Pyrrophens: Pyrrole-Based Hexadentate Ligands Tailor-Made for Uranyl (UO<sub>2</sub><sup>2+</sup>) Coordination and Molecular Recognition
作者:Jacob T. Mayhugh、Julie E. Niklas、Madeleine G. Forbes、John D. Gorden、Anne E. V. Gorden
DOI:10.1021/acs.inorgchem.0c00439
日期:2020.7.20
Derivatives of a novel pyrrole-containing Schiff base ligand system (called “pyrrophen”) are presented which feature substituted phenylene linkers (R1 = R2 = H (H2L1); R1 = R2 = CH3 (H2L2)) and a binding pocket modeled after macrocyclic species. These ligands bind neutral CH3OH in the solid state through pyrrolic hydrogen-bonding. The interaction of the uranyl cation (UO22+) and H2L1–2 yields planar hexagonal bipyramdial uranyl complexes, while the Cu2+ and Zn2+ complexes were found to self-assemble as dinuclear helicate complexes (M2L2) with H2L1 under identical conditions. The favorable binding of UO22+ over Zn2+ provides insight into the molecular recognition of uranyl over other metal species. Structural features of these complexes are examined with special attention to features of the UO22+ coordination environment which distinguish them from other related salophen and porphyrinoid complexes.
介绍了一种新颖的含吡咯的 Schiff 碱配体系统(称为“pyrrophen”),其特征是有取代的苯基连接器(R1 = R2 = H (H2L1); R1 = R2 = CH3 (H2L2)),并且其结合口袋是基于大环物种进行建模的。这些配体通过吡咯氢键在固态下与中性 CH3OH 结合。铀盐阳离子(UO22+)与 H2L1–2 的相互作用产生了平面六角双锥铀复合物,而 Cu2+ 和 Zn2+ 复合物在相同条件下被发现自组装为二核螺旋配合物 (M2L2) 与 H2L1 结合。UO22+ 相对于 Zn2+ 的优良结合提供了对铀盐相较于其他金属物种的分子识别的见解。对这些复合物的结构特征进行了研究,特别关注 UO22+ 配位环境的特征,这些特征使它们与其他相关的 salophen 和 porphyrinoid 复合物有所区别。