精确理解，这可能会影响化学的许多领域。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

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.