Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
Org Lett. 2017 Jan 20;19(2):324-327. doi: 10.1021/acs.orglett.6b03423. Epub 2017 Jan 11.
Toward the development of photoresponsive anion receptors, a stiff-stilbene photoswitch has been equipped with two urea anion-binding motifs. Photoinduced E/Z isomerization has been studied in detail by UV-vis and NMR spectroscopy. Titration experiments (H NMR) reveal strong binding of acetate and phosphate to the (Z)-isomer, in which the urea groups are closely together. Isomerization to the (E)-form separates the urea motifs, resulting in much weaker binding. Additionally, geometry optimizations by density functional theory (DFT) illustrate that oxo-anion binding to the (Z)-form involves four hydrogen bonds.
为了开发对光响应的阴离子受体，我们在刚性联苯光开关上装备了两个脲阴离子结合基序。通过紫外可见光谱和 NMR 光谱详细研究了光诱导的 E/Z 异构化。滴定实验（NMR）表明，（Z）-异构体对乙酸根和磷酸根具有很强的结合能力，其中脲基紧密相连。异构化为（E）-形式会分离脲基，导致结合能力大大减弱。此外，密度泛函理论（DFT）的几何优化表明，（Z）-形式的氧阴离子结合涉及四个氢键。
