CAS: Ultrafast Spectroscopy and Photoisomerization of Iron Sulfoxide Complexes

新墨西哥大学的Jeffrey Rack教授在化学部化学结构、动力学和机理B(CSDM-B)计划(CSDM-B)和既定的刺激竞争研究计划(EPSCoR)的支持下，正在开发具有有趣的光谱和磁光性质的新类别的铁配合物。本研究的目的是设计一种新型的具有光活性的亚砜铁络合物。该项目位于有机化学、无机化学和物理化学的交界处，适合于各种经验层次的科学家的教育。新墨西哥大学是少数族裔占多数的机构，Rack研究小组致力于为科学方面代表性不足的学生提供最高水平的教育和培训，并将在该奖项下继续这样做。培训高中和中学化学教师的外联活动是研究项目的一部分。这项拟议的工作详细说明了一项研究计划，该计划旨在创建具有光活性的铁多吡啶亚砜络合物。这项工作的目的是发现光引发的亚砜异构化是否可以以类似于相关Ru络合物的方式被支撑在铁中心上。在Ru络合物中，3MLCT激发激发瞬间生成Ru~(3+)，导致亚砜从S键到O-键的激发态异构化。Rack教授和他的研究团队的目标是在铁上重现这种光化学，目的是通过O-键配位模式稳定高自旋态或中自旋态。要观察铁上的这种化学作用，必须克服两个主要挑战：铁上的3MCLT(金属-配体电荷转移)状态由于原生效应而很少出现，以及亚砜在铁上的异构化作用尚未见报道。初步结果证明，这些挑战是可以克服的，并且可以实现在铁上实现S-O-亚砜键合的目标。如果成功，能够实现这样的中高自旋态亚硫氧化物络合物将是该领域的重大进步，因为这将把这种化学带入地球丰富的过渡金属空间领域，并为有机金属化学家开辟一条重要的新探索途径。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Structure, Dynamics & Mechanisms-B (CSDM-B) Program of the Chemistry Division (CHE), and the Established Program to Stimulate Competitive Research (EPSCoR), Professor Jeffrey Rack of the University of New Mexico is developing new classes of iron complexes with interesting spectroscopic and magneto-optical properties. The goal of this research is to design new photoactive iron complexes with sulfoxide ligands. The project lies at the interface of organic, inorganic, and physical chemistry, and is appropriate for education of scientists at all levels of experience. The University of New Mexico is a majority minority institution and the Rack research group is works to provide the highest level of education and training for students underrepresented in science and will continue to do so under this award. Outreach activities involving the training of high school and middle chemistry teachers is part of the research project. The proposed work details a research plan to create photoactive iron polypyridine sulfoxide complexes. The goal of this work is to discover if phototriggered sulfoxide isomerization can be supported on iron centers in a fashion similar to that on related ruthenium complexes. In ruthenium complexes, 3MLCT excitation prompts transient Ru3+ formation, which induces excited state isomerization of the sulfoxide from S-bonded to O-bonded. Professor Rack and his research team aim to reproduce this photochemistry on iron with the objective of stabilizing high or intermediate spin states with the O-bonded coordination mode. There are two major challenges that must be met to observe this chemistry on iron: 3MCLT (metal-to-ligand charge-transfer) states on iron are rare due to the primogenic effect and sulfoxide isomerization on iron has not been reported. Preliminary results provide evidence that these challenges can be overcome and that the goal of achieving S- to O-sulfoxide bonding on iron can be achieved. If successful, the ability to achieve such intermediate to high spin state Fe-sulfoxide complexes would be a significant advance for the field as this would bring this chemistry into the realm of earth abundant transition metal space, and open up an important new avenue of exploration for organometallic chemists.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.