Photophysical properties of molecules: From biological imaging to new materials

分子的光物理特性：从生物成像到新材料

• 批准号: RGPIN-2020-04347
• 负责人: Brown, Alexander
• 金额: $ 3.5万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=747801
• 关键词: Photophysical; properties; molecules; biological; imaging

Computational study allows the interpretation of modern experimental measurements. Importantly, models can be developed to generalize observed behaviour, understand related systems, and design improved molecules or materials. Our research develops and uses theoretical and computational methods for understanding and predicting molecular structure and properties. The over-arching emphasis is on excited electronic states, which are connected to experimental observables (e.g., 1- or multi-photon absorption, light emission, photochemistry...). However, the problems and applications studied are diverse: (1) In biological imaging, the focus is on both fluorescent proteins and fluorescent nucleobase analogues, which mimic the structure and function of the natural nucleobase building blocks of DNA and RNA. Fluorescent proteins are useful probes of biological mechanisms, functions, and structures in molecular and cell biology. Meanwhile, fluorescent nucleobase analogues are needed because their natural counterparts are non-fluorescent, and thus cannot be used to observe DNA and RNA structure, function, and dynamics directly. For both classes of probes, there is rapidly developing research moving beyond one-photon absorption to two- or three-photon absorption, as the longer wavelengths used permit deeper penetration and allow better focus, which are critical needs for live cell or organism imaging. However, corresponding computational study is lagging behind experimental development. The proposed research aims to fill that gap. Overall, a diversity of multi-photon processes in biological probes will be examined with the goals of a better understanding of the underlying photophysics, rationalizing the connections between structure and photophysical properties, and assisting with the design of new improved probes specifically for multi-photon applications. (2) A number of new phosphorescent compounds containing tellurium and bismuth, rather than expensive transition metals, have recently been synthesized and characterized. Phosphorescence is the basis for many technologies, including light-emitting devices (LEDs). While a basic understanding of the photophysics has been obtained computationally, including qualitative ideas on why compounds are phosphorescent versus non-phosphorescent, a detailed understanding requires the use of more sophisticated quantum chemistry approaches than have been used to-date. Moreover, to understand the relative quantum yields, new tools will be developed and used to map the relaxation pathways following photoexcitation, which will lead to an improved understanding of the factors leading to higher (or lower) quantum yields, i.e., better or worse materials. Through these simulations of the properties of known compounds, we can rationally design new materials with improved spectral characteristics. (3) We will develop and apply methods for studying quantum dynamics in small molecules for atmospheric chemistry and astrochemistry.

计算研究可以解释现代实验测量。重要的是，可以开发模型来概括观察到的行为、理解相关系统并设计改进的分子或材料。我们的研究开发并使用理论和计算方法来理解和预测分子结构和性质。首要重点是激发电子态，它与实验可观察到的现象（例如，单光子或多光子吸收、光发射、光化学......）有关。然而，研究的问题和应用是多种多样的：（1）在生物成像中，重点是荧光蛋白和荧光核碱基类似物，它们模仿DNA和RNA的天然核碱基构建块的结构和功能。荧光蛋白是分子和细胞生物学中生物机制、功能和结构的有用探针。同时，需要荧光核碱基类似物，因为它们的天然对应物是非荧光的，因此不能用于直接观察DNA和RNA的结构、功能和动力学。对于这两类探针，研究正在迅速发展，从单光子吸收转向双光子或三光子吸收，因为使用的较长波长允许更深的穿透并允许更好的聚焦，这是活细胞或生物体成像的关键需求。然而，相应的计算研究落后于实验发展。拟议的研究旨在填补这一空白。总体而言，将检查生物探针中的多种多光子过程，目的是更好地理解基础光物理学，合理化结构和光物理性质之间的联系，并协助设计专门针对多光子应用的新改进探针。 (2) 最近合成并表征了许多含有碲和铋而不是昂贵的过渡金属的新型磷光化合物。磷光是许多技术的基础，包括发光器件 (LED)。虽然通过计算获得了对光物理学的基本了解，包括关于为什么化合物是磷光与非磷光的定性想法，但详细的理解需要使用比迄今为止使用的更复杂的量子化学方法。此外，为了了解相对量子产率，将开发并使用新工具来绘制光激发后的弛豫路径，这将有助于更好地理解导致更高（或更低）量子产率的因素，即更好或更差的材料。通过对已知化合物特性的这些模拟，我们可以合理地设计具有改进光谱特性的新材料。 （3）我们将开发和应用研究大气化学和天体化学小分子量子动力学的方法。