Mayhugh JT, Niklas JE, Forbes MG, Gorden JD, Gorden AEV. Pyrrophens: Pyrrole-Based Hexadentate Ligands Tailor-Made for Uranyl (UO
22+) Coordination and Molecular Recognition.
Inorg Chem 2020;
59:9560-9568. [PMID:
32590898 DOI:
10.1021/acs.inorgchem.0c00439]
[Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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.
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