Collaborative Research: Design and Study of Chalcogen-Containing Cationic Dyes for Photocatalysis

开发将分子转化为有用的材料和产品的方法是化学家面临的一个关键挑战。一种常见的转化是氧化反应，即在分子中添加氧气或从分子中去除电子。氧化反应往往依赖有毒的试剂，产生大量的废物。分子氧的使用可以减少这些反应的成本和产生的废物量。空气中也含有丰富的分子氧。科学家通常不知道如何利用大气中的氧气将分子转化为所需的产品。在这个项目中，波特兰州立大学的麦考密克博士以及布法罗大学的德蒂和库克博士正在研究一种染料，这种染料可以利用光能与大气中的氧气进行理想的分子转化。通过了解改变染料的结构如何影响其反应性，就有可能控制和靶向这些氧化反应。McCormick博士、Detty博士和Cook博士致力于通过实施新课程来增加可持续发展领域的教育。他们为学生提供研究实习机会，以提高他们对发展对环境的影响的认识，以及他们作为科学家在创造可持续解决方案方面的作用。课程修订可能会增加学生对可持续发展和光化学问题的参与度。这些单元的传播是为了让全国各地的学校采用该课程，该课程侧重于绿色化学、环境保护和可再生能源的原则。一个更有参与度和更有见识的科学工作者也许能够更好地解决当前和未来的可持续发展问题。McCormick、Detty和Cook得到了化学部化学催化计划的支持，该计划旨在研究含硫染料作为光催化氧化还原反应的光敏剂。由于其在实验室和工业规模绿色生产小分子的潜力，光诱导氧化还原催化用于合成转化引起了人们的兴趣。通过在染料的黄色或吡喃核中交换硫族原子(O、S或Se到Te)，可以控制染料中的氧化还原行为，以及吸收波长、荧光产量和寿命，以及三线态产量和寿命。含硫的染料起到光氧化剂的作用，因为激发态可以接受一个电子，从而使底物发生单电子氧化。激发态还可以跨系统从单态到三态，然后与基态氧相互作用生成单态氧，单态氧可以作为一种有效的氧化剂。这项研究通过提供一条产生过氧化氢的途径，减少碳排放，可能会减少对化石燃料的依赖。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The development of methods to transform molecules into useful materials and products is a key challenge facing chemists. One common transformation is an oxidation reaction, where oxygen is added to or electrons are removed from a molecule. Oxidation reactions often rely on toxic reagents that produce a large amount of waste. The use of molecular oxygen could reduce both the cost of these reactions and the amount of waste produced. Molecular oxygen is also abundant in air. Scientists generally do not know how to use atmospheric oxygen to transform molecules into desired products. In this project, Dr. McCormick of Portland State University and Drs. Detty and Cook of the University at Buffalo are investigating dyes that can use energy from light to make desirable molecular transformations with atmospheric oxygen. By understanding how changing the structure of a dye influences its reactivity, it may be possible to control and target these oxidation reactions. Drs. McCormick, Detty, and Cook are dedicated to increasing education in areas of sustainability via the implementation of new courses. They provide research internships to students to increase their awareness of the impact of development on the environment and their role as scientists in creating sustainable solutions. The curriculum revisions may increase student engagement in issues of sustainability and photochemistry. The modules are disseminated to allow schools across the country to adopt the curriculum, which focuses on on principles of green chemistry, environmental protection, and renewable energy. A more engaged and informed science workforce may be better able to solve current and future problems of sustainability.Drs. McCormick, Detty, and Cook are supported by the Chemical Catalysis Program of the Chemistry Division to investigate chalcogen-containing dyes as photosensitizers for photocatalytic redox reactions. The use of photo-induced redox catalysis for synthetic transformations is of interest due to its potential for the green production of small molecules at both laboratory and industrial scale. The interchange of the chalcogen atoms (O, S, or Se to Te) in the xanthylium or pyrylium core of the dyes allows control of redox behavior in the dyes, as well as wavelengths of absorption, fluorescence yields and lifetimes, and triplet yields and lifetimes. The chalcogen-containing dyes function as photo-oxidants in that the excited state can accept an electron to give a one-electron oxidation of a substrate. The excited state can also intersystem-cross from singlet to triplet and then interact with ground-state oxygen to generate singlet-oxygen, which can function as a potent oxidant. This research may result in a decreased reliance on fossil fuels by providing a route to hydrogen peroxide production, decreasing carbon emissions.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.