Synthesis of Main Group Compounds and Materials with Novel Structures and Optoelectronic Properties

在化学系化学合成计划的支持下，凯斯西储大学化学系的John Protasiewicz教授和他的学生正在制备含有P=C的扩展pi电子系统的化合物。P=C单元的加入允许对材料的光学和电学性质进行调整，以便最大限度地提高材料的性能。这些研究的动机是需要经济的手段来制造高效的照明和显示器。利用廉价和丰富的元素以及将浪费和有毒副产品的形成降至最低的方法特别有吸引力。该项目设想了低成本/轻质/可加工塑料的制备以及与发光技术相关的材料。例如，聚合物、分子电子学、发光二极管、光伏和柔性电子学。作为这项研究计划的一部分，接受培训和教育的学生正在为进入未来的工业和教育领域的熟练劳动力做准备。除了与先进制造相关的更广泛的技术影响外，Protasiewicz教授还将共同组织和实施旨在提高研究生和教师对心理健康问题的认识的项目。将合成具有反应性的主组系统，并询问它们的光物理性质，以推进和创建主组光物理化学的新范式。这项工作探索了几个相互关联的研究线索，灵感来自于以前对发光1，3-苯并氧膦和1，3-苯并氮磷的研究。一类新的具有P=C键的光致发光化合物(膦-天青烯)将被制备来显示来自S2(而不是S1)激发态的荧光，从而打破了Kasha规则。抗Kasha化合物很少见，并且具有理想的光物理性质。N-杂环卡宾和荧光仲胺之间的非传统氢键将被用来发展二卡宾的超分子化学，这种超分子化学可以与含有两个NH官能团的荧光团发生氢键作用，这将为开发可作为选择性应用的开启荧光传感器的材料提供新的机会。以前的研究还发现了一个不寻常的反应，将邻膦苯酚转化为苯二氧磷。这一过程包括去除6个氢原子并形成新的PP和PO键。这一过程将扩展到其他类型的键，并将尝试使这一过程具有催化作用。这项研究中将要开发的无金属系统不再是以前报道的基于昂贵和/或有毒过渡金属的策略，而是专注于毒性较小、稀土含量较高的元素。总而言之，这些努力旨在推进和展示主要族元素可以为更大的光电子和结构材料领域提供的优势。该奖项反映了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。

With the support of the Chemical Synthesis program of the Division of Chemistry, Professor John Protasiewicz and his students at the Department of Chemistry at Case Western Reserve University are preparing compounds with P=C-containing extended pi-electron systems. The inclusion of P=C units permits the optical and electronic properties of the material to be tuned in order to maximize the behavior of the material. A motivation for these studies is a need for economical means to manufacture highly efficient lighting and displays. Methods that utilize inexpensive and abundant elements and ones that minimize the formation of wasteful and toxic byproducts are especially attractive. This project envisions the preparation of low cost/lightweight/processable plastics and materials related to light emitting technology. Examples, include polymers, molecular electronics, light emitting diodes, photovoltaics, and flexible electronics. The students trained and educated as part of this research program are being prepared to enter tomorrow's skilled workforce in industry and education. In addition to the technical broader impacts related to advanced manufacturing, Professor Protasiewicz will co-organize and run programs directed at raising awareness of mental health issues among graduate students and faculty.Reactive main group systems will be synthesized and their photophysical properties interrogated to advance and create new paradigms in main group photophysical chemistry. This work explores several interconnected research threads, inspired from previous studies on luminescent 1,3-benzoxaphospholes and 1,3-benzazaphospholes. A new class of photoluminescent compounds (phospha-azulenes) bearing P=C bonds will be prepared to display fluorescence from the S2 (not S1) excited state, thus breaking Kasha's rule. Anti-Kasha compounds are rare and have desirable photophysical properties. Unconventional hydrogen bonding between N-heterocyclic carbenes and fluorescent secondary amines will be exploited to develop the supramolecular chemistry of dicarbenes that can undergo hydrogen bonding to a fluorophores containing two NH functional groups, which will offer new opportunities to develop materials that could act as turn-on fluorescent sensors for select applications. Previous studies also uncovered an unusual reaction that converts ortho-phosphinophenol to benzodioxaphosphole. This process involves removing 6 hydrogen atoms and making new PP and PO bonds. This process will be extended to other types of bonds and and attempts will be made to make the process catalytic. The metal-free systems to be developed in this research move away from previously reported strategies based on expensive and/or toxic transition metals and concentrates on elements that are less toxic and more earth abundant. Combined, these efforts aim to advance and showcase the advantages that main group elements can offer to the greater field of optoelectronic and structural materials.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.