Oxidizing Functional Groups: Looking for New Types of Extreme Properties in Main-group Compounds

氧化性官能团，例如氮氧化物（-NO、-NO2、-ONO、-ONO 2等），多氧（-O3-、-O2-等）或多氮（-N2、-N3等）基团倾向于赋予带有它们的分子不寻常的性质。含有这些基团的化合物通常能够在热气体（N2、考克斯、H2O等）的释放下燃烧自己因此，对于分解来说，最常见的是亚稳态的，这可能是相当惊人的（爆炸性的）。这种亚稳定性通常使具有氧化基团的化合物处于存在的最边缘。除了它们的能量特性，带有氧化基团的化合物还显示出一系列其他迷人而有用的特性。氮氧化物基团是高度吸电子的，并且带有它们的化合物通常是形成弱配位阴离子的异常强的布朗斯台德酸。含二氮分子是高活性中间体和偶氮化合物的方便前体，特别是作为染料在工业规模上生产的强烈着色的化合物。含硝基和偶氮化合物显示出与光的各种相互作用，其中许多与非线性光学、荧光、磷光甚至光诱导的光致异构化有关。硝基基团也存在于许多生物活性物质中，一氧化氮是生物过程中非常重要的信号分子，显示出许多氧化官能团的巨大相关性。尽管它们的有机、金属和过渡金属化学非常发达，但氧化基团如氮氧化物和-N2官能团与第三周期和更低周期的准金属和非金属（“重”主族元素，HMG）具有非常有限的已知化学。问题的部分原因可以说是由于氮氧化物从+3氧化态到+5氧化态的可能性，例如，或者磷，铝和硅化合物等元素的强亲氧性。这些问题是对HMG氧化基团化合物的探索的挑战，但绝不会使其成为不可能，特别是当可以考虑定制方法时。基于有机含氧化基团化合物所表现出的迷人性质，我们预计它们的重主族对应物也将表现出一系列奇特的性质。我们将使用受高能材料合成，氟，无机，有机金属和主族化学启发的方法的独特组合来探索带有氧化基团的HMG化合物的合成，在未来五年内专注于以下研究轴：轴I：形成含有直接连接到HMG元素的氮氧化物官能团的主族物质（E）（RnE-NO2，RnE-ONO，RnE-ONO 2，RnE-NO，etc. E = P，Si）;轴II：主族重氮和重氮衍生物的形成（RnP-N2+和RnP-N =N）;轴III：重质苯类似物（磷杂苯，砷杂苯等）的硝化反应。

Oxidizing functional groups, such as nitrogen oxides (-NO, -NO2, -ONO, -ONO2, etc.), polyoxygen (-O3-, -O2-, etc.) or polynitrogen (-N2, -N3, etc.) groups tend to impart unusual properties to molecules that bear them. Compounds that contain these groups are often capable of burning themselves under evolution of hot gases (N2, COx, H2O, etc.) and are therefore most often metastable with respect to decomposition, which can be quite spectacular (explosive). This metastability often places compounds with oxidizing groups at the very edge of existence. Beyond their energetic character, compounds bearing oxidizing groups display a range of other fascinating and useful properties. Nitrogen-oxide-groups are highly electron-withdrawing, and compounds bearing them are often unusually strong Bronsted acids that form weakly-coordinating anions. Dinitrogen-bearing molecules are convenient precursors to highly-reactive intermediates and azo compounds, in particular, are strongly colored compounds produced on an industrial scale as dyes. Nitro and azo-containing compounds display varied interactions with light, with many of them being relevant in non-linear optics, fluorescence, phosphorescence and even light-induced photoisomerization. Nitro groups are also present in many pharmacologically active species and nitric oxide is a very important signaling molecule in biological processes, showing the tremendous relevance of many oxidizing functional groups. Despite their very well-developed organic, metal and transition-metal chemistry, oxidizing groups like nitrogen oxides and -N2 functional groups have a very limited known chemistry with metalloids and non-metals of the third period and below ("heavy" main-group elements, HMG). Part of the problem is arguably due to the possibility of going from the +3 to +5 oxidation state for pnictogens, for example, or to the strong oxophilicity of elements like phosphorus, aluminium and silicon compounds. Such issues are challenges to the exploration of HMG-oxidizing group compounds but in no way make it impossible, particularly when tailored methods can be considered. Based on the fascinating properties displayed by organic oxidizing-group-containing compounds, we expect that their heavy main-group counterparts will also display an array of exotic properties. We will use a unique combination of approaches inspired by energetic material synthesis, fluorine, inorganic, organometallic and main-group chemistry to explore the synthesis of HMG compounds bearing oxidizing groups, focusing on the following research axes in the next five years: Axis I: Formation of main-group species containing nitrogen oxide functional groups that are directly attached to the HMG element (E) (RnE-NO2, RnE-ONO, RnE-ONO2, RnE-NO, etc. E = P, Si); Axis II: Formation of main-group diazo and diazonium derivatives (RnP-N2+ and RnP=N=N); Axis III: Nitration reactions on heavy benzene analogues (phosphabenzenes, arsabenzenes, etc.).