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

铁（II）盐溶液与作为反应气体的一氧化氮（NO）反应，形成亚硝酰铁络合物。亚硝基化产物的形成可以通过光学和振动光谱来检测。液相是亚铁盐的水溶液。在与一氧化氮反应时，形成亚硝酰基-铁键，其稳定性可以通过添加共配体来调节。多齿螯合剂如乙二胺四乙酸盐（edta）诱导Fe（NO）功能对NO损失的显著电阻率。在第一个资助期内，亚硝酰铁配合物的结构化学是建立在一系列属于氨基羧酸类的共配体上的，edta也是如此。其结果是，铁（II）/aminecarboxylate/亚硝酰基复合物的类内的结构-性质的关系已成为有形的，如NO-结合的配位数变化的后果。因此，一个坚实的基础是可用于进一步发展的含铁的水相和反应气体NO的非均相反应。具体而言，未来发展的化学部分侧重于建设新的配体进一步增强性能，包括两个目标。首先，我们将尝试产生的配合物的稳定性的整体增加，以允许可靠的NO吸收在低氮氧化物分压，包括调查的气体混合物与NO作为次要成分。其次，我们将尝试实现选择性NO-过O2-结合，通过设计新的配体，完美地协调亚铁中心之前和之后NO结合。第二个问题不仅具有学术兴趣，而且解决了技术上使用的用于从烟道气中汽提NO的铁（II）/edta溶液的烦人的副反应，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，则可以使用泡罩塔技术来最终仅促进所需的NO吸收反应。在第一个供资期，已经证明，在甲醇作为溶剂的情况下，即使使用纯NO作为反应气体也可能导致竞争性反应序列，即形成铁和钴的单亚硝基或二亚硝基。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之一的选择性。总之，除了继续使用强烈着色的亚硝酰铁配合物用于鼓泡塔中反应的研究和建模之外，我们的目标是开发两个新的领域：一方面控制亚硝酰化和氧化之间的竞争，另一方面控制单亚硝酰或二亚硝酰的形成。

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.