Synthesis, structural analysis, and supramolecular assembly of a series of in situ generated uranyl–peroxide complexes with functionalized 2,2′-bipyridine and varied carboxylic acid ligands†
The crystal structures of eight new binuclear peroxo-bridged uranyl (UO22+) complexes containing chelating N-donating ligands (2,2′-bipyridine [BPY] and 4,4′-dibromo-2,2′-bipyridine [BrBPY]) and various O-donating ligands (m-halobenzoic acid (where halo = fluoro, chloro, or iodo), p-toluic acid, 2-thiophenecarboxylic acid, acetic acid, benzoic acid, and p-(bromomethyl)-benzoic acid [BrMeBA]) are reported. Single crystal and powder X-ray diffraction analyses have been used to characterize these materials and provide insight into local coordination environments and supramolecular assembly, including π-stacking and halogen-based interactions. The bridging-peroxide ligands were generated in situ via photoexcitation of the uranyl cation induced by incident sunlight. Notably, five of the eight complexes presented have linear U–O2–U dihedral angles and the non-covalent interactions (NCIs) observed in all complexes suggest a direct influence on this structural feature.