Two novel uranyl complexes of a semi-rigid aromatic tetracarboxylic acid supported by an organic base as an auxiliary ligand or a templating agent: an experimental and theoretical exploration

Exploring New Assembly Modes of Uranyl Terephthalate: Templated Syntheses and Structural Regulation of a Series of Rare 2D → 3D Polycatenated Frameworks

“…The inactive terminal oxo groups of uranyl often prevent axial bonding interactions, resulting in any further coordination occurring in the equatorial plane. As a result, uranyl-organic coordination polymers usually prefer to form onedimensional (1D) chains, 10,[15][16][17] or two-dimensional (2D) sheets, [18][19][20][21][22][23][24] rather than threedimensional (3D) frameworks that require structural connectivity in the third axial dimension. [25][26][27][28][29][30][31][32] 2D networks or 3D frameworks with large cavities or pores can readily achieve a high degree of self-assembly by an entangled mode in the solid state, and thus afford a variety of intriguing topological structures as well as fascinating properties.…”

Probing the Influence of N‐Donor Capping Ligands on Supramolecular Assembly in Molecular Uranyl Materials

“…Polypyridyl chelating N‐donors feature relatively large binding affinities for f‐element ions (specifically the [UO 2 ] 2+ cation) 36. Some of the ligands of this class, such as 1,10‐phenanthroline (phen) and 2,2′:6′,2″‐terpyridine (terpy) (and its derivatives), have been explored as “capping” ligands in the synthesis uranyl coordination polymers,18,37–40 molecular uranyl materials,41–44 and lanthanide hybrid materials 45–47. Herein we are using these ligands explicitly as tools for crystal engineering by the chelation of part of the equatorial uranyl coordination sphere, thus promoting further assembly by halogen or hydrogen bonding, π–π stacking interactions, or a combination thereof.…”

Complexes of Uranyl Ions with Aromatic Di‐ and Tetracarboxylates Involving [Ni(bipy)n]2+ (n = 2, 3) Counterions

“…The complex formed by hfdp 4– with uranyl ions alone crystallizes also as a thick 2D network, but in this case the uranyl cations are located on the faces and the ligands span the whole inner space, while the sheets in 4 can be seen as built of two thin layers connected to one another by the bridging bidentate carboxylate groups. It is notable that thick, bilayer arrangements were also found in uranyl ion complexes of the related ligand benzophenone‐3,3′,4,4′‐tetracarboxylate,, suggesting a particular propensity of these V‐shaped ligands to form such architectures. In this case also, parallel‐displaced π‐stacking interactions involving both ligands may be present, [centroid ··· centroid distances 3.836(5)–4.434(5) Å, dihedral angles 0–14.1(4)°], but examination of the HS shows that they are not greater than dispersion.…”

“…Concerning the syntheses, the most unexpected result here is that of complex 3 , prepared from 1,4,5,8‐naphthalenetetracarboxylic acid (H 4 ntc), but containing instead just its doubly deprotonated 1,8‐monoanhydride (ntcma 2– ). Anhydrides are commonly hydrolyzed under hydrothermal conditions,, but the six‐membered ring formed here enhances the stability of the anhydride unit. Another index of this stability is that recrystallization of H 4 ntc from dimethyl sulfoxide gives crystals of the monoanhydride .…”

“…No uranyl complex with either of the two naphthalene derivatives has been reported (but nine structures with the positional isomer 1,4‐naphthalenedicarboxylate are in the CSD, ). Uranyl complexation by 4,4′‐(1,1,1,3,3,3‐hexafluoroisopropylidene)diphthalic acid has been the subject of only one study, three complexes with the geometrically related benzophenone‐3,3′,4,4′‐tetracarboxylic acid having also been reported , …”