Mapping the chemistry of phosphorus-containing analogues of urea. From fundamental chemistry to high-performance compounds and materials.

等球体的类比经常被用来比较小的无机分子和更成熟的有机物种的基本化学。例如，甲基片段（C-H）和磷之间的对角线关系导致后者被戏称为“碳副本”。这导致了广泛的化学旨在开发含磷的有机分子类似物，如磷酸烯烃（RP=PR）和-炔（PCR），以及许多其他例子。然而，等球体关系并不意味着特定有机分子的含磷同系物可以很容易地合成。事实上，用磷原子代替碳氢单元，甚至是氮等电子元素，来合成相对简单的分子，仍然是一项重大的技术和智力挑战。在这方面，合成无机化学远远落后于有机合成。举个例子，虽然尿素在1829年首次被合成分离出来，但直到2013年底，我们的研究小组才成功地分离出磷的类似物phosphinecarboxamide。考虑到尿素作为化学原料的重要性，我们建议利用这种较重的类似物（和其他相关物种）来合成新的分子和固体。这是一种全新的有机磷化合物的方法，虽然具有固有的风险，但有可能产生令人着迷的新物种，这些新物种与尿素衍生的物种有关，但它们具有根本不同的化学和物理性质。目前合成含磷化学品的方法（例如用于制药和特殊化学品，如光引发剂）需要使用氯化磷作为原料。虽然这些过程目前代表了工业的最新技术，但使用替代的无毒前体仍然是一个非常理想的目标。基于白磷的化学活化的有机磷化合物的替代策略是可能的（并且在文献中有充分的记录），但是这种转化通常因低选择性而受到损害，或者需要多次后续操作才能与工业过程竞争。此外，白磷本身具有很强的焦性，操纵起来很危险。与这些前体相关的风险使得鉴定新的磷原子原料非常必要。我们建议开发一类新的含磷小分子的化学，可以使用红磷，元素的非焦性同素异形体。最终，这将使我们能够减少在操纵合成特种化学品的传统前体时通常遇到的安全风险。基于我们实验室最近的突破，我们将探索2-磷酸乙酯阴离子和磷酸乙酰胺的化学性质，这是两种新的含磷类似物，它们是无处不在的化学物质（分别是氰酸盐离子和尿素）。我们的最终目标是获得具有催化，化学传感和材料化学潜在应用的新型分子，超分子和聚合物物种。这一提议代表了一种全新的方法来开发具有巨大潜在社会和经济影响的含磷分子和固体。

The isolobal analogy is frequently invoked to draw comparisons between the fundamental chemistry of small inorganic molecules and more established organic species. For example, the diagonal relationship between a methine fragment (C-H) and phosphorous has led to the latter being nicknamed a "carbon-copy". This has resulted in extensive chemistry aimed at developing phosphorus-containing analogues of organic molecules such as phospha-alkenes (RP=PR) and -alkynes (PCR), amongst many other examples. However, an isolobal relationship does not imply that phosphorus-containing congeners of specific organic molecules can be readily synthesized. In fact, the synthesis of relatively simple molecules where a C-H unit, or even an isoelectronic element such as nitrogen, has been replaced by a phosphorus atom still represents a significant technical and intellectual challenge. In this regard synthetic inorganic chemistry lags far behind organic synthesis.As a case in point, while urea was first synthetically isolated in 1829, it was not until late 2013 that our research group succeeded in the isolation of a phosphorus analogue, phosphinecarboxamide. Considering the importance of urea as a chemical feedstock, we propose to utilize this heavier analogue (and other related species) for the synthesis of novel molecules and solids. This is a completely new approach to organophosphorus compounds which, while inherently risky, has the potential to generate fascinating new species that are related to those derived from urea, but that have fundamentally different chemical and physical properties. Current methods for the synthesis of phosphorus-containing chemicals (employed, for example, in pharmaceuticals and specialty chemicals such as photo-initiators) require the use of phosphorus (III) chloride as a feedstock. While such processes currently represent the industrial state-of-the-art, the use of alternative non-toxic precursors remains a highly desirable objective. Alternative strategies to organophosphorus compounds based on the chemical activation of white phosphorus are possible (and well-documented in the literature), however such transformations are often marred by low selectivities or require multiple subsequent manipulations to be competitive with industrial processes. Moreover, white phosphorus is itself highly pyrophoric and dangerous to manipulate. The risks associated with these precursors make the identification of novel phosphorus-atom feedstocks highly desirable.We propose to develop the chemistry of a new class of phosphorus-containing small molecules that are accessible using red phosphorus, a non-pyrophoric allotrope of the element. Ultimately, this will allow us to reduce the safety risks typically encountered when manipulating conventional precursors for the synthesis of specialty chemicals. Building on recent breakthroughs in our laboratory, we will explore the chemistry of the 2-phosphaethynolate anion and phosphinecarboxamide, two novel phosphorus-containing analogues of otherwise ubiquitous chemicals (the cyanate ion and urea, respectively). Our ultimate goal is to access novel molecular, supramolecular and polymeric species with potential applications in catalysis, chemical sensing and materials chemistry. This proposal represents an entirely novel approach to the development of phosphorus-containing molecules and solids of enormous potential societal and economic impact.