兰州大学机构库 >化学化工学院
共价有机框架材料单晶的生长、结构及成晶机理研究
Alternative TitleSingle Crystal Growth, Structures Analyses and Crystallization Mechanism of Covalent Organic Frameworks
马天琼
Thesis Advisor王为 ; 孙俊良
2018-06-28
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword共价有机框架材料 单晶生长 结构解析 嵌套异构
Abstract

共价有机框架材料(Covalent Organic Frameworks,简称COFs)是一类新型有机多孔晶型高分子材料,由多种多样的有机小分子前体通过共价键连接而成。从2005年报道以来,COFs在气体吸附、催化、光电、储能、传感、载药等方面有着广泛的应用前景,常被认为是有机材料界的“有机分子筛”。然而,作为一种固体晶型材料,COFs的单晶一直没有被合成出来——强共价键键连、多孔性质这两大因素导致其单晶的生长极其困难。这对COFs材料的结构解析也造成巨大阻碍,很大程度上也限制了材料实际的进一步应用和长远发展。本文利用一种调制合成的方法,首次合成出COFs材料的大尺寸单晶,并利用单晶X射线衍射技术解析了COFs材料的单晶结构。在此过程中还发现了新的COFs拓扑结构(lon-b-c3)、观察到COFs的嵌套异构现象、了解了COFs的主客体化学、研究了COFs体系单晶生长的机理等。期待本工作在晶体工程、多孔材料、共价键自组装、超分子化学和主客体化学等领域能有所贡献。
    本论文第一章绪论中,综述了本领域的研究背景,例如COFs材料的结构解析现状和有关材料结晶性优化的一些研究工作等,阐明了没有单晶是COFs领域的核心瓶颈问题;第二章是COFs材料大尺寸单晶的生长和基础表征;第三章是COFs材料的单晶X-射线衍射结构解析,和小单晶的三维旋转电子衍射结构解析;第四章讨论了COFs中首次发现的嵌套异构现象,这种重要的超分子异构现象,代表着自然世界物质的多样性,也丰富了嵌套异构的材料类型;为了更好地研究三维COFs中最普遍的金刚石嵌套结构,在第四章研究的同时我们还推导了一个具有普适意义的公式来计算金刚石嵌套结构的嵌套层数,相关内容在第五章讨论;第六章研究了COFs不同异构体在客体分子作用下的结构变化,并第一次用单晶X-射线衍射的手段观测到水作为客体分子在主体材料COFs中的位置和与主体的相互作用;第七章我们进一步推广了自己单晶生长的方法,实现了不同晶粒尺寸COFs单晶的可控生长;在单晶生长和可控尺寸生长的实验基础上,第八章我们结合质谱、核磁等分析手段,探究了COFs材料的成晶过程,提出了通过亚胺交换反应、构建组合化学反应库来控制COFs材料成核和生长的机理。有了对亚胺键COFs的深刻理解和认识,第九章我们进一步研究了亚胺键COFs的还原和氧化,以期得到更加稳定的COFs材料并实现单晶到氧化单晶的转化。第十章为本文结论。这一系列工作打破了共价键最不容易生长单晶的传统认识,体现了对超分子自组装的一种可控能力,并开辟了COFs材料领域一个全新的研究方向,也将对未来COFs材料的结构、性质、应用研究等各个方面产生深远的影响。

Other Abstract

Covalent organic frameworks (COFs) represents a new class of crystalline porous organic polymers, the structures of which are diversely constructed via the covalent bonding of pre-designed organic monomers. Most research in this fascinating area has been focusing on applications such as gas sorption, catalysis, photoelectricity, energy storage, sensor, drug delivery etc, then it can be served as “organic zeolites” in organic material. However, as a solid crystalline material, single crystals of COFs haven’t been obtained since the first report from 2005. In difference from hydrogen or coordination bonding, strong covalent-bonding and porosity are the significant obstacle in growing single crystals. Therefore, structure solution and reality of further application were hindered. Powder X-ray diffraction and advanced electron diffraction analyses were usually used to determine the COF structures based on reticular chemistry and topology analysis, but many of their structures are still ambiguous. In this contribution, we developed a modulator method to obtain large single-crystal COFs, and the single-crystal X-ray diffraction structures of COFs are reported here first time. In this process, a new topology of lon-b-c3 was explored, and the interpenetration isomerism in COFs was also observed. Furthermore, host-guest chemistry in COFs was confirmed. On this basis, the crystallization mechanism can be studied. We hope our work can contribute to the field of crystal engineering, porous material, covalent self-assembly, supramolecular chemistry, host-guest chemistry, and so on.
  In this thesis, we reviewed research background such as structure determination and crystallinity improvement for COFs in chapter 1; in chapter 2 we reported the growth of large single-crystal COFs and their characterization; chapter 3 is about single-crystal X-ray diffraction structure determination; chapter 4 is observation of interpenetration isomerism, which can occur as a vivid example of diversity and is one of supramolecular isomerism. This work provides a novel example to the category of interpenetration isomerism. In order to know interpenetrated dia-structure better, we further deduced a general formula to calculate the interpenetration degree of dia-based COF structures in chapter 5. The interpenetrated isomers possess their different structure flexibilities with them, and we also observed host-guest effect between water and COF framework by single-crystal X-ray diffraction, all of these were talked in chapter 6. Furthermore, by generalizing the synthetic method, controllable synthesis of different-sized COF crystals was shown in chapter 7; and exploring of crystallization mechanism in chapter 8 resulted in a conclusion that, imine exchange reaction in the combinatorial library we built is benefit to nucleation and growth of single-crystal COFs. In chapter 9, we studied the reduction and oxidation of imine bonds in COFs to access more stable COFs, and realize a single-crystal-to-single-crystal process in COFs.

We believe our work not only breaks traditional thinking for making a covalent crystals, but also sheds new lights to the further development of COFs. These works will have profound impact on structural investigation, structure-performance relationship, and the universal acknowledge for future application of COFs.

URL查看原文
Language中文
Document Type学位论文
Identifierhttp://ir.lzu.edu.cn/handle/262010/237751
Collection化学化工学院
Recommended Citation
GB/T 7714
马天琼. 共价有机框架材料单晶的生长、结构及成晶机理研究[D]. 兰州. 兰州大学,2018.
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