The comparison of fac and merruthenium(ii) trischelate complexes in anion binding
作者:Naomi C. A. Baker、Neil McGaughey、Nicholas C. Fletcher、Aleksey V. Chernikov、Peter N. Horton、Michael B. Hursthouse
DOI:10.1039/b816149f
日期:——
The synthesis of three new homoleptic trischelate ruthenium(II) complexes bearing new 2,2′-bipyridine ligands, 5,5′-dibenzylamido-2,2′-bipyridine (L1) and 5-benzylamido-2,2′-bipyridine (L2) has been achieved. In the case of [Ru(L2)3]2+, the mer and fac isomers have been separated. 1H NMR spectroscopic anion binding studies indicate that the two C3-symmetric pockets provided by [Ru(L1)3]2+ is conducive to receive a range of anions, although this is not readily reflected in the photophysical behaviour. The fac-isomer of [Ru(L2)3]2+ does appear to have an enhancement in the binding interactions over the mer form with dihydrogenphosphate salts, although the difference is much less marked with the spherical chloride ions. From X-ray crystallographic evidence, the ability to hold water in the “anion” binding cleft can inhibit the strength of the interactions with anions, giving rise to the observed selectivity for directional oxoanions such as dihydrogen phosphate.
我们合成了三种新的同色三螯合钌(II)配合物,它们带有新的 2,2′-联吡啶配体,即 5,5′-二苄基氨基-2,2′-联吡啶(L1)和 5-苄基氨基-2,2′-联吡啶(L2)。对于 [Ru(L2)3]2+,mer 和 fac 异构体已经分离。1H NMR 光谱阴离子结合研究表明,[Ru(L1)3]2+ 提供的两个 C3 对称口袋有利于接受一系列阴离子,尽管这并不容易反映在光物理行为中。[Ru(L2)3]2+的面异构体与磷酸二氢盐的结合相互作用似乎比mer形式的要强,尽管与球形氯离子的差异要小得多。从 X 射线晶体学证据来看,在 "阴离子 "结合裂隙中保持水的能力会抑制与阴离子相互作用的强度,从而导致观察到的对磷酸二氢盐等定向氧阴离子的选择性。