Dynamics and Mechanisms of Electron Delocalization over Supramolecular Mixed Valence Systems

超分子混合价体系电子离域动力学和机制

• 批准号: 1759460
• 负责人: Clifford Kubiak
• 金额: $ 17万
• 依托单位: University of California-San Diego
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1759460&HistoricalAwards=false
• 关键词: Dynamics; Mechanisms; Electron; Delocalization; over

In this project, supported by the Chemical Structure, Dynamics & Mechanism B Program of the Chemistry Division, Professor Clifford Kubiak of the Department of Chemistry at the University of California, San Diego (UCSD) is developing new classes of inorganic materials for use in next generation computers. The goal of this research is to develop and study new complexes that undergo picosecond (a trillionth of a second) electron transfer or structural rearrangements that occur in electronic grounds states. Such ultrafast molecular changes may be used to make novel molecular devices including those for information storage. This project has the potential to impact the broader scientific and engineering communities involved in electronic device technologies where a critical goal is to extend information processing by the current Complementary Metal-Oxide-Semiconductor (CMOS) platforms. The Kubiak group is well-positioned to provide a highly technical level of education and training for students. Outreach activities involving K-12 students, especially those from the Preuss School at UCSD and Torrey Pines High School. The focus of the project is the investigation of ultrafast (picosecond) electron transfer in mixed valence systems. Mixed-valent complexes typically consist of two identical redox active centers that are separated by a bridge. In their mixed-valent state, the redox centers differ only in their oxidation states and are stabilized relative to disproportionation by electron self-exchange. The group has showed that when the bridging interaction is composed of a hydrogen bond, electron transfer (ET) in the mixed-valent state stabilizes hydrogen-bonding interactions by about 5 kcal per mole relative to the neutral, isovalent, hydrogen-bonded dimers. A core question of this project is whether the hydrogen bond precedes, follows, or occurs in concert with ET. The specific goals are: to develop a complete physical description of how ET occurs across hydrogen bonds; to continue the synthesis of new complexes to better understand the interplay between electron delocalization and hydrogen bonding; and to investigate the switched-on self-assembly of supramolecular structures that can form stronger hydrogen bonds when reduced. A collaboration with a 2-dimensional infrared spectroscopy lab (2D IR) provides new spectroscopic insights into the dynamics and mechanisms of ET and molecular rearrangements that occur in ultrafast ground state molecules.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.

在该项目中，在化学系化学结构、动力学和机理 B 项目的支持下，加州大学圣地亚哥分校 (UCSD) 化学系的 Clifford Kubiak 教授正在开发用于下一代计算机的新型无机材料。 这项研究的目标是开发和研究在电子基态中发生皮秒（万亿分之一秒）电子转移或结构重排的新复合物。 这种超快的分子变化可用于制造新颖的分子设备，包括用于信息存储的分子设备。该项目有可能影响电子设备技术领域更广泛的科学和工程界，其关键目标是通过当前的互补金属氧化物半导体 (CMOS) 平台扩展信息处理。 Kubiak 集团处于有利地位，可以为学生提供高技术水平的教育和培训。 外展活动涉及 K-12 学生，特别是来自加州大学圣地亚哥分校普鲁斯学校和多利松高中的学生。该项目的重点是研究混合价系统中的超快（皮秒）电子转移。混合价复合物通常由两个相同的氧化还原活性中心组成，并由桥隔开。在混合价态下，氧化还原中心仅在氧化态上有所不同，并且相对于通过电子自交换的歧化作用而言是稳定的。该小组表明，当桥联相互作用由氢键组成时，相对于中性、等价氢键二聚体，混合价态的电子转移（ET）可稳定氢键相互作用每摩尔约 5 kcal。该项目的一个核心问题是氢键是否先于ET、随后发生或与ET同时发生。具体目标是：对 ET 如何通过氢键发生进行完整的物理描述；继续合成新的配合物，以更好地理解电子离域和氢键之间的相互作用； 并研究超分子结构的开启自组装，这些结构在还原时可以形成更强的氢键。 与二维红外光谱实验室 (2D IR) 的合作为超快基态分子中发生的 ET 和分子重排的动力学和机制提供了新的光谱见解。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值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

Direct observation of the intermediate in an ultrafast isomerization

直接观察超快异构化中的中间体

• DOI: 10.1039/c8sc03258k
• 发表时间: 2019
• 期刊: Chemical Science
• 影响因子: 8.4
• 作者: Porter, Tyler M.;Wang, Jiaxi;Li, Yingmin;Xiang, Bo;Salsman, Catherine;Miller, Joel S.;Xiong, Wei;Kubiak, Clifford P.
• 通讯作者: Kubiak, Clifford P.

Steric and electronic control of an ultrafast isomerization

超快异构化的空间和电子控制

• DOI: 10.1039/c9sc02359c
• 发表时间: 2019
• 期刊: Chemical Science
• 影响因子: 8.4
• 作者: Porter, Tyler M.;Ostericher, Andrew L.;Kubiak, Clifford P.
• 通讯作者: Kubiak, Clifford P.