Highly Luminescent Multinuclear Coinage Metal Arrays with a Twist: A New Approach to Design Light-Emitting Molecular Strings and Coils

在化学部化学合成计划的支持下，肯尼索州立大学化学与生物化学系的Michael Stollenz将探索含有铜、银和金元素的单个金属原子的新型分子，这些金属原子以线性方式排列，彼此非常接近。这些配合物是高度发光的，并且发光性质可以通过这些配合物的结构来控制。这样的分子串也有潜力作为导电分子线和线圈，用于在亚微观尺度上的小型化电子器件中的应用。具有多个铜、银和金离子的发光络合物在这方面特别令人感兴趣，因为它们可以应用于分子/有机发光二极管（OLED）。为了构建这种性质的分子串，需要定制的合成方法来靶向和控制单个金属离子的线性排列。Stollenz和他的团队将致力于开发一种新的方法，不仅可以生产严格的铜，银和金离子的线性阵列，而且可以生产基本弯曲的排列，因此代表分子线圈。主要目的是研究结构变化如何影响这些化合物的发射特性。这种分子线圈的一个长期前景是，如果将其嵌入电子电路中，可以将其作为微小的电磁铁，集成到纳米机器和其他纳米级电子设备中。这样的设备可以反过来应用于在人体内输送药物的纳米机器人。如果这些装置是发光的，则它们的路径可以通过荧光成像来跟踪。这项工作的更广泛影响将包括指导和培训来自肯尼索州立大学大量服务不足群体的本科生和硕士生。该研究计划的重点是开发和实施新的策略，以多核钴金属阵列作为分子串和线圈，作为分子/有机发光二极管（OLED）的关键组件。基本的合成方法的目的是提供一个基本的方法来控制线性簇组装体的聚集，并提供一个洞察一般的多核络合物阵列的配位化学。具体地，靶向能够容纳以线性方式排列的至少四个铜中心的新的双（脒）配体的库。Cu（I）离子的掺入将通过采用清洁的有机金属Cu（I）源（均三甲苯基铜）来完成。具有额外的末端N-供体基团的双（脒）配体将被MR（M = Cu、Ag、Au; R = Cl、Mes）络合物片段选择性地保护。这些迄今未知的双核金属配体将被用作新的线性或成束的同质Cu（I）或异质Cu（I）/Ag（I）或Cu（I）/Au（I）簇合物的结构单元，具有作为发光材料的前景。最后，该计划将为本科生/研究生研究生和博士后提供合成，表征技术（晶体学和光谱学），口头陈述技能，科学写作，实验室安全和数据管理方面的深入培训。这些活动将使研究生和博士后研究人员做好准备，以实现他们在科学或工业领域雄心勃勃的职业目标。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support of the Chemical Synthesis Program in the Division of Chemistry, Michael Stollenz of the Department of Chemistry and Biochemistry at Kennesaw State University will explore novel molecules containing individual metal atoms of the elements copper, silver, and gold that are arranged in a linear fashion and are in close proximity to each other. These complexes are highly luminescent and the luminescence properties can be controlled by the structures of these complexes. Such molecular strings also have the potential to serve as conducting molecular wires and coils for applications in miniaturized electronic devices on the submicroscopic scale. Luminescent complexes with multiple copper, silver, and gold ions are of particular interest in this regard, since they can be applied in molecular/organic light-emitting diodes (OLEDs). For the construction of molecular strings of this nature, tailored synthetic methodologies are required to target and control linear arrangements of the individual metal ions. Stollenz and his group will work to develop a new methodology for producing not only strictly linear arrays of copper, silver, and gold ions, but also arrangements that are substantially bent and therefore represent molecular coils. The major goal is to investigate how the structural changes affect the emission properties of these compounds. A long-term prospect for such molecular coils, if embedded in electronic circuits, is to utilize them as tiny electromagnets that can be integrated in nanomachines and other nanoscaled electronic devices. Such devices can in turn be applied in nanorobots that deliver drugs inside a human body. If these devices are luminescent, their path can be followed by fluorescence imaging. The broader impacts of this work will include the mentoring and training of undergraduate and masters students from the significant population of underserved groups at Kennesaw State University. This research program focuses on the development and implementation of new strategies to multinuclear coinage metal arrays as molecular strings and coils that serve as key components in molecular/organic light-emitting diodes (OLEDs). The underlying synthetic methods aim to provide a fundamental approach to control aggregation of linear cluster assemblies and to provide a insight into the coordination chemistry of multinuclear complex arrays in general. Specifically, a library of new bis(amidine) ligands that are capable of accommodating at least four copper centers, arranged in a linear fashion, are being targeted. The incorporation of Cu(I) ions will be accomplished by employing a clean organometallic Cu(I) source, mesitylcopper. Bis(amidine) ligands with additional terminal N-donor groups will be selectively protected by MR (M = Cu, Ag, Au; R = Cl, Mes) complex fragments. These hitherto unknown dinuclear metalloligands will be utilized as building blocks for new linear or bundled homonuclear Cu(I) or heterobimetallic Cu(I)/Ag(I) or Cu(I)/Au(I) cluster assemblies with promise as luminescent materials. Finally, this program will provide in-depth training of undergraduate/graduate research students and postdocs in synthesis, characterization techniques (crystallography and spectroscopy), oral presentation skills, scientific writing, laboratory safety, and data management. These activities will prepare research students and postdoctoral researchers to achieve their ambitious career goals in science or industry.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.