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Solid-state nuclear magnetic resonance of paramagnetic systems, graphite materials and amyloid peptide.

机译：顺磁性系统，石墨材料和淀粉样蛋白肽的固态核磁共振。

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摘要

Solid-State NMR (SSNMR) has been widely used as an important tool to characterize and identify organic compounds and biological systems. However, applications of high-resolution SSNMR to paramagnetic systems have been very limited because paramagnetic compounds often exhibit severe line broadening and large paramagnetic shifts. Recently, our group developed a new approach using very fast magic angle spinning (VFMAS) to study and characterize different paramagnetic compounds and other materials. This has opened an avenue to obtain structural information for different paramagnetic systems by 1H and 13C SSNMR. The work in this thesis demonstrates the applications of VFMAS to three classes of systems.;First, we applied the VFMAS techniques to paramagnetic polymorphs of Cu(II)(quinolinole)2, Cu(II) (Imidazole)2 and Cu(II) phthalocyanine. We were able to distinguish between these polymorphs both qualitatively and quantitatively. Assignments of these polymorphs were obtained experimentally and confirmed by ab-initio calculations.;Secondly, we utilized the properties of paramagnetic molecules, which often have short 1H T1 relaxation time, in order to increase the sensitivity of 13C SSNMR for non paramagnetic biomolecules using VFMAS methods. We specifically examined the application of doping paramagnetic CuEDTA molecules to the amyloid intermediate species found in misfolding of Abeta(1-40) peptide into amyloid fibrils. A 7 fold reduction of an experimental time was obtained with the use of small amounts of CuEDTA in 1D and 2D 13C SSNMR for the Abeta intermediate. Simple measurements of paramagnetic 13C T 1 relaxation rate enhancement to obtain supermolecular information for the Abeta(1-40) intermediates were also performed.;Third, we examined the possibility of obtaining structural information for amorphous graphene- and graphite-based materials using SSNMR methods. 13C labeled graphite oxide (GO) was used as a model system of these chemically modified graphenes. The detailed chemical structure of GO was revealed by our VFMAS methods. Qualitative and quantitative analysis for 13 C naturally abundant graphite nano-fibers by 13 C high resolution VFMAS SSNMR was also demonstrated. As a result of these studies, we believe that our VFMAS SSNMR methods can be widely used to study various systems ranging from polymorphs of large paramagnetic systems to non-paramagnetic biological macromolecules and nano-materials.
机译：固态NMR（SSNMR）已被广泛用作表征和鉴定有机化合物和生物系统的重要工具。但是，高分辨率SSNMR在顺磁系统中的应用非常有限，因为顺磁性化合物通常会出现严重的谱线展宽和较大的顺磁性位移。最近，我们的小组开发了一种使用超快速魔角旋转（VFMAS）的新方法来研究和表征不同的顺磁性化合物和其他材料。这为通过1H和13C SSNMR获得不同顺磁系统的结构信息开辟了一条途径。本文的工作证明了VFMAS在三类系统中的应用。首先，我们将VFMAS技术应用于Cu（II）（quinolinole）2，Cu（II）（Imidazole）2和Cu（II）的顺磁多晶型酞菁。我们能够定性和定量地区分这些多晶型物。这些多晶型物的分配是通过实验获得的，并通过从头算得到了证实。其次，我们利用顺磁性分子的特性（通常具有短的1H T1弛豫时间），以提高使用VFMAS的13C SSNMR对非顺磁性生物分子的敏感性。方法。我们专门检查了将顺磁性CuEDTA分子掺杂到淀粉样中间产物中的应用，该中间物在Abeta（1-40）肽错误折叠成淀粉样原纤维中发现。使用少量的CuEDTA以1D和2D 13C SSNMR进行Abeta中间体实验，实验时间减少了7倍。还进行了顺磁性13C T 1弛豫速率增强的简单测量，以获得Abeta（1-40）中间体的超分子信息。第三，我们研究了使用SSNMR方法获得基于非晶石墨烯和石墨的材料的结构信息的可能性。 。将13C标记的氧化石墨（GO）用作这些化学改性石墨烯的模型系统。我们的VFMAS方法揭示了GO的详细化学结构。还证明了通过13 C高分辨率VFMAS SSNMR对13 C自然丰富的石墨纳米纤维进行定性和定量分析。这些研究的结果是，我们相信我们的VFMAS SSNMR方法可以广泛用于研究各种系统，从大型顺磁性系统的多晶型到非顺磁性生物大分子和纳米材料。

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  • 作者

    Shaibat, Medhat Awadallah.;

  • 作者单位

    University of Illinois at Chicago.;

  • 授予单位 University of Illinois at Chicago.;
  • 学科 Chemistry Analytical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 172 p.
  • 总页数 172
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

  • 入库时间 2022-08-17 11:38:24

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