Thermochemistry of Metal-Ligand Bonds and Protonated Peptides

在化学系化学结构、动力学和机理a （CSDM-A）项目的支持下，犹他大学的Peter B. Armentrout教授和他的团队将使用一种结合电喷雾、流管和离子迁移源的引导离子束串联质谱计来研究气相有机金属和生物离子化学。这些研究将试图研究与量化过渡金属阳离子的激发态化学和确定生物分子离子特定构象之间的绝对能量差异相关的复杂挑战。Armentrout教授和他的学生将研究碰撞诱导解离实验中的角动量效应，过渡金属（TM）离子的状态特异性化学，质子化肽及其结构分解的能量学，以及由过渡金属激活涉及甲烷和更大碳氢化合物的C-H键形成的物种。他们的研究可以更好地理解过渡金属离子反应中的自旋轨道耦合效应，肽降解过程，特别是构象特异性能量学，以及工业上重要的C-H键激活和C-C偶联过程。除了对科学产生更广泛的影响外，所开展的工作还将进一步促进科学、技术、工程和数学（STEM）劳动力的教育，包括研究生和本科生。根据这项奖励，犹他大学的亚美尼亚特劳特小组将研究几个相互关联的领域；最近开发的IM源将通过增加新型离子源和紧凑的SLIM（无损离子操作结构）设备来增强分辨率。IM源将用于研究TM离子的状态特异性化学和特定构象的质子化肽分解的能量学。后一种过程对于理解蛋白质序列鉴定的分析应用非常重要，并将首次通过实验建立真正的地面构象。聚焦系统将包括那些含有天冬酰胺的系统，其中脱酰胺被认为是导致衰老和神经退行性疾病发病的主要分子过程。红外作用光谱将用于确定生物体系的结构，以及探测由TM阳离子与碳氢化合物的CH键激活和CC偶联反应形成的物种结构。所有研究领域都将辅以理论计算。潜在的变革性研究包括自旋轨道耦合效应的定量表征，构象之间能量差异的绝对测量，以及甲烷活化过程。在所有这些努力中，这些研究将提供热力学数据并培养未来的科学家。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) program in the Division of Chemistry, Professor Peter B. Armentrout and his group at the University of Utah will use a guided ion beam tandem mass spectrometer coupled with electrospray, flow tube, and ion mobility sources to study gas-phase organometallic and biological ion chemistry. These studies will seek to examine the complex challenges associated with quantifying the chemistry of excited electronic states of transition metal cations and determining absolute energies differences between specific conformations of biomolecular ions. Professor Armentrout and his students will investigate angular momentum effects in collision-induced dissociation experiments, state-specific chemistry of transition metal (TM) ions, energetics for decomposition of protonated peptides along with their structures, as well as species formed by transition metal activation of C-H bonds involving methane and larger hydrocarbons. Their studies could lead to better understandings of spin-orbit coupling effects in reactions of transition metal ions, peptide degradation processes especially for conformation-specific energetics, and industrially important C-H bond activation and C-C coupling processes. In addition to these broader impacts in science, the work performed will also further the education of an informed science, technology, engineering, and mathematics (STEM) workforce, including both graduate and undergraduate students. Under this award, the Armentrout group at the University of Utah will examine several interrelated areas; a recently developed IM source will be enhanced by the addition of novel ion sources and a compact SLIM (structures for lossless ion manipulation) device for enhanced resolution. The IM source will be used to study state-specific chemistry of TM ions and the energetics for decomposition of conformer-specific protonated peptides. The latter processes are important in understanding analytical applications for protein sequence identification and will experimentally establish the true ground conformer for the first time. Systems of focus will include those containing asparagine, where deamidation is believed to be a major molecular process contributing to aging and the onset of neurodegenerative diseases. Infrared action spectroscopy will be used to determine structures of biological systems as well as to probe structures of species formed by CH bond activation and CC coupling reactions of TM cations with hydrocarbons. All areas of study will be complemented by theoretical calculations. Potentially transformative studies include quantitative characterization of spin-orbit coupling effects, absolute measurements of energy differences between conformations, and methane activation processes. In all these endeavors, the studies will provide thermodynamic data and educate future scientists.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.