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CAREER: Advancing the Mechanistic Understanding of Naphthopyran Mechanochemistry

职业：推进对萘并吡喃机械化学的机理理解

基本信息

批准号：
2145791
负责人：
Maxwell Robb
金额：
$ 65万
依托单位：
California Institute of Technology
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-03-01 至 2027-02-28
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2145791&HistoricalAwards=false
关键词：
CAREER Advancing Mechanistic Understanding Naphthopyran

项目摘要

With the support of the Macromolecular, Supramolecular and Nanochemistry (MSN) and Chemical Structure, Dynamics and Mechanisms-B (CSDM-B) programs in the Division of Chemistry, Maxwell J. Robb of the California Institute of Technology (Caltech) is advancing the understanding of the chemical reactivity of mechanophores embedded within long chain macromolecules or polymers. Mechanophores are organic compounds that undergo chemical transformations in response to external mechanical force. When incorporated into polymer chains, they can act as sensors and provide valuable information about the behavior of polymers under stress. This characteristic of mechanophores is important in guiding future design of stimuli-responsive polymers with applications in a variety of areas including adhesives, sensors, drug delivery, and sustainability. In this research, experimental and computational techniques will be used to systematically study the chemistry of mechanophores that change color when exposed to stress. Reactivity will be analyzed and correlated with the chemical structure of the mechanophore to understand and control response when exposed to external stress. The synthesized molecules will be incorporated into polymers to design unique responsive materials that change color under stress. Several educational initiatives will be integrated with the research to broaden participation and enable training of undergraduate and graduate students in polymer chemistry, as well as physical and synthetic organic chemistry. Summer research experiences will support the scientific development of undergraduate students from underrepresented groups majoring in chemistry. In addition, a hands-on polymer mechanochemistry module will be integrated into K-12 outreach programs in collaboration with the Center for Learning, Teaching, and Outreach at Caltech. This activity will engage numerous members of the Pasadena community each year and introduce important concepts related to polymers and materials chemistry. Lastly, a webinar series will be developed to educate students about the different career paths available in chemistry to help to build the next generation of scientists.This research will focus on the development of an improved mechanistic understanding of the mechanochemical reactivity of naphthopyran mechanophores. Comprehensive mechanistic and activity studies will be performed to determine the effect of substituents on the mechanochemical ring-opening reaction of naphthopyran by establishing linear free energy relationships. These studies will be complemented by computation to provide detailed insights into the mechanism of merocyanine formation under force. Additionally, the Robb team will work toward developing a detailed understanding of force-coupled merocyanine isomerization, which is a critical component of naphthopyran mechanochemistry. An improved fundamental understanding of structure-reactivity relationships in these systems would serve to guide the development of bis-naphthopyran mechanophores that achieve distinct ring-opening reactions under varying mechanical loads in polymers, leading to different merocyanine states with uniquely coupled visual responses. This project has the potential to advance knowledge of mechanochemical reactivity and empower innovation in the rapidly expanding field of polymer mechanochemistry and in related cross-cutting disciplines.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.

在化学系大分子、超分子和纳米化学(MSN)和化学结构、动力学和机理B(CSDM-B)计划的支持下，加州理工学院(Caltech)的Maxwell J.Robb正在推动对嵌入长链大分子或聚合物中的机械团的化学反应能力的理解。机械团是一种在外力作用下发生化学变化的有机化合物。当被结合到聚合物链中时，它们可以充当传感器，并提供关于聚合物在压力下的行为的有价值的信息。机械载体的这一特性对于指导未来刺激响应性聚合物的设计具有重要意义，这些聚合物的应用领域包括粘合剂、传感器、药物输送和可持续性。在这项研究中，实验和计算技术将被用来系统地研究当暴露在压力下时会改变颜色的机械团的化学。将分析反应性，并将其与机械团的化学结构相关联，以了解和控制暴露在外部压力下的反应。合成的分子将被结合到聚合物中，以设计独特的响应材料，在压力下会改变颜色。几项教育举措将与研究相结合，以扩大参与，并使本科生和研究生能够在聚合物化学以及物理和合成有机化学方面进行培训。暑期研究经验将支持化学专业未被充分代表的本科生的科学发展。此外，将与加州理工大学学习、教学和推广中心合作，将动手操作的聚合物机械力化学模块整合到K-12推广计划中。这项活动每年将吸引帕萨迪纳社区的许多成员参与，并介绍与聚合物和材料化学有关的重要概念。最后，将举办一系列网络研讨会，教育学生了解化学领域可用的不同职业道路，以帮助培养下一代科学家。这项研究将集中于提高对萘并吡喃机械团的机械力化学反应的理解。通过建立线性自由能关系，对取代基对萘并吡喃的机械力化学开环反应的影响进行了全面的机理和活性研究。这些研究将得到计算的补充，以提供关于花菁在力作用下形成机理的详细见解。此外，Robb团队将致力于发展对力偶联花菁异构化的详细了解，这是萘并吡喃机械力化学的关键组成部分。对这些体系中结构-反应性关系的更好的基础理解将有助于指导双萘并吡喃机械团的开发，这些机械团在聚合物中不同的机械载荷下实现不同的开环反应，导致具有独特耦合视觉响应的不同的花菁状态。该项目有可能促进机械力化学反应的知识，并促进在迅速发展的聚合物机械力化学领域和相关交叉学科中的创新。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。