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Synthesis of inorganic heptazine-based materials.

机译：合成基于无机庚嗪的材料。

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摘要

This dissertation describes research on the synthesis and characterization of extended heptazine-based, graphite-like carbon nitride materials (CN x), as well as molecular heptazine (C6N7) derivatives. Spurred on by recent triazine to heptazine conversion studies, a structural examination was performed on an amorphous nitrogenrich carbon nitride material formed via the rapid and exothermic self-propagating decomposition of a triazine (C3N3) precursor, trichloromelamine (TCM). The thermally stable and insoluble CNxHy product was determined to be composed of heptazine repeat units. This conclusion was supported by 13C solid state NMR and isolation of molecular heptazine anions after base hydrolysis (structural deconstruction) of the CNxHy material.;Modifications to the decomposition of TCM were explored. Introduction of a solid template (NaCl or silica) led to morphological changes in the TCM-CN x product, observed by scanning electron microscopy. It was found that the sodium salts, NaBr and NaN3, led to chloride exchange with TCM. The use of mixtures of NH4Cl and NaN3 also showed changes in the morphology of the material, while leading to slight changes in the IR spectra. A series of reactions between NaBH4 and TCM yield novel thermally stable boron carbon nitride (BCN) materials. Reactions between TCM and Li 2C2 or aromatic organic solids led to CN x materials with increased carbon contents.;Crystalline metal-heptazine precipitates were generated by cation exchange reaction with the base hydrolysis product of TCM-CNx, potassium cyamelurate. A structure solution was attempted for the crystalline copper cyamelurate salt, KCu[C6N7O3]˙4H 2O. Neutral molecular heptazines were also synthesized; these species included 2,5,8-tribromo-s-heptazine (TBH), 2,5,8-triphenyl-s-heptazine (TPH), 2,5,8-2 tris(diisopropylamino)-s-heptazine (TAmH), and 2-bis(trimethylsilyl)amido-5,8-dichloroheptazine (DCAH). These materials were sublimable and showed interesting optical absorption and emission properties. A polymeric heptazine material was synthesized by thermal decomposition of DCAH.;Several attempts were made to synthesize polymeric materials from heptazine precursors. Extended solids with C6N8 and C9N 7 stoichiometry were made through solid state metathesis reactions between trichloroheptazine and either lithium nitride or lithium carbide. Powder X-ray diffraction indicated that salt formation was occurring during these reactions and products had the desired stoichiometry by elemental analysis. It was generally observed that CNx materials containing excess carbon displayed increased thermal stability when compared to pure CNx.
机译：本文介绍了扩展的基于庚嗪的类石墨氮化碳材料（CN x）以及分子庚嗪（C6N7）衍生物的合成和表征的研究。在最近的三嗪到庚嗪转化研究的推动下，对通过无定形的富氮氮化碳材料进行了结构检查，该材料是通过三嗪（C3N3）前体三氯三聚氰胺（TCM）的快速放热自蔓延分解而形成的。确定热稳定且不溶的CNxHy产物由庚嗪重复单元组成。该结论得到13 C固态NMR和CNxHy材料的碱水解（结构解构）后分子庚嗪阴离子的分离的支持。；研究了中药分解的修饰方法。通过扫描电子显微镜观察，引入固体模板（NaCl或二氧化硅）导致TCM-CN x产品的形态发生变化。发现钠盐NaBr和NaN3导致与TCM进行氯离子交换。 NH4Cl和NaN3的混合物的使用也显示了材料形态的变化，同时导致IR光谱略有变化。 NaBH4和TCM之间的一系列反应产生了新型的热稳定氮化硼碳（BCN）材料。 TCM与Li 2C2或芳族有机固体之间的反应导致CN x材料的碳含量增加。;与TCM-CNx的碱水解产物cyamelurate钾盐进行阳离子交换反应，生成了结晶金属庚烷沉淀。试图对结晶的氰尿酸铜盐KCu [C6N7O3]·4H 2O进行结构解。还合成了中性分子庚嗪。这些物种包括2,5,8-三溴-s-庚嗪（TBH），2,5,8-三苯基-s-庚嗪（TPH），2,5,8-2三（二异丙基氨基）-s-庚嗪（TAmH ）和2-双（三甲基甲硅烷基）酰胺基5,8-二氯庚嗪（DCAH）。这些材料是可升华的，并显示出令人感兴趣的光学吸收和发射特性。通过DCAH的热分解合成了聚合的庚嗪材料。进行了多次尝试从庚嗪前体合成聚合材料的尝试。通过三氯庚嗪与氮化锂或碳化锂之间的固态复分解反应可制得化学计量为C6N8和C9N 7的扩展固体。粉末X射线衍射表明在这些反应期间发生了盐的形成，并且通过元素分析，产物具有所需的化学计量。通常观察到，与纯CNx相比，含过量碳的CNx材料显示出更高的热稳定性。

著录项

  • 作者

    Holst, James Robert.;

  • 作者单位

    The University of Iowa.;

  • 授予单位 The University of Iowa.;
  • 学科 Chemistry General.;Chemistry Inorganic.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 217 p.
  • 总页数 217
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;无机化学;
  • 关键词

  • 入库时间 2022-08-17 11:38:24

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