Toward High Intensity Forbidden EPR Transitions In Bimetallic Complexes

双金属配合物中高强度禁止的 EPR 转变

• 批准号: 2419767
• 负责人: Joseph Zadrozny
• 金额: $ 45万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-02-15 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2419767&HistoricalAwards=false
• 关键词: Toward; Intensity; Forbidden; EPR; Transitions

With support from the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Joseph Zadrozny of the Department of Chemistry at Colorado State University is developing new classes of dinuclear transition metal complexes to probe forbidden electron paramagnetic resonance (EPR) spectroscopic transitions. The goal of this research is to exploit the characteristics of these dinuclear species to understand how molecular structure can assist in violating EPR selection rules to enable high intensity transitions. The specific transitions being explored may yield new capabilities for bioimaging techniques that use EPR transitions. The research project spans the interface of inorganic and physical chemistries with synthetic and spectroscopic analyses as a key part of the work. The broader outreach goals for the program will be to create an easy-to-access lesson for synthetic chemists to approach the selection rules of EPR. This plan will follow the pedagogical strategies commonly employed for more common techniques, e.g. UV-vis spectroscopy, and as such aims to be a cornerstone in bringing new chemists into the EPR arena.The longer-term goal for the work is to enable low-frequency EPR transitions at high magnetic field, which would permit the chemical sensitivity of EPR imaging to be integrated with MRI. The singlet-to-triplet transition of two-spin systems is a promising way to realize such an EPR transition, because of its unique field dependence. Yet, the transition is forbidden and therefore weak hence, chemical design strategies for molecules to override the EPR selection rule and increase signal intensity are needed. Dinuclear metal complexes have a plethora of magnetic interactions that could potentially violate the EPR selection rule, but experimental tests of the efficacy of these violations have yet to be performed. This work will study the singlet-to-triplet transition in a variety of dinuclear metal complexes to explore how exchange coupling, hyperfine coupling, and relative spin orientation all contribute to the intensity of the forbidden resonance.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B计划的支持下，科罗拉多州立大学化学系的Joseph Zadrozny教授正在开发新的杂型跃迁金属复合物，以探测禁止的电子顺磁性复位（EPR）光谱过渡。 这项研究的目的是利用这些杂种物种的特征，以了解分子结构如何有助于违反EPR选择规则以实现高强度过渡。探索的特定过渡可能会为使用EPR转换的生物成像技术提供新的功能。该研究项目跨越了无机和物理化学的界面，并通过合成和光谱分析作为工作的关键部分。该计划的更广泛的外展目标是为合成化学家创建一个易于获取的课程，以了解EPR的选择规则。该计划将遵循通常用于更常见技术的教学策略，例如UV-VIS光谱法，因此旨在成为将新化学家带入EPR领域的基石。该工作的长期目标是使高磁场的低频EPR转变能够使EPR成像的化学敏感性与MRI集成。由于其独特的场依赖性，两旋链系统的单线到三旋转系统是实现这种EPR过渡的一种有希望的方法。然而，禁止过渡，因此弱，因此需要分子的化学设计策略来覆盖EPR选择规则并增加信号强度。双核金属复合物具有大量的磁相互作用，可能会违反EPR选择规则，但是尚未执行这些违规功效的实验测试。这项工作将研究各种杂型金属复合物的单线到三重奏过渡，以探索交换耦合，超精细耦合和相对旋转方向如何有助于禁止共鸣的强度。本奖项奖反映了NSF的法定任务，并通过使用基金会的智力效果和广泛的cr and crotial和广泛的评估来表现出值得的支持。