Bipyridine-Directed Syntheses of Uranyl Compounds Containing Semirigid Dicarboxylate Linkers: Diversity and Consistency in Uranyl Speciation

Bipyridine organic bases are beneficial to the synthesis of novel uranyl–organic hybrid materials, but the relationship between their molecular structures and specific roles as structure-directing agents, especially for the semirigid dicarboxylate systems, is still unclear. Here we demonstrate how the bipyridine ligands direct the coordination assembly of uranyl–organic compounds with a semirigid dicarboxylate linker, 4,4′-dicarboxybiphenyl sulfone (H2dbsf), by utilizing a series of bipyridine ligands, 1,10-phenanthroline (phen), 2,2′-bipyridine (2,2′-bpy), 5,5′-dimethylbipyridine (5,5′-dmbpy), 4,4′-bipyridine (4,4′-bpy), or 1,3-di(4-pyridyl)propane (bpp). Under hydrothermal conditions, eight uranyl–organic coordination polymers (UCPs), four of which [[UO2(dbsf)(phen)] (1), [UO2(dbsf)(phen)]·H2O (1′), [U4O10(dbsf)3]2[H2bpp]2 (6), and [U4O10(dbsf)3]2[H2bpp] (6′)] were reported previously, were synthesized and divided into two types based on the chelate or template effect of these bipyridine ligands. 1, 1′,...