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

化学系化学结构、动力学和机理B(CSDM-B)项目获得这一奖项，资助鲍林格林州立大学的马尔科姆·D·E·福布斯教授在纳米尺度上研究分子如何在受限空间中运动。通过特别设计的光谱测量，福布斯实验室研究了限制在聚合物薄膜中的分子的位置和流动性，比如构成家用涂料的分子，以及用作癌症治疗载体的微泡等其他结构。最近，这个小组应用这些技术研究了一类被称为“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鲜为人知。福布斯和他的同事正试图为结构性液体的粘度如何随压力变化提供一个严格的量化基础。福布斯博士是2015年戈登光化学研究会议的联合主席，目前担任美洲光化学学会主席，与该学会合作，推动联合国教科文组织？S在2015年的光年活动。福布斯实验室使用多个频率的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，在受限环境(如小泡)和非牛顿流体(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)多相结构(胶束和小泡)中的单线态氧反应性和拓扑结构；2)溶液、乳液和薄膜中的高分子链动力学；3)捕光铜络合物和水裂解Ru催化剂等配位化合物；以及4)粘度调整等流变现象的分子基础。对于Pluronic胶束和混合表面活性剂囊泡等胶体体系中的自由基，已建立的移动自旋相关自由基对(SCRP)TREPR线形的良好“纳米反应器模型”正在进行改进。这些实验提供了关于小分子在广泛时间范围内的流动性和有序性的详细信息。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。

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).