Control of Excited State Dynamics of Ru(II) Complexes for Dual Activity

在这个由化学部化学结构、动力学机制B项目资助的项目中，俄亥俄州州立大学化学和生物化学系的Claudia Turro与德克萨斯农工大学的Kim Dunbar和韦恩州立大学的Jeremy Kodanko合作，旨在了解过渡金属络合物在非常早期吸收光子后发生的步骤--在飞秒到皮秒的范围内。这些金属配合物的应用包括太阳能转换和光动力治疗药物的输送。该项目还将专注于设计新的复合物，通过低能量可见光到近红外光的照射，释放更广泛的配体，特别是那些强烈配位的配体。一个主要的目标是研究表现出双重反应性的复合物。关于光诱导配体交换获得的基本知识将有助于设计需要消除配体交换过程的络合物，以增加三重态金属-配体电荷转移（3 MLCT）状态的寿命，这是太阳能转换中的一个重要因素。这个合作团队也有能力为科学领域代表性不足的学生提供最高水平的教育和培训。本项目的主要目标是了解早期Ru（II）配合物中的电子物理过程的基本原理。 重点是控制有效的光取代的因素，以及双活性化合物。 这些物质产生细胞毒性单线态氧，并进行配体交换。 在这些复合物中填充两种不同的光活性状态的机制仍然未知，并且与为有机分子开发的光化学规则相反。此外，光诱导的药物释放使用钌（II）配合物是高度依赖于身份的离开和辅助配体，一个点，将被调查。据推测，金属为中心的三重态配体场（3LF）状态的快速布居是发生配体交换所必需的，但目前尚不清楚配体交换是否也直接发生在最低能量的3 MLCT（三重态金属-配体电荷转移）状态。关于光诱导配体交换获得的基本知识将有助于设计或需要消除配体交换过程的络合物，以增加3 MLCT状态的寿命，这是太阳能转换中的一个重要因素。拟议的研究包括电子和振动超快光谱研究，以及合成新的复合物，以改善配体解离和双重作用。该奖项反映了NSF的法定使命，并已被认为是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的支持。

In this project, funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Claudia Turro of the Department of Chemistry and Biochemistry at Ohio State University, in collaboration with Kim Dunbar at Texas A&M University and Jeremy Kodanko at Wayne State University, aims at understanding the steps that take place after a transition metal complex absorbs a photon of light at very early times--in the femtosecond to picosecond domain. Applications of these metal complexes include solar energy conversion and the delivery of drugs for photodynamic therapy. The project will also focus on the design of new complexes that release a wider range of ligands, especially those that coordinate strongly, through irradiation with low energy visible to near-infrared light. One major goal is the investigation of complexes that exhibit dual-reactivity. The basic knowledge gained regarding photoinduced ligand exchange will aid in the design of complexes that require the ligand exchange process to be eliminated in order to increase the lifetime of the triplet metal-to-ligand charge transfer (3MLCT) state, a factor important in solar energy conversion. This collaborative team is also well positioned to provide the highest level of education and training for students underrepresented in science. The major goal of this project is to understand the basic principles governing photophysical processes in Ru(II) complexes at early times. Focus is on the factors that control efficient photosubstitution, as well as dual-activity compounds. These substances generate cytotoxic singlet oxygen and also undergo ligand exchange. The mechanism by which two different photoactive states are populated in these complexes remains unknown and is counter to the rules of photochemistry developed for organic molecules. In addition, photoinduced drug release using Ru(II) complexes is highly dependent on the identity of both the leaving and ancillary ligands, a point that will be investigated. It is hypothesized that fast population of the metal-centered triplet ligand field (3LF) state is required for ligand exchange to take place, but it is yet unknown if ligand exchange also occurs directly from the lowest-energy 3MLCT (triplet metal-to-ligand charge transfer) state. The basic knowledge gained regarding photoinduced ligand exchange will aid in the design or complexes that require the ligand exchange process to be eliminated in order to increase the lifetime of the 3MLCT state, a factor important in solar energy conversion. The proposed research includes electronic and vibrational ultrafast spectroscopic studies, as well as the synthesis of new complexes for improved ligand dissociation and for dual action.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.