CAS: Spectroscopy and Unimolecular Dynamics of Reaction Intermediates in Atmospheric Chemistry

CAS：大气化学反应中间体的光谱学和单分子动力学

基本信息

批准号：
2301298
负责人：
Marsha Lester
金额：
$ 60.5万
依托单位：
University of Pennsylvania
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2023
资助国家：
美国
起止时间：
2023-05-15 至 2026-04-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2301298&HistoricalAwards=false
关键词：
CAS Spectroscopy Unimolecular Dynamics Reaction

项目摘要

With support from the Chemical Structure, Dynamics, and Mechanisms A (CSDM-A) program in the Division of Chemistry, Professor Marsha Lester of the University of Pennsylvania and her team are using molecular spectroscopic and theoretical methods to study the unimolecular decay dynamics of carbonyl oxide intermediates generated through ozonolysis of alkenes. These reaction intermediates are an important source of hydroxyl radicals, which result in the oxidation of most volatile organic compounds, and are precursors to new particle formation in the atmosphere. Professor Lester and her students will investigate novel rearrangement mechanisms of the carbonyl oxide intermediates that lead to different products. These studies could lead to a better understanding of the generation of hydroxyl radicals in the atmosphere and other products that may impact on new particle formation. These studies will provide a stimulating environment for training and development of next generation scientists working at the interface between physical chemistry and atmospheric science.Professor Lester and her students will combine infrared laser activation of carbonyl oxide intermediates with time-resolved detection of hydroxyl radical products utilizing laser-induced fluorescence to measure unimolecular decay rates and provide direct insight on transition state barriers leading to products. The planned experimental studies and theoretical modeling will examine unimolecular decay processes of carbonyl oxide intermediates via 1,3 ring closure mechanisms. Extension to carbonyl oxides with greater carbon chain length and/or heteroatom substitution will be explored, which may lead to new low energy pathways with the potential for ring closure and secondary ozonide formation. Additional studies will implement various laser spectroscopic techniques to identify and characterize alternative products resulting from intra-fragment roaming reactions in the unimolecular decay of carbonyl oxide intermediates. In this case, the separating hydroxyl radical can reorient and roam at long-range, potentially leading to a wide range of products via addition and/or abstraction reactions, which may impact the yield of hydroxyl radicals.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.

在化学系化学结构、动力学和机理 A (CSDM-A) 项目的支持下，宾夕法尼亚大学的 Marsha Lester 教授和她的团队正在利用分子光谱和理论方法研究羰基的单分子衰变动力学通过烯烃的臭氧分解产生的氧化物中间体。这些反应中间体是羟基自由基的重要来源，羟基自由基会导致大多数挥发性有机化合物的氧化，并且是大气中新颗粒形成的前体。莱斯特教授和她的学生将研究产生不同产物的羰基氧化物中间体的新颖重排机制。这些研究可以使人们更好地了解大气中羟基自由基的产生以及可能影响新颗粒形成的其他产物。这些研究将为在物理化学和大气科学之间工作的下一代科学家的培训和发展提供一个刺激的环境。莱斯特教授和她的学生将利用红外激光活化羰基氧化物中间体与羟基自由基产物的时间分辨检测相结合激光诱导荧光可测量单分子衰减率并提供对产生产品的过渡态势垒的直接了解。计划的实验研究和理论模型将通过 1,3 闭环机制检查羰基氧化物中间体的单分子衰变过程。将探索扩展到具有更大碳链长度和/或杂原子取代的羰基氧化物，这可能导致新的低能途径，具有闭环和二次臭氧化物形成的潜力。其他研究将采用各种激光光谱技术来识别和表征羰基氧化物中间体单分子衰变中片段内漫游反应产生的替代产物。在这种情况下，分离的羟基自由基可以重新定向并长距离漫游，可能通过加成和/或抽象反应产生多种产物，这可能会影响羟基自由基的产率。该奖项反映了 NSF 的法定使命，并具有通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Roaming in the Unimolecular Decay of syn -Methyl-Substituted Criegee Intermediates

顺式甲基取代的 Criegee 中间体的单分子衰变中的漫游

DOI：
10.1021/acs.jpca.3c05859
发表时间：
2023-12
期刊：
The Journal of Physical Chemistry A
影响因子：
0
作者：
Liu, Tianlin;Lester, Marsha I.
通讯作者：
Lester, Marsha I.

Bimolecular Reaction of Methyl-Ethyl-Substituted Criegee Intermediate with SO 2

甲基乙基取代的 Criegee 中间体与 SO 2 的双分子反应

DOI：
10.1021/acs.jpca.3c04648
发表时间：
2023-11
期刊：
The Journal of Physical Chemistry A
影响因子：
0
作者：
Zou, Meijun;Liu, Tianlin;Vansco, Michael F.;Sojdak, Christopher A.;Markus, Charles R.;Almeida, Raybel;Au, Kendrew;Sheps, Leonid;Osborn, David L.;Winiberg, Frank A.;et al
通讯作者：
et al

OH Roaming and Beyond in the Unimolecular Decay of the Methyl-Ethyl-Substituted Criegee Intermediate: Observations and Predictions

甲基乙基取代的 Criegee 中间体的单分子衰变中的 OH 漫游和超越：观察和预测

DOI：
10.1021/jacs.3c07126
发表时间：
2023-09
期刊：
Journal of the American Chemical Society
影响因子：
15
作者：
Liu, Tianlin;Elliott, Sarah N.;Zou, Meijun;Vansco, Michael F.;Sojdak, Christopher A.;Markus, Charles R.;Almeida, Raybel;Au, Kendrew;Sheps, Leonid;Osborn, David L.;et al
通讯作者：
et al

A five-carbon unsaturated Criegee intermediate: synthesis, spectroscopic identification, and theoretical study of 3-penten-2-one oxide

五碳不饱和Criegee中间体：3-戊烯-2-酮氧化物的合成、光谱鉴定及理论研究