Functional Organic Solid State Materials Derived from Designer Host Frameworks

本项目主要研究分子基功能材料的设计与合成。基于层状胍-有机二磺酸盐宿主框架的包合化合物，其中有机二磺酸盐“支柱”连接相反的胍离子(G)和磺酸基团(S)的氢键片以产生包合腔，由于GS片的结构坚固性，在这方面表现出非凡的能力，它可以作为“超分子构建块”。该项目将重点合成定制的GS宿主框架，并赋予包含腔，用于特定识别选定的客体分子和控制功能客体分子的排序。这项工作还将利用我们最近发现的基于有机单磺酸盐的片状GS包合化合物，以及我们更令人惊讶的圆柱形包合化合物的发现，其中准六方胍-有机单磺酸盐片包裹在模板客体分子周围，形成氢键“纳米管”。本工作的具体目标包括：(i)从多种手性有机二磺酸柱中合成手性GS宿主，目的是开发用于手性化合物的对映选择性分离的宿主，并探测手性在固态中的传递；（ii）通过不对称和香蕉形支柱引导的组装来合成极性主机框架，并检查主机结构对客人订购的影响；（iii）阐明导致胍类有机单磺酸盐片柱异构体的因素，包括填料受挫的作用，这是表面活性剂和嵌段共聚物微观结构中经常使用的概念；（iv）通过与三磺酸盐镶嵌合成坚固的氢键圆柱体；完成了从胍类有机单磺酸盐衍生的新型热致液晶相的结构和性质的研究。有几个机制可以确保这个项目产生广泛的影响，包括(i)通过UMN材料研究科学与工程中心，为本科生和教师提供暑期研究经验，其中许多来自少数民族服务机构，以及为高中教师开发围绕晶体结构的课程工具，（ii）为研究生和博士后提供指导机会，（iii）与其他美国和国际机构的科学家合作，包括由Brain Korea-21 （BK-21）计划赞助的韩国机构的访问研究生，（iv）对中西部文理学院化学教师协会（MACTLAC）的四年制学院进行研讨会访问，（vi）通过出版物，会议和在我们集团网站上发布成果向科学界传播，（vii）期望在《化学教育杂志》上发表一篇关于“设计晶体”主题的手稿（受邀），并附带用于可视化自组装和晶体结构的电子媒体。在固态化学中最重要的挑战之一是设计和合成有机晶体——分子在晶格中组装——具有规定的结构，这一学科通常被称为“晶体工程”。这项研究使用分子作为“修补玩具”，旨在形成开放的晶体框架，在许多方面类似于预制建筑，其中包含由功能性物品占用的空办公室，在我们的案例中，“客人”分子具有一些有用的属性或功能。除了探索引导分子组装成晶格的基本原理之外，这项研究的特定目标包括能够分离手性异构体的框架，这构成了美国制药工业1000亿美元的组成部分，能够将光的频率加倍的有机材料可能在电信技术中找到潜在的应用，设计晶体和聚合物的新型复合材料可以提供重量轻但机械强度高的塑料，可能应用于汽车和食品包装行业。这些材料的分子性质在这些应用中提供了实质性的优势，无论是性能的改进还是加工成本的降低。这些目标的实现将对公共卫生和对美国经济至关重要的关键技术产生重大影响。该研究还旨在为新兴的年轻科学家和工程师提供应对材料研究新挑战所需的技能，同时加强国际互动，特别是与韩国主要机构和著名学术机构的学生的互动。该项目由材料研究部和化学部共同资助。

This project focuses on the design and synthesis of molecular-based functional materials. Inclusion compounds based on lamellar guanidinium-organodisulfonate host frameworks, in which organodisulfonate "pillars" connect opposing hydrogen-bonded sheets of guanidinium cations (G) and sulfonate moieties (S) to generate inclusion cavities, exhibit a extraordinary capacity in this regard owing to the structural robustness of the GS sheet, which serves as a "supramolecular building block." The project will emphasize the synthesis of customized GS host frameworks endowed with inclusion cavities designed for specific recognition of select guest molecules and controlled ordering of functional guest molecules. The work will also capitalize on our recent discovery of lamellar GS inclusion compounds based on organomonosulfonates, and our even more surprising discovery of cylindrical inclusion compounds, wherein quasihexagonal guanidinium-organomonosulfonate sheets wrap around templating guest molecules to form hydrogen bonded "nanotubes." Specific objectives of this work include: (i) the synthesis of chiral GS hosts derived from a diverse library of chiral organodisulfonate pillars, with the aim of developing hosts for enantioselective separations of chiral compounds and probing the transmission of chirality in the solid state; (ii) the synthesis of polar host frameworks through assembly guided by asymmetric and banana-shaped pillars and examination of the effect of host structure on guest ordering; (iii) elucidation of the factors responsible for lamellae-cylinder isomerism in guanidinium organomonosulfonates, including the role of packing frustration, a concept often used in surfactant and block copolymer microstructures; (iv) the synthesis of robust hydrogen-bonded cylinders through tessellation with trisulfonates; and (v) completion of work aimed at elucidating the structure and properties of new thermotropic liquid crystal phases derived from guanidinium organomonosulfonates. Several mechanisms exist to ensure broad impact of this project, including (i) through the UMN Materials Research Science and Engineering Center, summer research experiences for undergraduates and teachers, many from minority-serving institutions, and the development of curriculum tools for high school teachers revolving around crystal structure, (ii) mentoring opportunities for graduate students and postdocs, (iii) several collaborations with scientists from other U.S. and international institutions, including visiting graduate students from Korean institutions sponsored by the Brain Korea-21 (BK-21) program, (iv) seminar visits to four-year colleges in the Midwest Association of Chemistry Teachers in Liberal Arts Colleges (MACTLAC), (vi) dissemination of outcomes to the scientific community through publications, conferences, and postings on our group web site, and (vii) anticipated publication of a manuscript (invited) in the Journal of Chemical Education on the topic of "designer crystals," accompanied by electronic media for visualizing self-assembly and crystal structures.%%%One of the foremost challenges in solid state chemistry is the design and synthesis of organic crystals - molecules assembled in lattices - with prescribed architectures, a discipline often referred to as "crystal engineering." This research employs molecules as "tinkertoys" that are designed to form open crystal frameworks that in many ways resemble prefabricated buildings containing empty offices equipped for occupation by functional items, in our case "guest" molecules having some useful property or function. In addition to exploring the fundamental principles underlying the guided assembly of molecules into crystal lattices, particular targets of this research include frameworks able to separate chiral isomers, which constitute a $100 billion component of the U.S. pharmaceutical industry, organic materials capable of doubling the frequency of light that may find potential applications in telecommunication technologies, and new composites of designer crystals and polymers that can provide lightweight but mechanically strong plastics with possible applications in the automotive and food packaging industries. The molecular nature of these materials offers substantial advantages in each of these applications with respect to either more improved properties or reduced processing costs. The achievement of these aims can have substantial impact on public health and key technologies that are vital to the U.S. economy. The research is also designed to equip emerging young scientists and engineers with the skills required to tackle new challenges in materials research while enhancing international interactions, particularly with key institutions and students from notable academic institutions in South Korea. This project is co-funded by the Division of Materials Research and the Chemistry Division.