Aliphatic Dicarboxylate Ligands Research Articles

Two Cd(II) MOFs of Flexible Aliphatic Dicarboxylate Ligands and 1,4-Bis[(2-methyl-1H-imidazol-1-yl)-methyl]benzene: Synthesis, Crystal Structures and Selective Sensing of Fe3+

Two Cd(II) MOFs of Flexible Aliphatic Dicarboxylate Ligands and 1,4-Bis[(2-methyl-1H-imidazol-1-yl)-methyl]benzene: Synthesis, Crystal Structures and Selective Sensing of Fe3+

Structural and spectroscopic studies of spontaneously formed crystalline Eu(iii)-aliphatic dicarboxylates at room temperature.

Complexation of actinides and lanthanides with carboxylic organic ligands is a critical issue affecting radionuclide migration from deep geological disposal systems of spent nuclear fuel. A series of Eu(iii)–aliphatic dicarboxylate compounds, as chemical analogs of radioactive Am(iii) species, Eu2(Ox)3(H2O)6, Eu2(Mal)3(H2O)6, and Eu2(Suc)3(H2O)2, were synthesized and characterized using X-ray crystallography and time-resolved laser fluorescence spectroscopy to examine the ligand-dependent binding modes and the corresponding changes in spectroscopic properties. Powder X-ray crystallography results confirmed that all of the compounds presented a crystalline polymer structure with a trigonal prism square-face tricapped polyhedron geometry centered on Eu(iii) in a nine-coordinate environment involving nine oxygen atoms. This study captures the transition of the coordination modes of aliphatic dicarboxylate ligands from side-on to end-on binding as the carbon chain length increases. This transition is illustrated in malonate bindings involving a combination of side-on and end-on modes. Strongly enhanced luminescence, especially for the hypersensitive peak, indicates a low site symmetry in the formation of solid compounds. The number of remaining bound water molecules was estimated from the resultant increased luminescence lifetimes, which were in good agreement with crystal structures. The excitation–emission matrix spectra of these crystalline polymers suggest that Ox ligands promote the sensitized luminescence of Eu(iii), especially in the UV region. In the case of Mal and Suc ligands, charge transfer occurs in the opposite direction from Eu(iii) to the ligands under UV excitation, resulting in weaker luminescence.

Plumbing the uncertainties of solvothermal synthesis involving uranyl ion carboxylate complexes

Uranyl ion complexes with long-chain, saturated or unsaturated aliphatic dicarboxylate ligands illustrate how solvo-hydrothermal synthetic conditions sometimes result in the formation of species different from those hoped for.

CdII -Organic Frameworks Fabricated with a N-Rich Ligand and Flexible Dicarboxylates: Structural Diversity and Multi-Responsive Luminescent Sensing for Toxic Anions and Ethylenediamine.

Three metal-organic frameworks {[Cd(L)(glu)]⋅3 H2 O}∞ (1), {[Cd2 (L)2 (adi)2 ]⋅5 H2 O}∞ (2) and {[Cd(L)(sub)]⋅3 H2 O⋅DMA }∞ (3) (L=pyridine-3,5-bis(5-azabenzimidazole), H2 glu=glutaric acid, H2 adi=adipic acid and H2 sub=suberic acid) were obtained under solvothermal conditions. Complex 1 shows a 2D (4,4) network constructing of Cd2 -glu and Cd-L chains. Complex 2 presents a 2-fold interpenetrating 3D framework with pcu topology. Complex 3 is a 3D framework with cds topology. Three complexes with versatile structures were obtained by changing aliphatic dicarboxylate ligands with different lengths based on a N-rich ligand. Moreover, the fluorescence measurements indicate that complex 1 is a good multifunctional chemosensor for the detection of Cr2 O7 2- and MnO4 - anions by fluorescence quenching effect, and ethylenediamine by fluorescence enhancement effect, with detection limits of 1.196 ppm, 0.551 ppm and 64.572 ppm, respectively. Both complexes 2 and 3 can selectively sense Cr2 O7 2- anion with detection limits of 1.126 ppm for 2 and 0.831 ppm for 3 by a fluorescence quenching effect.

Odd‐Even Effect on Luminescence Properties of Europium Aliphatic Dicarboxylate Complexes

The odd-even effect in luminescent [Eu2 (L)3 (H2 O)x ]⋅y(H2 O) complexes with aliphatic dicarboxylate ligands (L: OXA, MAL, SUC, GLU, ADP, PIM, SUB, AZL, SEB, UND, and DOD, where x=2-6 and y=0-4), prepared by the precipitation method, was observed for the first time in lanthanide compounds. The final dehydration temperatures of the Eu3+ complexes show a zigzag pattern as a function of the carbon chain length of the dicarboxylate ligands, leading to the so-called odd-even effect. The FTIR data confirm the ligand-metal coordination via the mixed mode of bridge-chelate coordination, except for the Eu3+ -oxalate complex. XRD results indicate that the highly crystalline materials belong to the monoclinic system. The odd-even effect on the 4 f-4 f luminescence intensity parameters (Ω2 and Ω4 ) is explained by using an extension of the dynamic coupling mechanism, herein named the ghost-atom model. In this method, the long-range polarizabilities ( ) were simulated by a ghost atom located at the middle of each ligand chain. The values of were estimated using the localized molecular orbital approach. The emission intrinsic quantum yield ( ) of the Eu3+ complexes also presented an the odd-even effect, successfully explained in terms of the zigzag behavior shown by the Ω2 and Ω4 intensity parameters. Luminescence quenching due to water molecules in the first coordination sphere is also discussed and rationalized.

A one-dimensional copper(II) coordination polymer incorporating succinate and N,N-diethylethylenediamine ligands: crystallographic analysis, vibrational and surface features, and DFT analysis.

Transition metal atoms can be bridged by aliphatic dicarboxylate ligands to produce chains, layers and frameworks. The reaction of copper sulfate with succinic acid (H2succ) and N,N-diethylethylenediamine (deed) in basic solution produces the complex catena-poly[[[(N,N-diethylethylenediamine-κ2N,N')copper(II)]-μ-succinato-κ2O1:O4] tetrahydrate], {[Cu(C4H4O4)(C6H16N2)]·4H2O}n or {[Cu(succ)(deed)]·4H2O}n. Each carboxylate group of the succinate ligand coordinates to a CuII atom in a monodentate fashion, giving rise to a square-planar coordination environment. The succinate ligands bridge the CuII centres to form one-dimensional polymeric chains. Hydrogen bonds between the ligands and water molecules link these chains into sheets that lie in the ab plane. Density functional theory (DFT) calculations were used to support the experimental data. From these calculations, a good linear correlation was observed between the experimental and theoretically predicted structural and spectroscopic parameters (R2 ∼ 0.97).

Tuning different kinds of entangled metal-organic frameworks by modifying the spacer group of aliphatic dicarboxylate ligands and the reactant ratio.

Taking advantage of the conformational flexibility of the bpp ligand and aliphatic dicarboxylic acids, six interesting entangled coordination polymers, {[Cd(fum)(bpp)(H2O)]·(H2O)}n (), {[Cd(fum)(bpp)2]·(H2O)5}n (), {[Cd2(suc)1.5(bpp)2(NO3)(H2O)2]·6H2O}n (), {[Cd(suc)(bpp)2]·(H2O)1.5}n (), {[Cd2(glu)2(bpp)3]·10H2O}n (), and {Cd(adp)(bpp)(H2O)}n () have been prepared and structurally characterized (bpp = 1,3-bi(4-pyridyl)propane, fum = fumaric, suc = succinate, glu = glutaric, adp = adipic). Compounds and are comprised of undulated 2D 4(4)-sql networks. In the structure of compound , two identical undulated layers are parallelly interpenetrated with each other to give a 2D → 2D interpenetrating framework. For , the dangling arms projected from 2D layers are intercalated into the neighboring sheets, producing a 2D → 3D polythreading framework. Compound shows a rare example of a 2D self-penetrating framework with a (3,4)-connected (4(2)·6(3)·8)(4(2)·6) topology. Compound presents an unusual 2D self-threading network with a novel 4-connected {4(2)·6(3)·8} topology. Compound displays a 3D self-penetrating system based on a 2D → 3D parallel polycatenation array. Compound exhibits an unprecedented 3D self-penetrating structure having both 1D + 1D → 1D polycatenation and 3D + 3D → 3D interpenetration characteristics. A comparison of these six compounds demonstrates that both the different spacer lengths of the aliphatic dicarboxylates and reactant ratios appear to play a significant role in the assembly of entangled frameworks. In addition, thermal stabilities and photoluminescence properties of have been examined in the solid state at room temperature.

Three CdII complexes based on 2-(1H-imidazol-1-methyl)-1H-benzimidazole and homologous aliphatic dicarboxylates

Three cadmium complexes incorporating both aliphatic α,ω-dicarboxylate and 2-(1H-imidazol-1-methyl)-1H-benzimidazole (imb) have been prepared and structurally characterized. [Cd2Cl2(suc)(imb)2(H2O)]n (1) manifests 2D layered structure built from the linkage of tetranuclear [Cd4Cl4(suc)2(H2O)2] units through two kinds of imb ligands. {[Cd(glu)(imb)]·H2O}n (2) contains ladderlike [Cd(glu)]n chains which are bridged by imb ligands to form the 2D layers. {[Cd2Cl2(adi)(imb)2]·2H2O}n (3) also displays 2D network in which dinuclear units [Cd2Cl2] were linked by imb ligands to form double-stranded chains and these chains were further linked by adi2− ligands. Results indicate that aliphatic dicarboxylate ligands play an important role in governing the formation of final frameworks. Additionally, IR spectra, PXRD patterns, TG analyses and fluorescent properties of certain complexes have been determined.

Syntheses, crystal structures and magnetic properties of two 2D copper–nitroxide coordination polymers bridged by flexible aliphatic dicarboxylate ligands

Two novel two-dimensional copper–nitroxide coordination polymers of formula [Cu2(NIT3Py)2(glu)2]n (1) and {[Cu2(NIT3Py)2(adip)2]·CH3OH·0.5H2O}n (2) (NIT3Py=2-(3′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, H2glu=glutaric acid and H2adip=adipic acid), have been synthesized and characterized structurally as well as magnetically. The crystal structures of both polymers contain the paddle-wheel binuclear Cu(II) units axially coordinated by NIT3Py ligands which are bridged by the flexible glutarate or adipate anions into the corrugated 2D sheets. Interestingly, complex 1 displays a 2D helical layer structure rarely found in metal–nitroxide systems. The magnetic measurements show the strong antiferromagnetic interactions in the binuclear Cu(II) units and weak antiferromagnetic interactions between copper ions and nitroxides.

Aliphatic Dicarboxylate Ligands Assemble Weakly Coupled Molecular Pairs of [MnIII]2 Units

AbstractSeven new tetranuclear MnIII compounds have been obtained by assembling two dinuclear units, [{Mn(L)(NN)}2(μ‐O)]4+, with aliphatic dicarboxylate ligands COO(CH2)nCOO2–: succinato (n = 2, C42–), glutarato (n = 3, C52–) and adipato (n = 4, C62–), and NN = 2,2′‐bipyridine (bpy) or 1,10‐phenanthroline (phen). The general formula for these compounds is [{Mn(L)(NN)}4(μ‐Cm)2(μ‐O)2]X4 [X = ClO4, NN = bpy and Cm = C4 (1), C5 (2) and C6 (3); X = ClO4, NN = phen and Cm = C4 (4), C5 (5) and C6 (6); X = NO3, NN = bpy and Cm = C5 (7)]. Compounds 1, 2 and 4 were characterized by X‐ray diffraction, which confirmed the assembly of two dinuclear entities. The magnetic properties of the seven compounds were studied and the results indicate that the main interaction takes place within the dinuclear units. Compound 4 shows a dominant ferromagnetic coupling with J = 4.0 cm–1, while the rest of compounds display antiferromagnetic couplings with J values of –2.8 (1), –1.9 (2), –3.3 (3), –0.3 (5), –0.4 (6) and –9.3 cm–1 (7), which are all in agreement with magneto‐structural correlations. In the case of compound 4, a weak but significant antiferromagnetic coupling of the S = 4 [MnIII]2 subunits with an interaction constant of –0.9 cm–1 was observed.

Self-assembled coordination polymers of V-shaped bis(pyridyl)thiadiazole dependent upon the spacer length and flexibility of aliphatic dicarboxylate ligands

An investigation into 2,5-bis(4-pyridyl)-1,3,4-thiadiazole (bpt) and cupric or cadmium complexes with a large variety of aliphatic α,ω-dicarboxylic acids HOOC-X-COOH (X = (CH2)n, n = 0–4 corresponding to oxalic acid (H2ox), malonic acid (H2mal), succinic acid (H2suc), glutaric acid (H2glu) and adipic acid (H2adi); CHCH, maleic acid (H2male) and fumaric acid (H2fum)) is performed. Ten novel metal–organic architectures, [Cu2(bpt)(ox)2]n·2.92nH2O (1), [Cu(bpt)(mal)(H2O)]n·2nH2O (2), [Cu(bpt)(glu)]n (3), [Cu(bpt)(adi)]n (4), [Cu2(bpt)2(fum)2]n·3nH2O (5), [Cd(bpt)(mal)(H2O)]n (6), [Cd(bpt)(suc)]n (7), [Cd(bpt)(glu)]n·nH2O (8), [Cd2(bpt)2(male)2]n·2nH2O (9), and [Cd(bpt)(fum)(H2O)]n·nH2O (10) were successfully synthesized through varying the organic acid linkers. The molecule 1 is a 3D pillared-layer framework with the open channels encapsulating infinite 1D water chains. Complex 2 shows the contorted 2D layer, which is extended to a 2-fold interpenetrated 3D supramolecular net by antidromic R24(8) hydrogen-bonding pattern. Compound 3 is a grid-like layer motif with the terminal bpt ligands as pendants. The MOFs 4 and 5 present two-fold interpenetrating primitive cubic (α-Po) coordination networks. Interestingly, discrete tetrameric water clusters exist in the micropores of the MOF 5. For the cadmium complex 6, six-coordinated metal centers link malonate and bpt to form interdigitated layers through edge-to-face π–π stacking interactions. Coordination polymer 7 can be considered as six-connected self-penetrated topological 3D network, in which the right- and left-handed helices are alternately arranged into a wavy Cd/succinate layer. Flexible glutarate with cadmium atoms produces a 1D ribbon, and is further linked by bpt ligands to produce the 2D double-layered motif 8. Incorporating with rigid butenedioic acid, the reaction of seven-coordinated cadmium and bpt leads to two distinct 2D (4,4) layered frameworks 9 and 10, with a one-dimensional Cd–O chain observed in the former framework. A systematic structural comparison of these ten complexes indicates that the final polymeric structures could be tuned through the introduction of the different backbone length and flexibility of the aliphatic dicarboxylates. In addition, host–guest chemistry of MOFs 1 and 5, and the luminescent properties of cadmium compounds were discussed.

Diverse dimensionalities and structures in copper coordination polymers incorporating substituted aliphatic dicarboxylate ligands and 4,4′-bipyridine

Abstract Hydrothermal synthesis has afforded a series of divalent copper coordination polymers with substituted glutarate ligands and the rigid rod tether 4,4′-bipyridine (bpy): {[Cu(Hdmg)2(bpy)]·H2O}n (1, dmg = 3,3-dimethylglutarate), {[Cu2(dmg)(bpy)2](ClO4)]n (2), [Cu2(emg)2(bpy)]n (3, emg = 3-ethyl, 3-methylglutarate) and [Cu2(cda)2(bpy)]n (4, cda = 1,1-cyclopentanediacetate). All materials were characterized by single-crystal X-ray diffraction. Compound 1 manifests μ2-oxygen bridged [Cu2(Hdmg)4] “X”-patterns connected into a ribbon motif by bpy linkers. On the other hand, 2 possesses mixed-valence [CuICuIICuIICuI] tetrameric clusters bridged by dmg ligands and pillared into an 8-connected body-centered cubic (bcu) cationic lattice by bpy linkers. Compounds 3 and 4 are structurally very similar, displaying chain motifs with {Cu2(CO2)4} paddlewheels connected by dicarboxylates, in turn conjoined into (4,4)-grid coordination polymer layers by bpy tethers. Variable temperature magnetic data indicate the presence of very strong antiferromagnetic coupling within the {Cu2(CO2)4} paddlewheels in the latter two complexes, with g = 2.30(2) and J = −352(3) cm−1 for 3 and g = 2.35(2) and J = −352(5) cm−1 for 4. Significant structural contrasts are evident when compared to previously reported divalent copper/4,4′-bipyridine coordination polymers with unsubstituted or 2-methyl substituted glutarate ligands.

Cu(II) coordination polymers incorporating 3-aminopyridine and flexible aliphatic dicarboxylate ligands: Synthesis, structure and magnetic properties

The synthesis, structural chemistry and magnetic properties of a series of new Cu(II) polymers with α,ω-dicarboxylic acids (sebacic (H 2seb), suberic (H 2sub), succinic (H 2suc) and adipic (H 2adip)) and 3-aminopyridine (3-apy) are described: [Cu(Hsub) 2(3-apy) 2·2CH 3OH] n ( 1); [Cu(Hseb) 2(3-apy) 2·4CH 3OH] n ( 2); [Cu(Hsuc) 2(3-apy) 2] n ( 3); [Cu(adip)(3-apy) 2] n · n(H 2adip) ( 4). All four compounds feature a bis-monodentate bridging mode of the coordinated dicarboxylate moiety. Compounds 1 and 2 exhibit linear chains, whereas compound 3 shows two-dimensional structure. The 3-apy ligand acts as terminal ligand in 1– 3. Compound 4 contains a doubly deprotonated adipate (adip 2−) that connects Cu centers into linear chains. Additionally, 3-apy acts as a bridge in 4, resulting in the formation of parallel two-dimensional layers distant enough to host neutral molecules of adipic acid. Magnetic susceptibility measurements of compounds 1 and 3 show Curie law behavior indicating that the S = 1/2 Cu(II) spin carriers are magnetically well isolated by the dicarboxylate ligands.

Ionothermal synthesis of inorganic–organic hybrid materials containing perfluorinated aliphatic dicarboxylate ligands

Two new hybrid inorganic-organic frameworks containing perfluorinated dicarboxylate ligands have been synthesized ionothermally from a mixture of 1-ethyl-3-methylimidazolium bromide (emim-Br), and triflimide (emim-Tf(2)N). The cobalt(ii) tetrafluorosuccinate, [emim](2)[Co(H(2)O)(2)(O(2)CCF(2)CF(2)CO(2))(2)] (), is a two-dimensional coordination polymer containing anionic framework layers separated by emim cations. When hexafluoroglutaric acid is used in similar reactions, [emim](2)[Co(3)(O(2)CCF(2)CF(2)CF(2)CO(2))(4)(H(2)O)(4)] () forms. Like , this phase contains anionic layers of cobalt and the fluorinated carboxylate separated by emim cations. These new phases represent the first examples of ionothermally synthesized materials using perfluorinated aliphatic carboxylates.

One- and two-dimensional divalent copper coordination polymers based on kinked organodiimine and long flexible aliphatic dicarboxylate ligands

Hydrothermal synthesis under acidic conditions has afforded a pair of divalent copper coordination polymers containing the kinked dipodal tethering organodiimine 4,4′-dipyridylamine (dpa) and flexible long-chain aliphatic dicarboxylate ligands. The new materials were characterized by single crystal X-ray structure determination, infrared spectroscopy, and thermogravimetric analysis. [CuCl(suberate) 0.5(dpa)] ( 1) manifests 1-D ladder-like motifs aggregated into 3-D through hydrogen bonding and copper-mediated supramolecular interactions. Extension of the aliphatic chain within the dicarboxylate ligand by one methylene unit resulted in {[Cu(azelate)(dpa)(H 2O)] · 3H 2O} ( 2), a (4,4) rhomboid grid 2-D coordination polymer encapsulating acyclic water molecule trimers.

Diverse Entangled Metal−Organic Framework Materials Incorporating Kinked Organodiimine and Flexible Aliphatic Dicarboxylate Ligands: Synthesis, Structure, Physical Properties, and Reversible Structural Reorganization

Hydrothermal synthesis has afforded a family of divalent metal adipate (adp) coordination polymers incorporating the kinked dipodal organodiimine 4,4'-dipyridylamine (dpa). As revealed by single-crystal X-ray diffraction, the structures of these materials are critically dependent on the metal coordination geometry, the carboxylate binding modes, and the conformations of the flexible adipate moieties. In all cases, hydrogen-bonding interactions imparted by the dpa tethers also play a structure-directing role. All materials were further characterized via infrared spectroscopy and elemental and thermogravimetric analysis. [Co(adp)(dpa)] (1) displays doubly interpenetrated three-dimensional (3-D) networks with a decorated alpha-Po-type (pcu) topology. In contrast, [Ni(adp)(dpa)(H2O)] (2) possesses a triply interpenetrated binodal cooperite-type (pts) framework, the highest level of interpenetration yet reported for this structure type. [Zn(adp)(dpa)].H2O (3) presents mutually inclined polycatenated 2-D graphitic layers consisting of neutral dimeric [Zn2(mu2-adp)2] kernels conjoined by dipodal dpa ligands. Compound 1 exhibited weak antiferromagnetic coupling between its carboxylate-bridged Co atoms, following Curie-Weiss behavior with Theta=-3.3 K. Compound 3 manifested blue light emission under ultraviolet excitation, as well as a reversible structural reorganization upon dehydration/rehydration.