Cavity Formation in Uranyl Ion Complexes with Kemp’s Tricarboxylate: Grooved Diperiodic Nets and Polynuclear Cages

Kemp’s triacid (cis,cis-1,3,5-trimethylcyclohexane-1,3,5-tricarboxylic acid, H3kta) was reacted with uranyl nitrate under solvo-hydrothermal conditions in the presence of diverse counterions or additional metal cations to give eight zero- diperiodic complexes. All coordination polymers series, [PPh3Me][UO2(kta)]·0.5H2O (1), [PPh4][UO2(kta)] (2), [C(NH2)3][UO2(kta)] (3), [Cd(bipy)3][UO2(kta)]2 (4), and [Zn(phen)3][UO2(kta)]2·2H2O (5) (bipy = 2,2?-bipyridine, phen 1,10-phenanthroline) crystallize as networks hcb topology, ligand being chair conformation three carboxylate groups equatorial, except 3, which axial/diequatorial boat is present. Various degrees corrugation different arrangements neighboring layers are observed depending on counterion, complexes 4 5, particular, displaying cavities containing bulky cations. [Co(en)3]2[(UO2)2(kta)(Hkta)2]2·2NMP·10H2O (6) (en 1,2-ethanediamine; NMP N-methyl-2-pyrrolidone) contains a metallatricyclic, tetranuclear anionic species, two clefts held by extensive hydrogen bonding, ligands both triaxial conformations. [(UO2)3Pb(kta)2(Hkta)(H2O)]2·1.5THF (7) (THF tetrahydrofuran) [(UO2)2Pb2(kta)2(Hkta)(NMP)]2 (8) heterometallic cage compounds only convergent, form ligand, have same topology spite U/Pb ratio. These compared previous ones also involving anions, roles formation cavities, either cage-like species grooves networks, discussed.