Development of New Chemical Triggers for Spin-State Switching

在这个由化学系化学结构、动力学和机制B项目资助的项目中，科罗拉多州立大学的马修·肖尔斯教授正在研究新的过渡金属络合物，其物理(自旋)性质与客体分子的存在有关。这项研究旨在支持开发(1)廉价的比色传感器，以检测生物(磷酸盐、氯)和/或环境(硝酸盐、氰化物、高氯酸盐)的无色阴离子的重要性；以及(2)新型磁共振造影剂，在与目标分子相互作用时可逆地打开。该项目将支持非政府组织与其他7个研究小组之间的磁学合作，这些研究小组无法随时获得敏感的磁学测量技术和数据解释经验。潜在的社会利益包括发现新的阴离子传感器和开启的磁共振造影剂，以及为研究生和本科生提供跨学科培训基地。该项目专注于通过二次、非共价相互作用(如氢键)控制第一排过渡金属络合物的自旋态。其目的是通过各种化学触发，在两个方向上可靠地在低自旋态和高自旋态之间切换。这项研究包括新的Fe(II)、Fe(III)和Co(II)配合物的设计和合成，固态和溶液相结构和磁性的表征，以及通过UV-可见光和核磁共振光谱监测的客体结合研究。为了提高有希望的分子的环境稳定性，基于纤维素的杂化材料是目标，其中阴离子依赖的自旋态转换有望持续在表面-溶液界面。将依赖于阴离子的自旋态转换特性融入纸基设备中，为新的传感器创造了机会，这些传感器易于使用，具有广泛的便携性和易于(视觉)检测，适合广泛分发给公民以估计暴露于阴离子污染物。

In this project funded by the Chemical Structure, Dynamics and Mechanism B program of the Chemistry Division, Professor Matthew Shores of Colorado State University is investigating new transition metal complexes whose physical (spin) properties are linked to the presence of guest molecules. This research aims to support the development of (1) inexpensive colorimetric sensors for colorless anions of biological (phosphates, chloride) and/or environmental (nitrate, cyanide, perchlorate) significance; and (2) new magnetic resonance contrast agents that reversibly turn on when interacting with target molecules. The project will support magnetic collaborations between the PI and 7 other research groups who do not have ready access to sensitive magnetic measurement techniques and data interpretation experience. Potential societal benefits include the discovery of new anion sensors and turn-on magnetic resonance contrast agents as well as a cross disciplinary training ground for graduate and undergraduate students. The project focuses on controlling the spin-states of first-row transition metal complexes via secondary, non-covalent interactions such as hydrogen bonding. The aim is to switch reliably between low- and high-spin states, in both directions, with a variety of chemical triggers. The research involves design and synthesis of new Fe(II), Fe(III) and Co(II) complexes, solid state and solution phase structural and magnetic characterization, and guest binding studies monitored by UV-Visible and NMR spectroscopies. Toward increasing environmental stability of promising molecules, cellulose-based hybrid materials are targeted where anion-dependent spin-state switching is expected to persist at the surface-solution interface. Incorporating anion-dependent spin-state switching properties to paper-based devices generates an opportunity for new sensors, easy to use, with wide portability and easy (visual) detection, suitable for wide distribution to citizens to estimate exposure to anionic pollutants.