The three zwitterionic di- and tricarboxylate ligands 1,1′-[(2,3,5,6-tetramethylbenzene-1,4-diyl)­bis­(methylene)]­bis­(pyridin-1-ium-4-carboxylate) (pL1), 1,1′-[(2,3,5,6-tetramethylbenzene-1,4-diyl)­bis­(methylene)]­bis­(pyridin-1-ium-3-carboxylate) (mL1), and 1,1′,1″-[(2,4,6-trimethylbenzene-1,3,5-triyl)­tris­(methylene)]­tris­(pyridin-1-ium-4-carboxylate) (L2) have been used as ligands to synthesize a series of 15 uranyl ion complexes involving various anionic coligands, in most cases polycarboxylates. [(UO2)2(pL1)2(cbtc)­(H2O)2]·10H2O (1, cbtc4– = cis,trans,cis-1,2,3,4-cyclobutanetetracarboxylate) is a discrete, dinuclear ring-shaped complex with a central cbtc4– pillar. While [UO2(pL1)­(NO3)2] (2), [UO2(pL1)­(OAc)2] (3), and [UO2(pL1)­(HCOO)2] (4) are simple chains, [(UO2)2(mL1)­(1,3-pda)2] (5, 1,3-pda2– = 1,3-phenylenediacetate) is a daisy chain and [UO2(pL1)­(pdda)]3·10H2O (6, pdda2– = 1,2-phenylenedioxydiacetate) is a double-stranded, ribbon-like chain. Both [UO2(pL1)­(pht)]·5H2O (7, pht2– = phthalate) and [(UO2)3(mL1)­(pht)2(OH)2] (8) crystallize as diperiodic networks with the sql topology, the latter involving hydroxo-bridged trinuclear nodes. [(UO2)2(pL1)­(c/t-1,3-chdc)2] (9, c/t-1,3-chdc2– = cis/trans-1,3-cyclohexanedicarboxylate) and [UO2(pL1)­(t-1,4-chdc)]·1.5H2O (10, t-1,4-chdc2– = trans-1,4-cyclohexanedicarboxylate) are also diperiodic, with the V2O5 and sql topologies, respectively. Both [(UO2)2(mL1)­(c/t-1,4-chdc)2] (11) and [(UO2)2(pL1)­(1,2-pda)2] (12, 1,2-pda2– = 1,2-phenylenediacetate) crystallize as diperiodic networks with hcb topology, and they display threefold parallel interpenetration. [HL2]­[(UO2)3(L2)­(adc)3]Br (13, adc2– = 1,3-adamantanedicarboxylate) contains a very corrugated hcb network with two different kinds of cells, and the uncoordinated HL2+ molecule associates with the coordinated L2 to form a capsule containing the bromide anion. [(UO2)2(pL1)­(kpim)2] (14, kpim2– = 4-ketopimelate) is a three-periodic framework with pL1 molecules pillaring fes diperiodic subunits, whereas [(UO2)2(L2)2(t-1,4-chdc)]­(NO3)1.7Br0.3·6H2O (15), the only cationic complex in the series, is a triperiodic framework with dmc topology and t-1,4-chdc2– anions pillaring fes diperiodic subunits. Solid-state emission spectra and photoluminescence quantum yields are reported for all complexes.

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The 2,5‐, 2,6‐, and 3,5‐pyridinedicarboxylic (2,5‐, 2,6‐ and 3,5‐pydcH2), and 2,3‐pyrazinedicarboxylic (2,3‐pyzdcH2) acids have been used to synthesize six uranyl ion complexes including various counterions under solvo‐hydrothermal conditions. While [NH4]2[UO2(2,6‐pydc)2]·3H2O (1) is a discrete, mononuclear species, [UO2(2,6‐pydc)2Cu(R,S‐Me6cyclam)] (2) crystallizes as a monoperiodic coordination polymer through axial bonding of copper(II) to carboxylate donors. [PPh3Me][UO2(OH)(2,5‐pydc)]·H2O (3) and [Ni(R,S‐Me6cyclam)][UO2(OH)(2,5‐pydc)]2·2H2O (4) contain di‐hydroxo‐bridged dinuclear uranyl subunits assembled into homometallic, monoperiodic polymers. [(UO2)2(3,5‐pydc)2(HCOO)2Ni(R,S‐Me6cyclam)] (5) crystallizes as a heterometallic diperiodic network with the V2O5 topology, and [PPh4][UO2(OH)(2,3‐pyzdc)] (6) is a diperiodic species with sql topology. All complexes have well‐resolved uranyl emission spectra in the solid state, and three of them have photoluminescence quantum yields among the highest reported for uranyl carboxylate complexes, 44 % for 1, 71 % for 3, and 36 % for 6.

N,N,N′,N′-Tetramethylethane-1,2-diammonioacetate (L1) and N,N,N′,N′-tetramethylpropane-1,3-diammonioacetate (L2) are two flexible zwitterionic dicarboxylates which have been used as ligands for the uranyl ion, 12 complexes having been obtained from their coupling to diverse anions, mostly anionic polycarboxylates, or oxo, hydroxo and chlorido donors. The protonated zwitterion is a simple counterion in [H2L1]­[UO2(2,6-pydc)2] (1), where 2,6-pydc2– is 2,6-pyridinedicarboxylate, but it is deprotonated and coordinated in all the other complexes. [(UO2)2(L2)­(2,4-pydcH)4] (2), where 2,4-pydc2– is 2,4-pyridinedicarboxylate, is a discrete, binuclear complex due to the terminal nature of the partially deprotonated anionic ligands. [(UO2)2(L1)­(ipht)2]·4H2O (3) and [(UO2)2(L1)­(pda)2] (4), where ipht2– and pda2– are isophthalate and 1,4-phenylenediacetate, are monoperiodic coordination polymers in which central L1 bridges connect two lateral strands. Oxalate anions (ox2–) generated in situ give [(UO2)2(L1)­(ox)2] (5) a diperiodic network with the hcb topology. [(UO2)2(L2)­(ipht)2]·H2O (6) differs from 3 in being a diperiodic network with the V2O5 topological type. [(UO2)2(L1)­(2,5-pydc)2]·4H2O (7), where 2,5-pydc2– is 2,5-pyridinedicarboxylate, is a hcb network with a square-wave profile, while [(UO2)2(L1)­(dnhpa)2] (8), where dnhpa2– is 3,5-dinitro-2-hydroxyphenoxyacetate, formed in situ from 1,2-phenylenedioxydiacetic acid, has the same topology but a strongly corrugated shape leading to interdigitation of layers. (2R,3R,4S,5S)-Tetrahydrofurantetracarboxylic acid (thftcH4) is only partially deprotonated in [(UO2)3(L1)­(thftcH)2(H2O)] (9), which crystallizes as a diperiodic polymer with the fes topology. [(UO2)2Cl2(L1)3]­[(UO2Cl3)2(L1)] (10) is an ionic compound in which discrete, binuclear anions cross the cells of the cationic hcb network. 2,5-Thiophenediacetate (tdc2–) is peculiar in promoting self-sorting of the ligands in the ionic complex [(UO2)5(L1)7(tdc)­(H2O)]­[(UO2)2(tdc)3]4·CH3CN·12H2O (11), which is the first example of heterointerpenetration in uranyl chemistry, involving a triperiodic, cationic framework and diperiodic, anionic hcb networks. Finally, [(UO2)7(O)3(OH)4.3Cl2.7(L2)2]­Cl·7H2O (12) crystallizes as a 2-fold interpenetrated, triperiodic framework in which chlorouranate undulating monoperiodic subunits are bridged by the L2 ligands. Complexes 1, 2, 3, and 7 are emissive with photoluminescence quantum yields in the range of 8–24%, and their solid-state emission spectra show the usual dependence on number and nature of donor atoms.

Wheel-type heptanuclear heterometallic clusters display metal ion dependent ferromagnetic properties and express single molecule magnet behavior based on the magnetic anisotropy.