The polymer of isocyanic acid has been referred to as cyamelide (cyamelid) by Liebig and Wöhler in some early studies, in which it was considered a mixture of chain polymers of isocyanic acid and cyanuric acid. Despite the knowledge of its fundamental structure, the chain polymeric compound has not been well characterized. We herein polymerized isocyanic acid and purified the resultant polymer to obtain a white powder. This powder was characterized by using IR, Raman, and UV spectroscopies; X-ray diffraction analysis; and band calculations. Analogous to the extended systems of urea, e.g., biuret, triuret, and higher oligomers, we refer to this polymer as polyuret. The structural chemistry of the polyuret was thoroughly explored with regard to possible cis / trans -isomerism. This polymer has flat bands at the frontier levels due to the nonbonding character of the urea moieties. We suggest that this compound should no longer be referred to as cyamelide or polyisocyanate to avoid confusion with the aforementioned uncharacterized mixture or with isocyanate-pendant polymers. A stable polymer of urea, polyuret, with nonbonding flat bands, was characterized by means of spectroscopic measurements and theoretical calculations. Polyuret takes a cis -form in the solid state with P 2 1 / c space group, in which adjacent main chains interact with each other through hydrogen bonds. DFT calculations show the presence of well-defined flat bands that form the highest occupied crystal orbitals, making polyuret a suitable candidate for prospective applications in designing for new types of magnetic materials.

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聚脲的结构方面和电子状态——构建具有非粘合平带的稳健扩展系统

Liebig 和Wöhler 在一些早期研究中将异氰酸聚合物称为cyamelide（cyamelid），其中它被认为是异氰酸和氰尿酸的链状聚合物的混合物。尽管知道其基本结构，但链状聚合物还没有得到很好的表征。我们在此聚合异氰酸并纯化所得聚合物以获得白色粉末。该粉末通过使用红外光谱、拉曼光谱和紫外光谱进行表征；X射线衍射分析；和波段计算。类似于尿素的扩展系统，例如缩二脲、三脲和更高级的低聚物，我们将这种聚合物称为聚脲。关于可能的顺/反异构现象，对聚氨酯的结构化学进行了彻底的探索。由于尿素部分的非键合特性，该聚合物在前沿水平具有平坦带。我们建议该化合物不应再称为 cyamelide 或多异氰酸酯，以避免与上述未表征的混合物或异氰酸酯侧链聚合物混淆。一种稳定的尿素聚合物，聚脲，具有非粘合平带，通过光谱测量和理论计算进行表征。聚脲在固态下呈顺式，具有 P 2 1 / c 空间群，其中相邻的主链通过氢键相互作用。DFT 计算表明存在定义明确的平坦带，形成最高占据的晶体轨道，使聚脲成为设计新型磁性材料的前瞻性应用的合适候选者。