Oligomere Harnstoffe - Synthese, Konformation und Anionenbindung

低聚脲 - 合成、构象和阴离子结合

• 批准号: 5383648
• 负责人: Dr. Volker Böhmer
• 金额: --
• 依托单位: Fachbereich 09: Chemie, Pharmazie, Geographie und Geowissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2002
• 资助国家: 德国
• 起止时间: 2001-12-31 至 2008-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5383648?language=en
• 关键词: Oligomere; Harnstoffe; Synthese; Konformation; und

Urea functions (R-NH-CO-NH-R) are able to form two hydrogen bonds to the same acceptor and have been used as binding sites in various anion receptors of the podand type. If three urea functions are incorporated in a suitably sized macrocycle anions should be bound by six convergent R-NH···X hydrogen bonds as indicated schematically for nitrate. High binding energies are predicted on the basis of first MD simulations for trigonal planar anions such as Nitrate or Carbonate and especially for "tripodal" anions such as Sulfonate and Phosphonate. In the frame of this project various macrocylic triureas of this general type will be synthesised, since subtle changes of the size or shape of the spacer groups will most probably have drastic influences on the complexation behaviour. The design of these ligands will be based primarily on MD simulations, and secondly on reasonable modifications of these "lead structures". Additional substituents extending the outside of the macrocycle will achieve solubility either in apolar or aqueous solutions and/or create chromo- or fluorophoric properties. Binding constants for the range of interesting anions will be determined, using techniques like NMR-titration, UV-Vis spectrometry or conductimetry. Calorimetric measurements will complete the set of thermodynamic data for the complexation. The results thus obtained will be compared again with calculated values, to understand the complexation in detail and to check the validity of the theoretical/mathematical model. In selected cases we will also try to measure the complexation/decomplexation kinetics (dynamic NMR and stoppped-flow techniques). For comparison we will synthesise and study linear analogues (tri- to hexa-ureas), which should assume a helical conformation, eventually induced by the complexed anion(s). These studies might be extended finally to the construction of helical poly-ureas.

尿素功能（R-NH-CO-NH-R）能够与同一受体形成两个氢键，并已被用作豆荚型阴离子受体的结合位点。如果在一个合适大小的大环中加入三个尿素功能，阴离子应该由六个聚合的r - nh_···X氢键结合，如图所示。在首次原子动力学模拟的基础上，预测了硝酸盐或碳酸盐等三角形平面阴离子，特别是磺酸盐和膦酸盐等“三足”阴离子的高结合能。在这个项目的框架内，将合成这种一般类型的各种大环三元化合物，因为间隔基团的大小或形状的细微变化很可能对络合行为产生巨大的影响。这些配体的设计将主要基于MD模拟，其次是对这些“导联结构”的合理修改。延伸到大环外部的附加取代基将在极性或水溶液中实现溶解度和/或产生显色或亲氟性质。通过核磁共振滴定法、紫外-可见光谱法或电导法等技术，将确定感兴趣阴离子范围的结合常数。量热测量将完成络合的热力学数据集。这样得到的结果将再次与计算值进行比较，以详细了解络合并检查理论/数学模型的有效性。在选定的情况下，我们还将尝试测量络合/解合动力学（动态核磁共振和止流技术）。为了比较，我们将合成和研究线性类似物（三脲到六脲），它们应该具有螺旋构象，最终由络合阴离子诱导。这些研究最终可能扩展到螺旋型聚脲的构建。