Photochemistry, Spin, and Molecular Motion: Connections through Magnetic Resonance

光化学、自旋和分子运动：通过磁共振连接

• 批准号: 1464817
• 负责人: Malcolm Forbes
• 金额: $ 54万
• 依托单位: Bowling Green State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-15 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1464817&HistoricalAwards=false
• 关键词: Photochemistry; Spin; Molecular; Motion; Connections

With this award, the Chemical Structure, Dynamics and Mechanisms B (CSDM-B) Program of the Division of Chemistry is funding Professor Malcolm D. E. Forbes at Bowling Green State University to study how molecules move in confined spaces on the nanometer scale. With specially designed spectroscopic measurements, the Forbes laboratory investigates the location and mobility of molecules confined to thin polymer films, such as those making up household paint coatings, as well as other structures like microbubbles, which are used as delivery vehicles for cancer therapy. Recently, this group has applied these techniques to study a class of materials called "structured fluids." These fluids have many practical applications in the food and oil industries, but the underlying fundamental principles describing the flow of these materials under stress is poorly understood. Forbes and his coworkers are attempting to provide a rigorous quantitative footing for how the viscosities of structured liquids change in response to a stress. Dr. Forbes co-chairs the 2015 Gordon Research Conference on Photochemistry and he currently serves as President of the Inter-American Photochemical Society (I-APS), working with the Society to promote UNESCO?s "Year of Light" in 2015. The Forbes laboratory uses steady-state and time-resolved electron paramagnetic resonance (SSEPR and TREPR) spectroscopies at multiple frequencies, coupled to pulsed lasers or continuous wavelength (CW) light sources to create photogenerated radical pairs in confined environments such as vesicles and in heterogeneous media such as non-Newtonian fluids. With rigorous spectral simulation routines, the group is able to extract structural data (hyperfine couplings and exchange interactions), kinetic parameters (rate constants and activation energies), and molecular dynamics information. Systems currently under investigation include: 1) singlet oxygen reactivity and topology in heterogeneous structures (micelles and vesicles), 2) polymer chain dynamics in solutions, emulsions, and thin films, 3) coordination compounds such as light-harvesting copper complexes and water-splitting ruthenium catalysts, and 4) the molecular basis of rheological phenomena such as viscosity modification. The well-established "nanoreactor model" for the TREPR line shapes of mobile spin correlated radical pairs (SCRPs) is being refined for radicals located in colloidal systems such as pluronic micelles and mixed surfactant vesicles. These experiments provide detailed information about the mobility and ordering of small molecules over a wide range of time scales.The Forbes laboratory has strong interactions with scientists from overseas (Russia, Mexico, China and Austria).

有了这个奖项，化学系的化学结构，动力学和机制B（CSDM-B）计划资助教授马尔科姆D。E.福布斯在鲍林绿色州立大学，研究如何分子移动在有限的空间在纳米尺度。通过专门设计的光谱测量，福布斯实验室研究了局限于薄聚合物膜的分子的位置和流动性，例如那些构成家用油漆涂层的分子，以及其他结构，如微泡，它们被用作癌症治疗的运载工具。最近，这个小组已经应用这些技术来研究一类被称为“结构流体”的材料。“这些流体在食品和石油工业中有许多实际应用，但描述这些材料在压力下流动的基本原理却知之甚少。福布斯和他的同事们正试图为结构液体的粘度如何响应应力而变化提供一个严格的定量基础。福布斯博士是2015年戈登光化学研究会议的联合主席，他目前担任美洲光化学学会（I-APS）的主席，与该学会合作促进联合国教科文组织？2015年的“光之年”福布斯实验室在多个频率下使用稳态和时间分辨电子顺磁共振（SSEPR和TREPR）光谱，与脉冲激光或连续波长（CW）光源耦合，以在封闭环境（如囊泡）和非均匀介质（如非牛顿流体）中产生光生自由基对。通过严格的光谱模拟程序，该小组能够提取结构数据（超精细耦合和交换相互作用），动力学参数（速率常数和活化能）和分子动力学信息。目前正在研究的系统包括：1）单线态氧反应性和拓扑结构的异质结构（胶束和囊泡），2）聚合物链动力学的溶液，乳液和薄膜，3）配位化合物，如捕光铜配合物和水裂解钌催化剂，和4）流变现象的分子基础，如粘度调节。完善的“纳米反应器模型”的TREPR线形状的移动的自旋相关的自由基对（SCRPs）正在完善的自由基位于胶体系统，如普朗尼克胶束和混合的表面活性剂囊泡。福布斯实验室与来自海外（俄罗斯、墨西哥、中国和奥地利）的科学家有很强的互动。