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

氧化官能团，如氮氧化物（- no, - no2, - ono， - ono2等），多氧（- o3 -， - o2 -等）或多氮（- n2， - n3等）基团往往赋予承载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, COx， H2O等）的演化下燃烧自己，因此在分解方面通常是亚稳态的，这可能是相当壮观的（爆炸性的）。这种亚稳性常常使具有氧化基团的化合物处于存在的边缘。除了它们的能量特征之外，含有氧化基团的化合物还显示出一系列其他令人着迷和有用的特性。氮氧化物基团具有高度的吸电子性，携带它们的化合物通常是异常强的布朗斯特德酸，形成弱配位阴离子。含二氮分子是高活性中间体和偶氮化合物的方便前体，特别是在工业规模上作为染料生产的强颜色化合物。含硝基和偶氮化合物与光表现出不同的相互作用，其中许多与非线性光学、荧光、磷光甚至光致异构化有关。硝基也存在于许多具有药理活性的物种中，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，与第三期及以下的类金属和非金属（“重”主族元素，HMG）的化学作用非常有限。这个问题的部分原因可能是，例如，致烟剂可能从+3氧化态变为+5氧化态，或者磷、铝和硅化合物等元素具有很强的亲氧性。这些问题是探索hmg氧化基团化合物的挑战，但绝不是不可能的，特别是当可以考虑量身定制的方法时。基于有机含氧化基化合物所显示出的令人着迷的性质，我们期望它们的重主基对应物也会显示出一系列奇特的性质。我们将以含能材料合成、氟化学、无机化学、有机金属化学和主基团化学为灵感，采用独特的方法，探索含氧化基团的HMG化合物的合成，未来5年将重点研究以下几个方向：轴一：形成直接与HMG元素(E)相连的含氮氧化物官能团的主基团（RnE-NO2、RnE-ONO、RnE-ONO2、RnE-NO等）。E = P, Si)；轴II：主基团重氮和重氮衍生物的形成（RnP- n2 +和RnP=N=N）；轴三：重苯类似物（磷苯、苯甲酸苯等）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.).