Mass Spectrometric Studies of Spin Control in Open-Shell Molecules

开壳分子自旋控制的质谱研究

• 批准号: 0808964
• 负责人: Paul Wenthold
• 金额: $ 39万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2011-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0808964&HistoricalAwards=false
• 关键词: Mass; Spectrometric; Studies; Spin; Control

The project involves mass spectrometry studies of the thermochemical properties of the reactivity of open-shell molecules and ions. The proposal describes studies designed to investigate the mechanisms through which electrons can interact in open-shell systems. The goal of the work is to provide insight into how to control the spin of open-shell system by strategically choosing structural motifs that exploit the appropriate mechanistic aspects. The three methods of controlling spin are:1) Topological approaches : the focus of this area is on disjoint diradicals and using connectivity to create them in either triplet or singlet states. The role of topology will be investigated by contrasting the properties, such as electron affinities, of structurally related but topologically distinct bis-allylic diradicals.2) Heteroatom substitution : replacing a carbon in well-studied hydrocarbon diradicals with nitrogen or oxidized nitrogen can change the ground and excited state energy orderings. This effect will be investigated by examining the thermochemical properties of pyridine- and pyridine-n-oxide based diradicals, determined by using energy-resolved collision-induced dissociation studies.3) Substitution : the electronic state ordering of aromatic nitrenes is altered by using substituents either on the aromatic ring or next to the nitrene center. Negative ion photoelectron spectroscopy of substituted phenylnitrene radical anions will be used to investigate the electron affinities and the energies of the excited states in the neutral phenyl nitrenes.Gas-phase studies of reactivity and structure can impact all areas of chemistry as well as other disciplines such as material science and engineering. Mechanistic studies provide insight that can be used to develop new reactivity methodologies. Whereas structural studies of open-shell species such as diradicals and triradicals provide insight into bonding and reactivity, they also provide a foundation for engineering and material science approaches to magnetic materials. The work described in this proposal is also an important component of the education of a diverse and talented group of graduate students at Purdue University. This support also allows the PI to utilize his experience with the NSF Graduate Research Fellowship Program to encourage and activities of the undergraduate students in the local ACS Student Affiliates and Alpha Chi Sigma chapters, particularly in regards to developing creative ways for the students to serve and impact the community.

该项目涉及对开壳分子和离子反应性的热化学性质的质谱学研究。该提案描述了旨在调查电子在开壳系统中相互作用的机制的研究。这项工作的目标是为如何通过战略性地选择利用适当机械方面的结构主题来控制开壳系统的旋转提供洞察力。控制自旋的三种方法是：1)拓扑学方法：这一领域的重点是不相交的双自由基，并利用连接性在三重态或单重态中创建它们。拓扑的作用将通过对比结构上相关但拓扑上不同的双烯丙基双基的性质(如电子亲和力)来研究。2)杂原子替代：用氮或氧化氮取代研究充分的碳氢双基中的碳可以改变基态和激发态的能量顺序。这种影响将通过检测基于吡啶和吡啶-N-氧化物的双自由基的热化学性质来研究，通过能量分辨碰撞诱导解离研究。3)取代：通过在芳环上或在硝烯中心附近使用取代基来改变芳香族硝烯的电子态有序性。取代苯基硝基阴离子的负离子光电子能谱将被用来研究中性苯基硝基阴离子的电子亲和力和激发态的能量。气相反应性和结构的研究将影响到化学的所有领域以及其他学科，如材料科学和工程。机械论研究提供了可用于开发新的反应性方法的见解。虽然对开壳物种(如双自由基和三自由基)的结构研究提供了对成键和反应活性的洞察，但它们也为工程和材料科学方法处理磁性材料提供了基础。这项建议中描述的工作也是普渡大学培养多样化和有才华的研究生群体的重要组成部分。这种支持还允许PI利用他在NSF研究生研究奖学金计划的经验来鼓励和鼓励本科生在当地的ACS学生附属机构和阿尔法·奇西格玛分会开展活动，特别是在为学生开发创造性的方式来服务和影响社区方面。