Lanthanide coordination polymers with dicarboxylate-like ligands : crystal structures of polymeric neodymium(III) and erbium(III) complexes with flexible double betaines

Flexible Aliphatic Diammonioacetates as Zwitterionic Ligands in UO22+ Complexes: Diverse Topologies and Interpenetrated Structures

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-pydc^2- 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-pydc^2- 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 ipht^2- and pda^2- are isophthalate and 1,4-phenylenediacetate, are monoperiodic coordination polymers in which central L1 bridges connect two lateral strands. Oxalate anions (ox^2-) 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-pydc^2- is 2,5-pyridinedicarboxylate, is a hcb network with a square-wave profile, while [(UO₂)₂(L1)(dnhpa)₂] (8), where dnhpa^2- 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 (tdc^2-) 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)_4.3Cl_2.7(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.

Crystal structure of N 1,N 3-bis(2-hydroxyethyl)-N 1, N 1,N 3,N 3-tetramethylpropane-1,3-diaminium dibromide, C11H28Br2N2O2

C11H28Br2N2O2, triclinic, P1̄ (no. 2), a = 12.0519(11) Å, b = 12.6670(12) Å, c = 12.9161(12) Å, α = 117.088(3)°, β = 92.459(1)°, γ = 108.199(2))°, V = 1627.2(3) Å3, Z = 4, R gt(F) = 0.0645, wR ref(F 2) = 0.1632, T = 298(2) K.

Synthesis and structure of dimeric anthracene-9-carboxylato bridged dinuclear erbium(III) complex, [Er(2)(9-AC)(6)(DMF)(2)(H(2)O)(2)]

We study the influence of the bulky aromatic rings, e.g. anthracence-9-carboxylic acid (9-ACA) with a large conjugated pi-system on the structure and spectroscopic properties of [Er(2)(9-AC)(6)(DMF)(2)(H(2)O)(2)] complex where 9-AC=anthracence-9-carboxylato and DMF=N,N'-dimethylformamide. The complex has been prepared from the erbium chloride and 9-ACA in the mixture of H(2)O:DMF solution (4:1, v/v) followed by pH adjustment to 6. The complex is crystallized in a monoclinic system with space group P2(1)/n. The two Er(III) ions are double bridged by the deprotonated carboxyl groups of two 9-AC anions (O1 and O1A), forming an eight-coordination number. The chelating bidentate (O,O), chelating-bridging tridentate (O,O,O') and monodentate of 9-AC anions are observed in the dinuclear [Er(2)(9-AC)(6)(DMF)(2)(H(2)O)(2)] complex. The Er-Er distance is 4.015A in the dimeric unit. Intramolecular O-Hcdots, three dots, centeredO and C-Hcdots, three dots, centeredO hydrogen bonds as well as numerous of intermolecular C-Hcdots, three dots, centeredpi interactions between the anthracene rings by edge-to-face interactions linked the dinuclear dimeric units into two-dimensional supramolecular network in a propeller-arrangement. Electronic absorption spectra of the Er(III) complex and its salt were measured. The emission spectrum of the complex is composed of a broad band due to the emission of intraligand pi*-->pi transition from the 9-AC anions and a shoulder peak originating from the 4f-4f emission transition of the Er(III) ions. The complex has a high thermal stability which can be attributed to the effectively increase the rigidity of the 9-AC anions.