Collaborative Research: Electronic Coherence Effects in Multichromophore Systems Probed by Two-Dimensional Electronic Spectroscopy

在这个由化学系化学结构、动力学机制B和化学结构、动力学机制A项目共同资助的合作项目中，林X教授。&&美国西北大学化学系的陈教授和美国西北大学化学系的菲利克斯·N.来自北卡罗来纳州州立大学化学系的Castellano领导了一个项目，以了解相干电子运动对不同类别的多发色团合成平台中能量和电子转移的影响。 通过拟议的研究获得的知识将大大提高合理设计催化，光电子和能源可持续性的化学材料/设备的能力。 拟议的研究使大学研究生使用先进的激光光谱进行表征，将最先进的计算化学用于量子力学和分子动力学建模，并利用先进的化学实验室设施进行分子合成和结构表征，使他们获得发展多学科科学专业知识所需的广泛培训。 拟议的研究/教育活动与两所大学的众多K-12公共宣传活动相结合，包括北卡罗来纳州州立大学的光子学日和西北大学的NU Bond。 具体而言，他们将在研究中采用新开发的二维电子光谱学，具有约6飞秒的非常高的时间分辨率。合理设计的分子被设计成在其激发态下调节电子耦合，这是由光激发诱导的电子同相运动引起的电子相干性的原因或可以与之相关。所测量的相干性将与光诱导的分子内能量和/或电子转移化学的观察相关联，并使用不断发展的理论来合理化，以评估电子和/或电子振动相干性在这些与光活化相关的基本初级过程中的作用。两种类型的分子设计是针对这些调查：（1）铂（II）二聚体桥接的羟基吡啶具有金属-金属-配体电荷转移激发态，其中金属-金属键在光激发后瞬时形成;和（2）铂（II）二聚体，其末端环化配体装饰海湾取代的萘二酰亚胺基的能量和/或电子受体。 拟议的项目旨在收集激发态化学的新见解，以及如何利用这些知识来控制凝聚相，分子光子学和微电子学的反应性。该奖项反映了NSF的法定使命，并被认为值得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来支持。

In this collaborative project, co-funded by the Chemical Structure, Dynamics & Mechanisms B and the Chemical Structure, Dynamics & Mechanisms A programs of the Chemistry Division, Professor Lin X. Chen of the Department of Chemistry at Northwestern University and Professor Felix N. Castellano from the Department of Chemistry at North Carolina State University lead a project to understand the effects of coherent electronic motions in energy and electron transfer in distinct classes of multi-chromophoric synthetic platforms. The knowledge obtained through the proposed studies will greatly enhance the ability to rationally design chemical materials/devices for catalysis, optoelectronics, and energy sustainability. The proposed research engages University graduate students to use advanced laser spectroscopy for characterization, incorporates state-of-the-art computational chemistry for quantum mechanical and molecular dynamics modeling, and utilizes advanced chemistry laboratory facilities for molecular syntheses and structural characterization, engendering them with expansive training necessary for the development of multidisciplinary scientific expertise. The proposed research/education activities are integrated with numerous K-12 public outreach activities at both universities, including Photonics Day at North Carolina State University and NU Bond at Northwestern University. Specifically, they will employ newly developed two-dimensional electronic spectroscopy in their studies with very high time resolution of approximately 6 femtoseconds. The rationally designed molecules are engineered to tune electronic coupling in their excited states, which are either responsible for or can be correlated to electronic coherence originating from in-phase motions of electrons induced by photoexcitation. The measured coherences will be correlated with the observation of photoinduced intramolecular energy and/or electron transfer chemistry and rationalized using continuously developing theory to assess the role of electronic and/or vibronic coherence in these fundamental primary processes related to light activation. Two types of molecular designs are targeted for these investigations: (1) Pt(II) dimers bridged by hydroxypyridines featuring metal-metal-to-ligand charge transfer excited states where a metal-metal bond is transiently formed following light excitation; and (2) Pt(II) dimers whose terminal cyclometalating ligands are decorated with bay-substituted naphthalenediimide based energy and/or electron acceptors. The proposed project seeks to glean new insight into excited state chemistry and how this knowledge can be leveraged to control reactivity in condensed phases, molecular photonics, and photocatalysis.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.