Responsive Boron Beta-Diketonate Materials

弗吉尼亚大学的卡桑德拉·L·弗雷泽教授得到化学系大分子、超分子和纳米化学计划的支持，研究基于二氟硼β-二酮酸盐的材料的发光(发光)性能，二氟硼β-二酮酸盐是一类有机响应性染料。这些染料在溶液、有组织介质和固体中对环境变化的许多不同反应方式正在被研究。这些敏感的染料材料在被刮伤、压碎或涂抹时会变色，并可以随着时间的推移自动擦除。因此，它们可以用作传感器、光学存储材料、安全油墨、智能环境、艺术品和其他产品的颜料。来自不同背景的学生在多学科环境中获得多方面的培训，与当地、国家和国际合作者网络接触，并学习科学传播技能。通过与当地一名高中理科教师建立联系，建立了与K-12学校的联系。一个跨学科的“真实世界化学实验室”正在开发中，目的是让学生、教师和社区参与与社会相关的化学和材料问题。这项提议的目的是探索二氟硼β-二酮和BDK染料在不同环境中的响应特性，并考虑如何利用这些特性进行应用。根据计算，这是通过制备材料集来实现的，这些材料集旨在调节溶液、纳米级脂质组件和分子固体中的发光性质。合成了具有给体-受体取代基、分子旋体、脂类等有机基团的染料。在溶液中测量了光学性质(发射、寿命、量子产额、超快光致发光衰减)，并与计算光谱和前线分子轨道进行了比较。探讨了溶致变色和粘致变色效应，与脂质体、膜和机械探针的研究有关。聚集诱导发射研究表征从溶液到固态的转变，而染料/聚合物共混物探测固态溶剂变色(介电、极性掺杂、染料-染料相互作用)、刚性变色效应(聚合物玻璃化转变温度、结晶度)和ML机制，并且易于加工以用于潜在用途。粉末和单晶X射线衍射仪提供了有关有序性、染料-染料相互作用和分子结构的信息，而原子力显微镜则显示了分子固体的结晶度和薄膜形态。染料组件是通过计算来建模的。利用差示扫描量热仪(DSC)对过冷液体进行了研究，并研究了染料在重纸和玻璃上的机械变色性能，以及具有良好性能的新基材。笔记本电脑/RGB相机成像系统将表征动态光学效应，如ML恢复、过冷液体结晶和薄膜和组件中的其他发光变化。这项研究的预期结果是对硼和二酮染料在溶液、有组织的脂类介质和固体中的性质有更深的基础了解。这将导致更合理地设计用于成像、传感和检测应用的刺激响应、发光的硼和二酮材料。

Professor Cassandra L. Fraser of the University of Virginia is supported by the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry to investigate the luminescent (light emitting) properties of materials based on difluoroboron beta-diketonates, a family of organic responsive dyes. The many different ways by which these dyes respond to changes in their environment in solution, organized media and the solid state are being investigated. These responsive dye materials change color when scratched, crushed or smeared, and can self-erase with time. As such, they can find use as sensors, optical memory materials, security inks, intelligence contexts, pigments for art and other products. Students from diverse backgrounds obtain multifaceted training in a multidisciplinary environment, engage with a network of local, national and international collaborators and learn science communication skills. Outreach towards K-12 schools is established through ties to a local high school science teacher. An interdisciplinary "Real World Chemistry Lab" is under development to engage students, faculty and the community in chemistry and materials related issues relevant to society.The objective of this proposal is to explore responsive properties of difluoroboron beta-diketonate and bdk dyes in different environments and to consider ways to harness these properties for applications. Informed by computation, this is accomplished by preparing material sets designed to modulate luminescence properties in solution, nanoscale lipid assemblies and molecular solids. Dyes with donor-acceptor substituents, molecular rotors, lipids and other organizing groups are synthesized. Optical properties (emission, lifetime, quantum yield, ultrafast photoluminescence decay) are measured in solution and compared to computed spectra and frontier molecular orbitals. Solvatochromic and viscochromic effects are probed, relevant to investigations with liposomes, membranes and mechanistic probe development. Aggregation induced emission studies characterize the transition from solution to the solid state, whereas dye/polymer blends probe solid-state solvatochromism (dielectric, polar dopants, dye-dye interactions), rigidochromic effects (polymer glass transition temperature, crystallinity), and ML mechanisms, and are readily processable for potential uses. Powder and single crystal XRD provide information about order, dye-dye interactions, and molecular structure, whereas AFM reveals crystallinity and thin film morphologies in molecular solids. Dye assemblies are modeled computationally. Super cooled liquids are investigated by DSC, and mechanochromic properties of dyes are studied for thin films on weigh paper and glass along with new substrates with promising behaviors. A laptop/RGB camera imaging system will characterize dynamic optical effects such as ML recovery, supercooled liquid crystallization, and other luminescence changes in films and assemblies. The expected outcomes of this research are greater fundamental understanding of boron and diketone dye properties in solution, organized lipid media and the solid state. This will lead to more rational design of stimuli responsive, luminescent boron and diketone materials for imaging, sensing and detection applications.