"Electronic Relaxation Pathways in Nucleic Acid Derivatives Based on Functionalization of the Pyrimidine Chromophore"

在最基本的层面上，通过生命和光合作用的分子起源，光与物质的相互作用起着至关重要的作用。这些相互作用的许多应用继续通过医学、通信、技术和娱乐的进步给社会带来革命性的变化。控制物质与光相互作用的基本方式代表了许多对社会非常重要的现象的主要优先事项。尽管有许多化学家和物理学家的努力，这个巨大的挑战还没有完全被征服。化学系化学结构、动力学和机理b项目支持凯斯西储大学的Carlos E. Crespo-Hernández教授研究DNA成分嘧啶的战略性结构修饰是否可以用于合理控制能量耗散，以及对DNA光化学和光稳定性至关重要的过程。Crespo-Hernández教授和他的研究学生使用实验和理论相结合的方法来检验这个创新的想法。这项研究的变革潜力是分子设计原理的发展，用于控制生物和其他有机分子的光诱导途径。Crespo-Hernández教授旨在通过为高中生、本科生和研究生提供研究机会，并通过指导和作为榜样，激励学生进入并坚持科学研究和职业生涯。这些学生在现代光化学和光生物学、时间分辨技术和计算方法等重要领域进行交叉和多学科研究和培训的机会，以及参与国内和国际合作的机会，都提高了他们的兴趣。为来自大克利夫兰地区的经济弱势和代表性不足的学生提供研究机会。在这项研究中，Crespo-Hernández教授正在研究是否可以使用嘧啶发色团的选择性功能化来合理控制对核酸光化学至关重要的辐射和非辐射衰变途径。Crespo-Hernández教授和他的研究学生通过使用飞到微秒瞬态吸收光谱和多配置计算收集实验和理论数据来检验这一创新想法。目标包括：1)揭示合理选择的核酸衍生物的电子弛豫途径；2)绘制势能面拓扑；3)建立结构-动力学关系，揭示功能化如何调节辐射和非辐射衰变途径。与西班牙马德里大学Autónoma insamas Corral教授的理论小组密切合作，加强了对拟议的变革科学的影响和基本理解。了解嘧啶发色团的功能化如何调节核酸衍生物中的电子松弛途径可以帮助开发治疗药物、交联剂和荧光生物标志物，并且可能是理解遗传字母表为何仅由四个核碱基组成的关键。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

On the most fundamental level, through the molecular origins of life and photosynthesis, the interaction of light with matter has played an essential role. The many applications of these interactions continue to revolutionize society through advances in medicine, communications, technology, and entertainment. Controlling the fundamental way in which matter interacts with light represents a major priority for many phenomena of great importance for society. This grand challenge is yet to be fully conquered despite the efforts of many chemists and physicists. With this award, the Chemical Structure, Dynamics and Mechanisms-B Program of the Division of Chemistry is supporting Professor Carlos E. Crespo-Hernández of Case Western Reserve University to investigate whether strategic structural modification of the DNA component pyrimidine can be used to rationally control the dissipation of energy, processes critical to DNA photochemistry and photostability. Prof. Crespo-Hernández and his research students use a combination of experiment and theory to examine this innovative idea. The transformative potential of this research is the development of molecular design principles for the control of light-induced pathways in biological and other organic molecules in general. Prof. Crespo-Hernández seeks to motivate students to enter and persist in scientific studies and careers by providing research opportunities to high school, undergraduate and graduate students, and by mentoring and serving as a role model. The interests of these students are heightened by opportunities for cross- and multidisciplinary research and training in important areas of modern photochemistry and photobiology, time-resolved techniques, and computational methods, and by exposure to national and international collaborations. Research opportunities are provided for economically disadvantaged and underrepresented students from the Greater Cleveland area.In this research, Professor Crespo-Hernández is investigating whether selective functionalization of the pyrimidine chromophore can be used to rationally control the radiative and nonradiative decay pathways that are critical to nucleic acid photochemistry. Prof. Crespo-Hernández and his research students examine this innovative idea by gathering experimental and theoretical data using femto-to-microsecond transient absorption spectroscopy and multiconfigurational calculations. The objectives include: 1) unravel the electronic relaxation pathways in rationally selected nucleic acid derivatives; 2) map the topology of the potential energy surfaces; and 3) establish structure-dynamics relationships to reveal how functionalization regulates radiative and nonradiative decay pathways. Close collaboration with the theoretical group of Professor Inés Corral of the Universidad Autónoma de Madrid, Spain enhance the impact and increase fundamental understanding of the transformative science proposed. Understanding how functionalization of the pyrimidine chromophore regulates the electronic relaxation pathways in nucleic acid derivatives can assist in the development of therapeutic drugs, crosslinking agents, and fluorescent biomarkers, and may hold the key for understanding why the genetic alphabet is composed of only four nucleobases.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.