Varying structure‐directing anions in uranyl ion complexes with Ni(2,2ʹ:6ʹ,2″‐terpyridine‐4ʹ‐carboxylate)2
Résumé
2,2ʹ:6ʹ,2″-Terpyridine-4ʹ-carboxylic acid (tpycH) reacts with uranyl cations under solvo-hydrothermal conditions to give [UO$_2$(tpyc)$_2$]⋅2H$_2$O ( 1 ), a monoperiodic polymer different from that previously reported. In the additional presence of Ni$^{II}$ cations, the Ni(tpyc)$_2$ “expanded ligand” is formed and the structure of its complexes with the uranyl cation depends on the additional anions present. [(UO$_2$)$_2$F$_4$(H$_2$O)$_2$Ni(tpyc)$_2$]⋅2H$_2$O ( 2 ) and [UO$_2$(mds)(H$_2$O)Ni(tpyc)$_2$] ( 3 ), where mds$^{2-}$ is methanedisulfonate, are monoperiodic polymers in which the fluoride anions are bridging and the mds$^{2–}$ anions chelating. [(UO$_2$)$_4$(NO$_3$)$_2$(H$_2$O)$_4$Ni$_5$(tpyc)$^{10}$](CF$_3$SO$_3$)$_4$ (NO$_3$)$_2$⋅7H$_2$O ( 4 ) crystallizes as a wide and nearly planar monoperiodic ribbon. [(UO$_2$)$_2$(NO$_3$)$_2$(chdc)Ni(tpyc)$_2$]⋅chdcH$_2$⋅2CH$_3$CN ( 5 ), where chdc$^{2–}$ is trans -1,4-cyclohexanedicarboxylate, is a monoperiodic chain including both bridging Ni(tpyc)$_2$ and chdc$^{2–}$ ligands, the chains being further assembled into layers through hydrogen bonding to bridging chdcH$_2$ molecules. Finally, [UO$_2$Ni$_2$(tpyc)$_4$](I$_3$)$_2$ ( 6 ) crystallizes as a diperiodic network with sql topology. These results point to the possibility of modulating the structure of cationic uranyl ion complexes with Ni(tpyc)$_2$ through addition of a wide range of bonding or non-bonding anions.
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