Aromatic Polycarboxylate Research Articles

Structural Diversities of a Series of Cd(II) Coordination Complexes Based on a Flexible Tripodal N-donor Ligand

Three Cd(II) coordination complexes with unique structures and topologies, namely, {[Cd(tttmb)(Hbtc)]·5H2O}n (1), {[Cd(tttmb)(m-phda)(H2O)]·2H2O}n (2), and {[Cd(tttmb)(o-cpla)]·(CH3CN)·(H2O)1.5}n (3), have been successfully synthesized under hydro(solvo)thermally condition based on a flexible tripodal N-contained ligand 1,3,5-tris(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (tttmb) and aromatic polycarboxylate acids (H3btc = 1,2,4-benzenetricarboxylic acid, m-H2phda = 1,3-phenylenediacetic acid and o-H2cpla = Homophthalic acid). Complexes 1–3 were characterized by elemental analysis, IR spectroscopy, X-ray single-crystal diffraction and thermogravimetric analyses. 1 crystallize in the orthorhombic chiral space group P212121 and feature 3D coordination networks. 2 reveals a 2D ladder-like structure with (4,4) topology containing alternating Cd(II)/m-phda2− left- and right-handed helical motifs. 3 exhibits a 3D net with (63)(66)(7·82) topology. The structural and dimensional diversity of these complexes not only indicates that the flexible ligand tttmb exhibits strong coordination ability and diverse coordination modes, but also shows that aromatic polycarboxylates play important roles in constructing the frameworks of complexes. Moreover, the different photoluminescence behaviors of 1–3 have been studied in the solid state.

Luminescent Zinc(II) Coordination Polymers of Bis(pyridin-4-yl)benzothiadiazole and Aromatic Polycarboxylates for Highly Selective Detection of Fe(III) and High-Valent Oxyanions

The hydro(solvo)thermal reactions of Zn(NO3)2·6H2O, bis(pyridin-4-yl)benzothiadiazole (BTD-bpy), and benzene-1,3,5-tricarboxylic acid (H3btc) or naphthalene-1,4-dicarboxylic acid (1,4-H2ndc) yielde...

Two Ag(I)-Containing Supramolecular Coordination Polymers Constructed from the Multidentate N-donor Ligand 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(3-pyridyl)-1,2,4-triazole Based on Hydrogen-Bonding and π–π Interactions: Syntheses, Crystal Structures, Optical Band Gaps and Luminescent Properties

Two Ag(I)-based coordination polymers, namely [Ag2(3,3′-tmbpt)(o-Hbdc)2]·H2O (1) and [Ag8(3,3′-tmbpt)4(1,2,4-Hbtc)4(H2O)] (2) (3,3′-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(3-pyridyl)-1,2,4-triazole, o-H2bdc = 1,2-benzenedicarboxylic acid and 1,2,4-H3btc = 1,2,4-benzenetricarboxylic acid), have been synthesized. Single-crystal X-ray diffraction analyses, elemental analyses, infrared spectra, powder X-ray diffraction analyses and thermogravimetric analyses have been carried out to characterize the structures of 1 and 2. Compound 1 shows a (3,4)-connected 2D layered structure with a Schlafli symbol of (42·6)(42·63·8). The intermolecular O–H···O hydrogen-bonding interactions extend the 2D layer into a 3D supramolecular architecture. Compound 2 exhibits a (3,3)-connected double-layered structure with a Schlafli symbol of (4·8·10)2(82·10)2. The intermolecular C–H···O hydrogen-bonding interactions link the double-layers to form a 3D supramolecular architecture. Moreover, there are intramolecular and intermolecular π–π interactions in 1 and 2, which stabilize the whole 3D supramolecular architectures. The band gaps of 1 and 2 are 3.19 and 3.09 eV, respectively, indicating the potential of 1 and 2 as semiconductive materials with wide band gaps. Moreover, 1 and 2 emit intense blue-green light, which may be potential photoactive materials. Two Ag(I)-based 3D supramolecular coordination polymers constructed from a multidentate N-donor ligand and two aromatic polycarboxylate anions via hydrogen-bonding and π–π interactions have been synthesized and characterized. The band gaps and photoluminescent properties of the compounds have been studied.

Interplay between oxygen doping and ultra-microporosity improves the CO2/N2 separation performance of carbons derived from aromatic polycarboxylates

Microporous carbons were prepared starting from a series of benzene polycarboxylic acids following two strategies: (i) activation- and template-free pyrolysis and (ii) ion-exchange pyrolysis. The proposed synthetic strategies are facile approaches to produce highly microporous carbons that avoid the use of large amounts of corrosive and expensive chemical activators or templates. By varying the number of carboxylic acid groups, the charge balancing species and the degree of deprotonation of the precursors, microporous carbons with diverse morphologies, textural properties and oxygen contents were obtained and their CO2 and N2 sorption properties were assessed. The abundant micropores made the materials suitable for CO2 adsorption at low pressure and ambient temperature, achieving CO2 uptake as high as 4.4 mmol g−1 at 25 °C and 1 bar, competitive with those reported for porous carbons produced using large excess of alkali metal based activating agents. It was found that high performance, in terms of CO2 uptake and CO2/N2 selectivity, was linked to the simultaneous presence of large ultra-micropore volume and high oxygen content in the sorbents. This suggests that the interplay of ultra-microporosity and oxygen doping matters more than the two features taken singularly in determining the CO2/N2 separation properties of porous carbons at low pressure.

Syntheses, Crystal Structures, Characterization, Optical Band Gaps and Photoluminescence of Two Zn(II) Coordination Polymers

Two novel coordination polymers based on Zn(II) ions, 1-((1H-1,2,4-triazol-1-yl)methyl)-3-(4-pyridyl)-5-(3-pyridyl)-1,2,4-triazole (3,4′-tmbpt), and two aromatic polycarboxylate anions, namely [Zn(3,4′-tmbpt)(m-bdc)(H2O)]·H2O (1) and [Zn2(3,4′-tmbpt)(btc)(OH)] (2) (m-H2bdc = 1,3-benzenedicarboxylic acid and H3btc = 1,3,5-benzenetricarboxylic acid), have been synthesized. The structures of 1 and 2 have been characterized by single-crystal X-ray diffraction analyses, elemental analyses, infrared spectra, powder X-ray diffraction analyses and thermogravimetric analyses. Compound 1 shows a 2D layered structure, which is extended by the hydrogen bonding interactions to form a 3D supramolecular architecture. Compound 2 exhibits a 3D twofold interpenetrating framework with a Schlafli symbol of (63)(69·8). Diffuse reflection spectra of 1 and 2 indicate that the band gaps of 1 and 2 are 3.42 and 3.63 eV, respectively. The results indicate that compounds 1 and 2 may be potential semiconductive materials with wide band gaps. Moreover, 1 and 2 display intense blue-green emission and appear to be potential photoactive materials. Two new coordination polymers based on a multidentate N-donor ligand, Zn(II) ions, and two aromatic polycarboxylate anions have been synthesized and characterized. The optical band gaps and photoluminescent spectra of the compounds have been investigated.

Au-nanoparticle loaded nickel-copper bimetallic MOF: An excellent catalyst for chemical degradation of Rhodamine B

Synthesis, characterization and catalytic performance of Au-nanoparticle (NP) functionalized Nickel-Copper bimetallic three-dimensional MOF is presented. A three dimensional bimetallic MOF involving aromatic polycarboxylate ligands viz. benzene 1,4-dicarboxylate and benzene 1,3,5-tricarboxylate as linkers with Cu (II) and Ni (II) as metal nodes was synthesized through Solvothermal method. Structural and morphological studies of the as-synthesized material were carried out by FTIR, PXRD, SEM and TEM analysis. The elemental composition of the material was established by EDS mapping. Thermal stability of the as-prepared samples was tested by TGA analysis. The characterization details well establish the synthesis of first of its kind of bimetallic mixed metal–ligand MOF composed of nickel and copper metal ions trapped in an organic framework of bipodal and tripodal carboxylate based mixed ligands. The bimetallic MOF was successfully functionalized by Au NPs and was tested for its catalytic performance toward the chemical degradation of environmentally hazardous organic pollutant Rhodamine B. Compared to the pristine MOF, the Au doped MOF exhibited an exceptionally high catalytic activity (kapp = 13.74 × 10−2 min−1) and thermal stability, which can be attributed to the functional synergism prevailing between the Au nanoparticles and the three-dimensional bimetallic mixed ligand framework. The estimated kapp value for RhB degradation is significantly better than those reported for various state of the art nanocomposite catalysts reported in the recent past.

Synthesis and Properties of Two Fe(III) Coordination Polymers Based on 2-Amino-4-methylthiazole, 2-Mercaptobenzothiazole and Aromatic Polycarboxylate

Two of coordination polymers of the general formula [Fe(BDC)(AMTZ)Cl]·2H2O and [Fe(BDC)(MBT)Cl]·H2O, BDC = 1,4-benzenedicarboxylic acid, AMTZ = 2-amino-4-methyl-thiazole and MBT = 2-mercaptobenzothiazole, have been synthesized and characterized. Structure of both coordination polymers has been evaluated on the basis of elemental analysis, thermal, FT-IR, UV-vis spectra and the charges been carried by the atoms, caused a dipole moment of 2.4346 debye and total energy -382 × 103 Kcal mol-1. Biological activity of the two synthesized complexes was tested against some fungal and bacterial strains

Effects of two benzenedicarboxylic acids on the construction of CdII coordination polymers incorporating a flexible N-donor ligand.

Compared with the monomorphic type of ligand, combining mixed ligands in one coordination polymer offers greater tunability of the structural framework. Employment of N-heterocyclic ligands and aromatic polycarboxylates is an effective approach for the construction of metal-organic frameworks (MOFs). Two new coordination polymers incorporating both 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) and benzenedicarboxylic acid isomers, namely, catena-poly[[[di-μ-chlorido-bis[(2-carboxybenzoato-κ2O1,O1')cadmium(II)]]-bis{μ-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole-κ2N:N'}] dihydrate], {[Cd(C8H5O4)Cl(C11H10N4)]·H2O}n, (I), and poly[[aqua(μ2-benzene-1,3-dicarboxylato-κ3O1,O1':O3){μ2-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole-κ2N:N'}cadmium(II)] dihydrate], {[Cd(C8H4O4)(C11H10N4)(H2O)]·2H2O}n, (II), have been prepared and structurally characterized by single-crystal X-ray diffraction. In polymer (I), imb ligands bridge CdII ions, forming a one-dimensional chain, and 2-carboxybenzoate anions coordinate to the CdII ions in a terminal fashion. Polymer (II) exhibits a two-dimensional network structure in which imb ligands and the benzene-1,3-dicarboxylate anions join CdII ions co-operatively. This indicates that changing of the aromatic dicarboxylic acids can result in polymers with different compositions and architectures. Moreover, their IR spectra, PXRD (powder X-ray diffraction) patterns, thermogravimetric analyses and fluorescence properties were also investigated.

Synthesis, Crystal Structure, and Photoluminescent Properties of Two Porous Pillared-layer Metal-organic Frameworks Constructed by Benzene-1,3,5-tricarboxylic Acid and Bisimidazole Ligands

Two pillared layer metal organic frameworks, namely {[Co3(Btc)2(Bib)3(H2O)2] · 7H2O}n(I) and {[Cd2(Btc)(Bib)2(Fma)(H2O)] · H2O}n (II), where H3Btc is benzene-1,3,5-tricarboxylic acid, Fma is formate anion and Bib is 1,4-bis(1-imidazolyl)benzene, have been successfully synthesized by solvothermal method and structurally characterized by element analysis, IR spectroscopy, as well as single crystal X-ray diffractionand power X-ray diffraction (СIF files CCDC nos. 1829267 (I), 1829266 (II)). In the complexes I and II, the full deprotonated aromatic polycarboxylate take the same coordination mode to bridging four metal ions but result in different 2D network, which are further pillared by bib ligands to form 3D architectures with piont symbol of (42.64)2(42.67.8)2(64.82) and (42.63.8)(42.64)(42.67.8), respectively. The photoluminescent property of complex II is also reported.

A new stable porous Pr-organic framework constructed by multi-iodine-substituted aromatic polycarboxylates: Synthesis, characterization, and selective adsorption of dyes

abstractPoly[tris(dimethylformamide)(μ3-2,4,6-triiodol-1,3,5-benzene tricarboxylic acid)-praseodymium (III)] {Pr(TIBTC)(DMF)3}n (1) (H3TIBTC = 2,4,6-triiodo-1,3,5-benzene tricarboxylic acid) was synthesized by the reaction of Pr(NO3)3·6H2O and H3TIBTC at 85°C in a pyrex vial. 1 was characterized by elemental analysis, IR, UV–vis, TGA, PXRD, and atomic force microscopy analytical means. Each of the central Pr ions and the three carboxyl groups from the same ligand constitute a SBU, which is then joined by a carboxyl group to form a building block. In order to further explore the functional properties of 1, we used this compound for adsorption experiments. It is found that 1 can effectively adsorb anionic dyes in aqueous solutions. In particular, there is a good adsorption efficiency for coomassie brilliant blue R-250. Therefore, 1 shows good prospects for selective adsorption of anionic dyes from wastewater solution.

Cocrystals and Salts of 3,5-Bis(pyridinylmethylene)piperidin-4-one with Aromatic Poly-Carboxylates and Resorcinols: Influence of Stacking Interactions on Solid-State Luminescence Properties

Two bis-pyridyl-substituted α,β-unsaturated ketones were shown to form complexes with carboxylic acids and resorcinol derivatives. The neutral acid–acid homosynthon was observed in only one complex out of the five acid-bis-pyridyl containing complexes studied here, while the –COO−⋯HOOC– synthon was found to be dominant as it was observed in four complexes. The carboxylates self-assembled to form discrete dimeric, anionic, 1D chains and also exhibited mixed ionic hydrogen bonds. On the other hand, resorcinol derivatives displayed O–H⋯N hydrogen bonding to form tetrameric aggregates of bis-pyridyl ketone molecules and respective co-formers, while 3,5-dihydroxy benzoic acid (DHBA) molecules formed 1D chains by clipping two molecules of ketones with three DHBA molecules. Such clipping by the resorcinol derivatives promoted continuous π–π stacking interactions. Consequently, these materials emitted at higher wavelengths compared with the parent bis-pyridyl-substituted α,β-unsaturated ketones.

Synthesis and characterization of two 3D supramolecular cadmium(II) coordination polymers based on aromatic polycarboxylate and semi-rigidity bis(imidazole) ligands

Two new Cd(II) supramolecular coordination polymers (CPs) formulated as [Cd(L1)(DCTP)]n (1) and {[Cd(L2)(HBTC)(H2O)]·H2O}n (2) [H2DCTP = 2,5-dichloroterephthalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid, L1 = 1,3-bis(2-methylbenzimidazol-1-ylmethyl)benzene and L2 = 1,2-bis(imidazol-1-ylmethyl)benzene] were hydrothermally synthesized. Both CPs exhibit 2D (4,4) layered structures and further extend into 3D supramolecular frameworks by π–π stacking interactions for CP 1, OH⋯O classic hydrogen bonding interactions for CP 2, respectively. The luminescence and photocatalytic properties of CPs 1–2 for the degradation of methylene blue also presented.

Synthesis, crystal structure and topological analysis of a three-dimensional polymeric network based on zinc(II), potassium and 5-sulfobenzene-1,3-dicarboxylate (SIP).

Aromatic polycarboxylate linkers provide structural rigidity and strong interactions among the metal centre and the carboxylate O atoms. A new three-dimensional coordination polymer namely, catena-poly[potassium [tetraaqua(μ-5-sulfobenzene-1,3-dicarboxylato)zinc(II)]], {K[Zn(C8H3O7S)(H2O)4]}n or {K[Zn(SIP)(H2O)4]}n, where SIP is 5-sulfobenzene-1,3-dicarboxylate or 5-sulfoisophthalate, was obtained and characterized by elemental analysis and IR vibrational spectroscopy, and the single-crystal structure was determined by X-ray diffraction analysis. The compound crystallizes in the monoclinic space group P21/n with Z = 4. Topological analysis revealed that K-O interactions form a two-dimensional network, which is uninodal 4-connected and can be described with a point symbol (44.62), and this plane network is classified as sql/Shubnikov. The layers are connected by Zn2+ ions coordinated to the SIP linker, forming a three-dimensional network. This net is a trinodal (3,5,6)-connected system with point symbol (3.44.52.62.73.83).(3.44.52.62.7).(3.72).

Effect of three aromatic polycarboxylates on the structural diversities and properties of three new cadmium(II) coordination compounds

Three new cadmium(II) coordination compounds $$[\hbox {Cd}_{2} (\hbox {L})_{2} (\hbox {btec}) (\hbox {H}_{2} \hbox {O})_{2}] \cdot \hbox {3H}_{2} \hbox {O}$$ (1), [Cd(HL)(btb)] (2) and $$[\hbox {Cd}(\hbox {L})(\hbox {pda})] \cdot \hbox {2H}_{2} \hbox {O}$$ (3) were prepared by hydrothermal reactions of cadmium(II) chloride with ligands L ( $$\hbox {L} = \hbox {N}$$ , $$\hbox {N}^{\prime }$$ -bis(3-pyridyl)octandiamide) in the presence of different aromatic polycarboxylates ( $$\hbox {H}_{4} \hbox {btec} = \hbox {1,2,4,5-benzenetetracarboxylic acid}$$ , $$\hbox {H}_{3} \hbox {btb} = \hbox {1,3,5-tri(4-carboxylphenyl)benzene}$$ , $$\hbox {H}_{2} \hbox {pda} = \hbox {1,4-phenylenediacetic acid}$$ ). The structures of compounds 1–3 have been determined by X-ray single crystal diffraction analyses and further characterized by infrared spectroscopy (IR), powder X-ray diffraction (PXRD) and thermogravimetric (TG) analyses. Compound 1 displays a 3D metal-organic framework with (4,4,4)-connected $$\{6^{2}.8^{4}\} \{6^{3}.8^{3}\} \{6^{4}.8^{2}\}$$ topology constructed from 2D $$[\hbox {Cd}_{2} (\hbox {btec})]_{\mathrm{n}}$$ layers and $$\mu _{2}$$ -bridging L ligands. Compound 2 is a 3D (3,3)-connected $$\{10^{3}\}$$ topological network based on the 3D $$[\hbox {Cd(btb)}]_{\mathrm{n}}^{\mathrm{n}-}$$ framework and the protonated monodentate HL ligand. Compound 3 shows a 2D layer with (3,5)-connected $$(4^{2} \cdot 6^{7} \cdot 8)(4^{2} \cdot 6)$$ topological structure, which are further linked by hydrogen bonding interactions to form a 3D supramolecular network. The influences of three aromatic polycarboxylates on the structures of title compounds are investigated. Further, the fluorescent properties of three cadmium(II) compounds and their fluorescent sensing properties towards small solvent molecules and metal cations have been studied. Three new Cd(II) coordination compounds based on the flexible bis(pyridyl)-bis(amide) ligand and three different polycarboxylates have been hydrothermally synthesized. The polycarboxylates with diverse carboxyl groups and various structures play an important role in constructing three Cd(II) compounds. The thermal stabilities, fluorescent and fluorescence sensing properties of the three Cd(II) compounds towards small solvent molecules and metal cations have been reported.

Syntheses, structures and characterization of isomorphous CoII and NiII coordination polymers based on 2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole and benzene-1,4-dicarboxylate.

Careful choice of the organic ligands is one of the most important parameters in the rational design and synthesis of coordination polymers. Aromatic polycarboxylates have been widely used in the preparation of metal-organic polymers since they can utilize various coordination modes to form diverse structures and can act as hydrogen-bond acceptors and donors in the assembly of supramolecular structures. Nitrogen-heterocyclic organic compounds have also been used extensively as ligands for the construction of polymers with interesting structures. In the polymers catena-poly[[[diaquabis{2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole-κN3}cobalt(II)]-μ2-benzene-1,4-dicarboxylato-κ2O1:O4] dihydrate], {[Co(C8H4O4)(C12H11N4)2(H2O)2]·2H2O}n, (I), and catena-poly[[[diaquabis{2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole-κN3}nickel(II)]-μ2-benzene-1,4-dicarboxylato-κ2O1:O4] dihydrate], {[Ni(C8H4O4)(C12H11N4)2(H2O)2]·2H2O}n, (II), the CoII or NiII ion lies on an inversion centre and exhibits a slightly distorted octahedral coordination geometry, coordinated by two N atoms from two imidazole rings and four O atoms from two monodentate carboxylate groups and two water molecules. The dicarboxylate ligands bridge metal ions forming a polymeric chain. The 2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole ligands coordinate to the CoII or NiII centres in monodentate modes through an imidazole N atom and are pendant on opposite sides of the main chain. The two structures are isomorphous. In the crystal, the one-dimensional chains are further connected through O-H...O, O-H...N and N-H...O hydrogen bonds, leading to a three-dimensional supramolecular architecture. In addition, the IR spectroscopic properties, PXRD patterns, thermogravimetric behaviours and fluorescence properties of both polymers have been investigated.

Two pairs of Zn(ii) coordination polymer enantiomers based on chiral aromatic polycarboxylate ligands: synthesis, crystal structures and properties

Two pairs of Zn-based chiral coordination polymers were synthesized under hydrothermal conditions, exhibiting medium second-harmonic generation (SHG) activities and luminescent behavior.

Self-assembly, structures and properties of three new Ni(II) coordination polymers derived from two different bis-pyridyl-bis-amide ligands and two aromatic polycarboxylates

Three new Ni(II) coordination polymers exhibiting different 1D and 2D framework structures have been hydrothermally synthesized: [Ni(L 1)(1,3-BDC)(H 2O) 3] ⋅H 2O (1), [Ni(L 1)(1,3,5-HBTC)(H 2O) 3] (2), [Ni 3(L 2)3(1,3,5-BTC) 2(H 2O) 8] ⋅12H 2O (3) [L 1= N,N ′-bis(pyridin-3-yl)cyclohexane-1,4-dicarboxamide, L 2= N,N ′-bis(3-pyridyl)octandiamide, 1,3-H 2BDC = 1,3-benzenedicarboxylic acid, 1,3,5-H 3BTC = 1,3,5-benzenetricarboxylic acid]. X-ray single crystal diffraction analyses revealed that polymer 1 is a 2D interlaced layer based on the 1D [Ni(L 1)(1,3-BDC)(H 2O) 3] meso-helical chains. Polymer 2 is a 1D wave-shaped chain derived from the 1D [Ni(L 1)] n chain and monodentate coordinated 1,3,5-HBTC anions. Polymer 3 possesses an interesting 2D layer containing the trinuclear [Ni 3(1,3,5-BTC) 2] substructural unit and 1D zigzag [Ni(L 2)] n chain, representing a 3,4-connected {6 ⋅8 2} 2 {62⋅82⋅10⋅12} topology. Finally, the adjacent 1D chains or the 2D layers are connected through hydrogen bonding interactions to construct 3D supramolecular networks. Further, the thermal stability, solid state fluorescent property and photocatalytic activity of 1–3 have been investigated. Three new Ni(II) coordination polymers have been hydrothermally synthesized by self-assembly of two bis-pyridyl-bis-amide ligands (L1, L2) and two aromatic polycarboxylates (1,3-H2BDC, 1,3,5-H3BTC). The thermal stability, fluorescent properties and the photocatalytic activities of polymers 1–3 have been studied.

Series of Hydrated Heterometallic Uranyl-Cobalt(II) Coordination Polymers with Aromatic Polycarboxylate Ligands: Formation of U═O-Co Bonding upon Dehydration Process.

Five new heterometallic UO22+-Co2+ coordination polymers have been obtained by hydrothermal reactions of uranyl nitrate and metallic cobalt with aromatic polycarboxylic acids. Single-crystal X-ray diffraction reveals the formation of four 3D frameworks with the mellitate (noted mel) ligand and one 2D network with the isophthalate (noted iso) ligand. The compounds [(UO2(H2O))2Co(H2O)4(mel)]·4H2O (1), [UO2Co(H2O)4(H2mel)]·2H2O (2), and [(UO2(H2O))2Co(H2O)4(mel)] (4) consist of 3D frameworks built up from the connection of mellitate ligands and mononuclear metallic centers. These three compounds exhibit two types of geometry for the uranyl cation: pentagonal bipyramidal environment for 1 and 4, and hexagonal bipyramidal environment for 2. Using the mellitate ligand, the uranyl dinuclear unit is isolated in the compound [(UO2)2(OH)2(Co(H2O)4)2(mel)]·2H2O (3). Due to their 2D framework and the presence of uncoordinated cobalt(II) cations, the compound [(UO2)(iso)3][Co(H2O)6]·3(H2O) (5) is drastically different than the previous one. The thermal behavior of compounds 1, 2, and 3 has been studied by thermogravimetric analysis, X-ray thermodiffraction, and in situ infrared. By heating, the dehydration of compounds 1 and 2 promotes two structural transitions (1 → 1' and 2 → 2'). The crystal structures of [(UO2(H2O))2Co(H2O)2(mel)] (1') and [(UO2)Co(H2mel)] (2') were determined by single-crystal X-ray diffraction; each of them presents a heterometallic interaction between uranyl bond and the Co(II) center. Due to the rarely reported coordination environment for the cobalt center in compound 2' (square pyramidal configuration), the magnetic properties and EPR characterizations of the compounds 2 and 2' were also investigated.

Four Flexible Bis(Thiabendazole)-Based Cd(II) Coordination Polymers with Various Aromatic Carboxylates: Syntheses, Structures and Properties

Four Cd(II) coordination polymers (CPs) including [Cd(btbb)0.5(L1)]n (1), [Cd(btbb)(L2)·(H2O)1.5]n (2), [Cd(btbb)(L3)]n (3), and [Cd(btbb)(HL4)]n (4) (btbb = 1,4-bis(thiabendazole)butane, H2L1 = 5-hydroxyisophthalic acid, H2L2 = 4,4′-biphenyldicarboxylic acid, H2L3 = tetrabromoterephthalic acid, H3L4 = 5-nitro-1,2,3-benzenetricarboxylic acid) were prepared under hydrothermal conditions based on flexible bis(thiabendazole) ligand and different co-carboxylates. Their structures have been determined by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra, X-ray powder diffraction, and thermogravimetric analyses. CP 1 exhibits a 3D 2-nodal (3,4)-connected framework with the 3,4T10 topology. CP 2 and 3 feature typical hcb layer structure, and 3 is further combined into a 3D supramolecular architecture through C–H⋯O hydrogen bonds. CP 4 possesses an infinite chain and further extended into 2D supramolecular network by O–H⋯O hydrogen-bonding interactions. The effects of the aromatic polycarboxylate co-ligands on the CPs framework have been discussed and the catalytic activities of CPs 1–4 for degradation of methyl orange in Fenton-like process are also investigated.

Mixed ligand two dimensional Cd(ii)/Ni(ii) metal organic frameworks containing dicarboxylate and tripodal N-donor ligands: Cd(ii) MOF is an efficient luminescent sensor for detection of picric acid in aqueous media.

Two dimensional metal organic frameworks (MOFs) [Cd(5-BrIP)(TIB)]n () and [Ni2(5-BrIP)2(TIB)2]n (), involving the aromatic polycarboxylate ligand 5-bromo isophthalic acid (H2BrIP), flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)benzene (TIB) and Cd(ii)/Ni(ii) metal nodes have been synthesized by different methods. These compounds were characterized by various analytical methods, and variable temperature X-ray diffraction data showed thermal stability of both MOFs up to 350 °C. Phase purity as well as water stability of the MOFs were established by powder X-ray diffraction, and the structural diversity of the compounds were investigated by single-crystal X-ray diffraction. Both the MOFs are mixed ligand 2D nets, and the topology of the network can be described as a binodal 3,5-c connected net with 3,5L2 topology having the point symbol {4(2)·6(7)·8}{4(2)·6}. Sensing of picric acid [2,4,6-trinitrophenol, TNP] by luminescence quenching among a large range of nitroanalytes in aqueous phase by the Cd(ii) luminescent MOF (LMOF) were been investigated. Structural studies on 1 : 1 co-crystals () of TIB and TNP were carried out. The selective and sensitive fluorescence quenching response of towards electron-deficient TNP over other nitro analytes in aqueous phase was demonstrated by fluorescence quenching titration. Concomitant occurrence of electron transfer/energy transfer processes and electrostatic interaction favours the selective sensing of TNP. A Cd(ii) LMOF ()-coated paper strip that we developed demonstrated fast and selective response to TNP, by the complete quenching of the blue fluorescence upon excitation of the paper strip at 365 nm radiation in its presence.