In-situ characterisable nitrosyl-iron complexes with controllable reactivity in multiphasic reaction media

在多相反应介质中具有可控反应性的原位表征亚硝酰基铁配合物

• 批准号: 256760414
• 负责人: Professor Dr. Peter Klüfers
• 金额: --
• 依托单位: Lehrstuhl für Bioanorganische Chemie und Koordinationschemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2014
• 资助国家: 德国
• 起止时间: 2013-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/256760414?language=en
• 关键词: situ; characterisable; nitrosyl; iron; complexes

Iron(II) salt solutions react with nitric oxide (NO) as a reactive gas under formation of nitrosyliron complexes. The formation of the nitrosylated products can be detected by optical and vibrational spectroscopy. The liquid phase is an aqueous solution of a ferrous salt. On reaction with nitric oxide, a nitrosyl-iron linkage is formed, the stability of which can be adjusted by the addition of co-ligands. Multidentate chelators such as ethylenediaminetetraacetate (edta) induce pronounced resistivity of the Fe(NO) functions towards NO loss. In the first funding period, the structural chemistry of nitrosyliron complexes was established for a series of co-ligands that belong to the class of aminecarboxylates, as does edta. As a result, structure-property relationships within the class of iron(II)/aminecarboxylate/nitrosyl complexes have become tangible, such as the consequences of coordination-number changes on NO-binding. Thus, a solid basis is available to further develop the heterogeneous reaction of an iron-containing aqueous phase and the reactive gas NO. Specifically, the chemical part of future development focuses on the construction of new ligands with further enhanced properties and includes two goals. First, we will attempt to produce an overall increase of the complexes' stability to allow for reliable NO absorption at low nitric-oxide partial pressures to include the investigation of gas mixtures with NO as the minor component. Second, we will try to achieve selective NO- over O2-binding by designing new ligands that perfectly coordinate the ferrous centres before and after NO binding. This second issue is not only of academic interest but addresses an annoying side-reaction of technically employed iron(II)/edta solutions used for the stripping of NO from flue-gas streams, namely the irreversible oxidation of the iron(II) reagent to the iron(III) oxidation state. If we succeed in repressing the irreversible oxidation by the optimisation of chemical parameters, bubble-column technology may be used to finally promote solely the desired NO absorption reaction. In the first funding period, it was demonstrated that, in methanol as the solvent, even the use of pure NO as the reactive gas could result in competing reaction sequences, namely the formation of either mononitrosyls or dinitrosyls of iron and cobalt. We plan to develop a reaction system that allows us to study the selectivity towards one of the two reactions by the variation of bubble-column parameters. In summary, besides continuing to use the intensely coloured nitrosyliron complexes for the study and modeling of the reactions in bubble columns, we aim to develop two new fields: the control of the competition between nitrosylation and oxidation on the one hand, and the control of the formation of either mononitrosyls or dinitrosyls on the other.

铁(II)盐溶液与一氧化氮(NO)以反应气体的形式反应，生成亚硝基络合物。亚硝化产物的形成可以通过光学和振动光谱来检测。液体是亚铁盐的水溶液。与一氧化氮反应，形成亚硝基-铁键，其稳定性可通过添加共配体来调节。多齿螯合剂如乙二胺四乙酸酯(EDTA)可使Fe(NO)的功能向亚硝酸根转移。在第一个资助期，与EDTA一样，建立了属于氨基羧酸盐类的一系列共配体的亚硝基络合物的结构化学。因此，铁(II)/氨基羧酸盐/亚硝基络合物的结构-性质关系已经变得明显，例如配位数变化对非结合的影响。从而为进一步开展含铁水相与反应气体NO的非均相反应提供了坚实的基础。具体地说，未来发展的化学部分侧重于构建具有进一步增强性质的新配体，并包括两个目标。首先，我们将尝试全面提高络合物的稳定性，以允许在低一氧化氮分压下可靠地吸收NO，包括研究以NO为次要成分的混合气体。其次，我们将尝试通过设计新的配体来实现选择性的无过氧结合，在没有结合之前和之后完美地协调铁中心。第二个问题不仅具有学术意义，而且涉及用于从烟气中脱除NO的技术上使用的铁(II)/EDTA溶液的一个恼人的副反应，即铁(II)试剂不可逆氧化为铁(III)氧化态。如果我们通过优化化学参数成功地抑制了不可逆氧化，则可以利用鼓泡塔技术最终仅促进所需的NO吸收反应。在第一个供资期间，已经证明，在以甲醇为溶剂的情况下，即使使用纯NO作为反应气体，也可能导致相互竞争的反应顺序，即形成铁和钴的一硝基或二亚硝基。我们计划开发一个反应系统，使我们能够通过改变鼓泡塔参数来研究对两个反应中的一个反应的选择性。综上所述，除了继续利用浓色亚硝基络合物来研究和模拟鼓泡塔中的反应外，我们的目标是开发两个新的领域：一方面控制亚硝化和氧化之间的竞争，另一方面控制一硝基或二亚硝基的生成。