Beyond cyanide: Future synthons based on the cyaphide and cyarside ions for the synthesis of designer magnetic coordination polymers

超越氰化物：基于氰化物和氰化物离子的未来合成子，用于合成设计师磁性配位聚合物

基本信息

批准号：
EP/T010681/1
负责人：
Jose Goicoechea
金额：
$ 53.14万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FT010681%2F1
关键词：
Beyond cyanide Future synthons based

项目摘要

The serendipitous discovery of Prussian blue by Diesbach in 1706 had an immediate revolutionary effect on the art world, and would go on to have long-lasting repercussions in many other areas of the arts and sciences. This inexpensive, non-toxic, dark blue pigment democratized the colour blue, and features in prints and paintings from artists such as Hokusai and van Gogh. Interestingly, the versatility of this compound transcends the arts, and in contrast to most other pigments, Prussian blue has also found important medical applications. Its ability to incorporate monocationic ions into its lattice makes it a powerful sequestering agent for toxic heavy metals; pharmaceutical-grade Prussian blue is used to treat individuals who have ingested poisonous thallium or radioactive caesium.Prussian Blue has a deceptively simple framework-like structure, consisting of iron metal centres (in the +2 and +3 oxidation states) that are bridged by cyanide anions along all three Cartesian axes, giving rise to an extended face-centred cubic (FCC) lattice. The modular nature of this structure allows for the variation of the metal ions, their charges, and consequently the number of unpaired electrons per metal site. By altering these variables, it is possible to access novel materials with a wealth of magnetic behaviours, all of them facilitated by strong intermetallic coupling through the cyanide ions. These structurally-related coordination polymers are commonly referred to as Prussian blue analogues (PBAs), and have found use as designer magnetic materials and, more recently, in the fields of gas sorption, hydrocarbon separation, water oxidation catalysis, and as battery components.While PBAs can be readily altered by changing the nature of the metal centres, the cyanide ion is a common building block to all of them. Attempts have been made to exploit other types of highly-conjugated cyanide-containing bridging units for the synthesis of solids, however empirically it appears that intermetallic electronic communication is most pronounced for systems based on the cyanide ion. This is in part due to the short metal-metal distances available in such compounds, but also undoubtedly related to the more densely packed and ordered FCC lattice that can be achieved with a short linear bridge. This limits further developments in the field, and places a significant design constraint on the synthesis of more complex PBAs.The goal of this project is to access novel materials related to PBAs by making use of valence isoelectronic ligands related to cyanide, such as the cyaphide and cyarside ions (where the nitrogen atom of cyanide is replaced by a phosphorus or arsenic atom, respectively). Like their lighter congener cyanide, the cyaphide and cyarside ions are ambidentate ligands capable of giving rise to close-packed structures related to Prussian blue. To date, there is no known synthetic methodology that allows for the isolation of such ions. This is the challenge we propose to address. The preference of phosphorus and arsenic for binding to heavy metals will be exploited in order to target mixed metal systems containing elements from the entirety of the periodic table. We will also extend these studies to access heteroleptic phosphorus- and arsenic-containing analogues of cyanide-based linkers such as dicyanamide and tricyanomethanide.This proposal aims to design, synthesise and study and entirely new class of extended solids related to Prussian blue with the objective of accessing new materials with potentially transformative physical and chemical properties.

1706 年迪斯巴赫偶然发现的普鲁士蓝对艺术界产生了直接的革命性影响，并将继续对艺术和科学的许多其他领域产生持久的影响。这种廉价、无毒的深蓝色颜料使蓝色变得大众化，并出现在北斋和梵高等艺术家的版画和绘画中。有趣的是，这种化合物的多功能性超越了艺术领域，与大多数其他颜料相比，普鲁士蓝还发现了重要的医学应用。其将单阳离子离子纳入其晶格的能力使其成为有毒重金属的强大螯合剂；医药级普鲁士蓝用于治疗摄入有毒铊或放射性铯的个体。普鲁士蓝具有看似简单的框架状结构，由铁金属中心（处于+2和+3氧化态）组成，铁金属中心通过桥接氰化物阴离子沿着所有三个笛卡尔轴，产生扩展的面心立方（FCC）晶格。这种结构的模块化性质允许金属离子、它们的电荷的变化，以及因此每个金属位点的不成对电子的数量。通过改变这些变量，可以获得具有丰富磁性行为的新型材料，所有这些材料都是通过氰化物离子的强金属间耦合来促进的。这些结构相关的配位聚合物通常被称为普鲁士蓝类似物 (PBA)，已被用作设计磁性材料，最近还用于气体吸附、碳氢化合物分离、水氧化催化和电池组件等领域。虽然可以通过改变金属中心的性质来轻松改变 PBA，但氰化物离子是所有 PBA 的共同组成部分。已经尝试开发其他类型的高度共轭的含氰化物桥接单元来合成固体，然而，根据经验，金属间电子通信对于基于氰化物离子的系统来说最为明显。这部分是由于此类化合物中金属-金属距离较短，但无疑也与通过短线性桥可以实现的更密集和有序的 FCC 晶格有关。这限制了该领域的进一步发展，并对更复杂的 PBA 的合成提出了重大的设计限制。该项目的目标是通过利用与氰化物相关的价态等电子配体（例如氰化物）来获得与 PBA 相关的新型材料和氰化物离子（其中氰化物的氮原子分别被磷或砷原子取代）。与它们的较轻同系物氰化物一样，氰化物和氰化物离子是双齿配体，能够产生与普鲁士蓝相关的密堆积结构。迄今为止，还没有已知的合成方法可以分离此类离子。这是我们建议解决的挑战。将利用磷和砷与重金属结合的偏好，以针对含有整个周期表元素的混合金属系统。我们还将扩展这些研究，以获取基于氰化物的连接体的杂配磷和砷类似物，例如二氰胺和三氰基甲基化物。该提案旨在设计、合成和研究与普鲁士蓝相关的全新类别的扩展固体，其目标是获取具有潜在变革性物理和化学特性的新材料。