Engineering cyanine aggregation and self-assembly to access exceptionally red-shifted organic chromophores

在这个由化学系大分子、超分子和纳米化学项目资助的项目中，加州大学洛杉矶分校化学系的Ellen M. Sletten教授和Justin R. Caram教授正在开发新的荧光化合物，这种化合物可以在电磁波谱的红外区域重新发射光。红外线通常是人眼看不见的，但可以感觉到或探测到热量。与x射线类似，这种光可以穿透许多物体，包括皮肤和组织。本研究中使用的化合物非常复杂，但很容易制成具有独特性质的化合物，使它们具有高度的颜色。此外，当通过溶液中的分子相互作用组装时，它们的亮度要高几个数量级。光强对于生物医学成像应用，如早期检测人体癌细胞尤为重要。此外，这项研究与开发新的和令人兴奋的设备在电信相关的光学领域，其中信息是通过远距离通信使用红外光。这项工作为本科生和研究生在合成有机化学和分析表征技术方面提供培训和教育。还开展了若干外联活动，其中包括向更广泛的社区宣传荧光和电磁辐射。这项研究是让代表性不足的少数族裔和社区大学生参与科学研究的绝佳途径。本研究的重点是在电磁波谱的短波红外区域（SWIR, 1000 ~ 2000 nm）发射的菁荧光团j聚集体。为了创建SWIR j聚集体，系统地研究了促进发色团自组装成j聚集体的因素。花青素染料是理想的配合物，因为它们很容易合成，并且已知形成具有显著红移的j聚集体。在项目的第一部分，通过系统的化学修饰和环境控制，探索了四种假设控制j聚集的现象（两亲性、反离子、聚甲基链修饰和杂环极化性）。在第二个目标中，这些策略被扩展到已知的SWIR菁染料。这项研究有可能产生用于生物成像和电信的变革性新型纳米材料。该奖项反映了美国国家科学基金会的法定使命，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。

In this project funded by the Macromolecular, Supramolecular, and Nanochemistry Program in the Division of Chemistry, Professors Ellen M. Sletten and Justin R. Caram of the Department of Chemistry at the University of California-Los Angeles are developing new fluorescent chemical compounds that re-emit light in the infrared region of the electromagnetic spectrum. Infrared waves are generally invisible to the human eye, but can be felt or detected as heat. Similar to x-rays, this light can penetrate through many objects, including skin and tissue. The compounds used in this research are very complex, yet easily made with unique properties that enable them to be highly colored. Additionally, they are several orders of magnitude brighter when assembled through molecular interactions in solution. The light intensity is particularly important for biomedical imaging applications such as early detection of cancer cells in human body. Additionally, the research is of relevance to the development of new and exciting devices in telecom-relevant optical fields in which information is communicated through long distances using infrared light. This work provides training and education to undergraduate and graduate students in synthetic organic chemistry and analytical characterization techniques. Several outreach activities are also developed that include educating the broader community about fluorescence and electromagnetic radiation. The research is an excellent avenue for engaging underrepresented minority and community college students in science.This research is focused on J-aggregates of cyanine fluorophores which emit in the shortwave infrared region of the electromagnetic spectrum (SWIR, 1000 to 2000 nm). To create SWIR J-aggregates, a systematic study of the factors that promote the self-assembly of chromophores into J-aggregates is conducted. Cyanine dyes are ideal complexes because they are easily synthetically accessible and are known to form J-aggregates with significant redshifts. In the first part of the project, four phenomena that are hypothesized to control J-aggregation (amphiphilicity, counterions, polymethine chain modification, and heterocycle polarizability) are explored through systematic chemical modifications and environmental control. In the second aim, these strategies are extended to a known SWIR cyanine dye. This research has the potential to generate transformative novel nanomaterials for applications in bioimaging and telecommunications.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.