CAS: Collaborative Research: Mapping Excited State Trajectories of Multi-metal Centered Complexes by Two-Dimensional Electronic Spectroscopy

CAS：合作研究：通过二维电子光谱绘制多金属中心配合物的激发态轨迹

• 批准号: 2247821
• 负责人: Lin Chen
• 金额: $ 30万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2247821&HistoricalAwards=false
• 关键词: CAS; Collaborative; Research; Mapping; Excited

With support of the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Lin X. Chen of the Department of Chemistry at Northwestern University and Professor Felix N. Castellano of the Department of Chemistry at North Carolina State University seek to understand the effects of vibronic coherence in excited state photochemical and photophysical processes for energy and electron transfer reactions. This project aims to gain new insights into light-matter interactions at the levels of electrons and atoms and use this knowledge to leverage controlled reactivity in condensed phases, molecular photonics, and photocatalysis via both chemical structural tuning and light modulation. The knowledge obtained through the proposed studies has the potential to significantly enhance our ability to rationally design chemical materials/devices for catalysis, optoelectronics, and energy sustainability. The proposed research engages University graduate students in advanced laser spectroscopy for characterization, incorporates state-of-the-art computational chemistry, and utilizes advanced chemistry laboratory facilities for molecular syntheses and structural characterization, engendering multidisciplinary scientific expertise. The proposed research and education activities are integrated with K-12 public outreach events at both institutions. The collaborative team will investigate the effects of vibronic coherence in excited state electron transfer in three classes of multi-chromophore synthetic platforms using two-dimensional electronic spectroscopy (2DES) and broadband transient absorption (BBTA) spectroscopy. The three specific molecular platforms are (1) new generation Pt(II) co-facial dimers featuring terminal tridentate cyclometalating ligands bridged by a single substituted pyrazolate, hydroxypyridine, mercaptopyridine, or diphosphine featuring metal-metal-to-ligand charge transfer (MMLCT) excited states where a metal-metal bond is transiently formed following light excitation; (2) Pt(II) dimers from (1) whose terminal cyclometalating ligands are decorated with naphthalenediimide (NDI)-based electron acceptors; and (3) co-facial self-assembled polynuclear aggregates formed from Pt(II) monomer building blocks with and without electron acceptors. These experimental systems are engineered to tune electronic coupling in their excited states, which are either responsible for or can be correlated to electronic and vibronic coherence originating from in-phase nuclear motions induced by photon excitation. The detection of electronic and vibronic coherences in these designed molecules will be assessed using broadband 2DES featuring ~7 femtosecond time resolution and sufficiently broad spectral bandwidth. The measured coherences will be correlated with photophysical processes and photoinduced intramolecular electron transfer chemistry, rationalized using continuously developing theory to assess the role of electronic and/or vibronic coherence in these fundamental primary processes related to light activation.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.

在化学结构，动力学和机制B计划的支持下，西北大学化学系教授和北卡罗来纳州立大学化学系的Felix N. Castellano教授试图了解振动coherence的效果激发兴奋的国家光化学和摄影过程中的效果。该项目旨在在电子和原子水平上获得对光 - 物质相互作用的新见解，并利用这些知识来利用通过化学结构调节和光调制来利用冷凝相，分子光子学和光催化的控制反应性。通过拟议的研究获得的知识有可能显着增强我们合理地设计化学材料/设备进行催化，光电子和能量可持续性的能力。拟议的研究使大学研究生进行了高级激光光谱，以进行表征，结合了最先进的计算化学，并利用了高级化学实验室设施来进行分子合成和结构表征，从而创造了多学科科学专业知识。拟议的研究和教育活动与两个机构的K-12公共外展活动融合在一起。 该协作团队将使用二维电子光谱（2DES）和宽带瞬态吸收（BBTA）光谱学在三类多肉眼合成平台中研究激发状态电子转移中振动相干性的影响。 The three specific molecular platforms are (1) new generation Pt(II) co-facial dimers featuring terminal tridentate cyclometalating ligands bridged by a single substituted pyrazolate, hydroxypyridine, mercaptopyridine, or diphosphine featuring metal-metal-to-ligand charge transfer (MMLCT) excited states where a metal-metal bond is transiently formed following light excitation; （2）pt（ii）（1）的二聚体，其末端环数配体用萘二酰亚胺（NDI）基于基于电子的电子受体； （3）由有或没有电子受体的PT（II）单体构建块形成的共生自组装多核聚集体。这些实验系统经过精心设计，以调整其激发态的电子耦合，这些态是由光子激发引起的相期核运动的负责或可以与电子和振动相干性相关的。这些设计分子中电子和振动相干的检测将使用宽带2DE进行评估，这些宽带2DE具有〜7飞秒时间分辨率和足够宽的光谱带宽。测得的相干将与光物理过程和光诱导的分子内电子转移化学相关，并使用连续发展的理论合理地对这些与光激活相关的基本主要过程中电子和/或振动相干性的作用进行合理化，以反映NSF的法定任务，反映了经过评估的授权，这一奖项已被赋予构成且受到支持。