화학공학소재연구정보센터
Inorganic Chemistry, Vol.59, No.14, 9560-9568, 2020
Pyrrophens: Pyrrole-Based Hexadentate Ligands Tailor-Made for Uranyl (UO22+) Coordination and Molecular Recognition
Derivatives of a novel pyrrole-containing Schiff base ligand system (called "pyrrophen") are presented which feature substituted phenylene linkers (R-1 = R-2 = H (H2L1); R-1 = R-2 = 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 Znprovides 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.