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首页> 外文期刊>Chemistry: A European journal >Big, Strong, Neutral, Twisted, and Chiral pi Acids
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Big, Strong, Neutral, Twisted, and Chiral pi Acids

机译：大，强，中性，扭曲和手性pi酸

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General synthetic access to expanded -acidic surfaces of variable size, topology, chirality, and acidity is reported. The availability of surfaces with these characteristics is essential to develop the functional relevance of anion- interactions with regard to molecular recognition, translocation, and transformation. The problem is that, with expanded surfaces, the impact of electron-withdrawing substituents decreases and the high acidity needed for strong anion- interactions can be more difficult to obtain. To overcome this problem, it is herein proposed to build large surfaces from smaller fragments and connect these fragments with bridges that are composed only of single atoms. Two central surfaces for powerful anion- interactions, namely, perfluoroarenes and naphthalenediimides (NDIs), were selected as fragments and coupled with through sulfide bridges. Their oxidation to sulfoxides and sulfones, as well as fluorine substitution in the peripheral rings, provides access to the full chemical space of relevant acidities. According to cyclic voltammetry, LUMO levels range from -3.96 to -4.72eV. With sulfoxide bridges, stereogenic centers are introduced to further enrich the intrinsic planar chirality of the expanded surfaces. The stereoisomers were separated by chiral HPLC and characterized by X-ray crystallography. Their topologies range from chairs to boats, and the latter are reminiscent of the cation- boxes in operational neuronal receptors. With pentafluorophenyl acceptors, the acidity of NDIs with two sulfoxide groups in the core reaches -4.45eV, whereas two sulfone moieties give a value of -4.72eV, which is as low as with four ethyl sulfone groups, that is, a superacid near the limit of existence. Beyond anion- interactions, these conceptually innovative -acidic surfaces are also of interest as electron transporters in conductive materials.
机译：据报道，一般可以合成到具有可变大小，拓扑，手性和酸性的膨胀酸性表面。具有这些特征的表面的可用性对于发展阴离子相互作用在分子识别，易位和转化方面的功能相关性至关重要。问题在于，随着表面的扩大，吸电子取代基的影响降低，并且更难获得强阴离子相互作用所需的高酸度。为了克服该问题，本文提出了用较小的碎片构建大表面，并将这些碎片与仅由单个原子组成的桥连接。选择两个能进行强力阴离子相互作用的中心表面，即全氟芳烃和萘二酰亚胺（NDI）作为碎片，并通过硫化物桥连接。它们被氧化为亚砜和砜，以及在外围环中被氟取代，从而可以进入相关酸度的整个化学空间。根据循环伏安法，LUMO水平为-3.96至-4.72eV。通过亚砜桥，引入了立体异构中心，以进一步丰富扩展表面的固有平面手性。通过手性HPLC分离立体异构体，并通过X射线晶体学表征。它们的拓扑结构从椅子到船不等，后者使人联想到可操作的神经元受体中的阳离子盒。使用五氟苯基受体时，核心中带有两个亚砜基的NDI的酸度达到-4.45eV，而两个砜部分给出的值为-4.72eV，该值与四个乙基砜基团的值低，即在存在的极限。除了阴离子相互作用之外，这些概念上创新的酸性表面还作为导电材料中的电子传输体而受到关注。

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