State Key Laboratory for Oxo Synthesis & Selective Oxidation, Lanzhou Institute of Chemical Physics, CAS, Lanzhou 730000, China.
Inorg Chem. 2013 May 20;52(10):5851-60. doi: 10.1021/ic3028012. Epub 2013 May 7.
Two bisurea (L(1), L(2)) and one bisthiourea (L(3)) ligands were synthesized and their anion coordination behavior was studied. These ligands can readily form the tris chelates PO4(L)3 (1, 5, and 6) with phosphate ion (PO4(3-)) in the solid state, in which the anion is coordinated by six urea groups through 12 hydrogen bonds. Solution binding studies by (1)H NMR and UV-vis spectroscopy revealed different binding properties of the ligands toward phosphate ion. While the bis(p-nitrophenyl)-substituted bisurea L(1) retains the 3:1 (host to guest) binding ratio in solution, the diethyl derivative L(2) only forms 1:1 complex with phosphate ion. The more acidic thiourea L(3) undergoes deprotonation/decomposition in the presence of phosphate ion. Moreover, the sulfate complex (2) of L(1) and bicarbonate (3) and carbonate (4) complexes of L(2) have also been obtained, which show lower coordination numbers both in the solid state and in solution.
两种双脲（L(1)，L(2)）和一种双硫脲（L(3)）配体被合成，并研究了它们的阴离子配位行为。这些配体可以在固态中容易地与磷酸根离子（PO4(3-)）形成三螯合配合物PO4(L)3（1、5 和 6），其中阴离子通过 12 个氢键被六个脲基配位。通过（1）H NMR 和紫外可见光谱的溶液结合研究表明，配体对磷酸根离子具有不同的结合性质。虽然双（对硝基苯基）取代的双脲 L(1)在溶液中保持 3:1（主体对客体）的结合比例，但二乙酯衍生物 L(2)仅与磷酸根离子形成 1:1 配合物。更酸性的硫脲 L(3)在存在磷酸根离子时会发生去质子化/分解。此外，还获得了 L(1)的硫酸盐配合物（2）和 L(2)的碳酸氢盐（3）和碳酸盐（4）配合物，它们在固态和溶液中都显示出较低的配位数。
