Syntheses and Characterization of Six Coordination Polymers of Zinc(II) and Cobalt(II) with 1,3,5-Benzenetricarboxylate Anion and Bis(imidazole) Ligands

Seven new metal-organic frameworks assembled from semi-rigid polycarboxylate and auxiliary N-donor ligands: syntheses, structures and properties

Seven new metal-organic frameworks (MOFs), namely, [Zn₂(L¹)(H₂O)₃]_n (1), [Zn₂(L¹)(dib)(H₂O)₂]_n (2), {[Zn₂(L¹)(4,4'-bipy)(H₂O)₂]·H₂O}_n (3), [Cd₂(L¹)(1,10-phen)]_n (4), [Ni₂(HL¹)(4,4'-bipy)(μ₃-OH)(μ₂-H₂O)]_n (5), {[Co₄(L¹)(4,4'-bibp)₃]·(4,4'-bibp)₃}_n (6), and [Co₂(L²)(4,4'-bibp)₂(H₂O)]_n (7), where H₄L¹ and H₄L² are semi-rigid 3-(3,5-dicarboxylphenoxy)phthalic acid and 4-(3,5-dicarboxylphenoxy)phthalic acid, respectively, and 4,4'-bipy is 4,4'-bipyridine, dib is 1,4-bis(1H-imidazol-1-yl)benzene, 1,10-phen is 1,10-phenanthroline and 4,4'-bipb is 1,4-bis(pyridin-4-yl)benzene, have been prepared under solvothermal conditions with Zn^II, Cd^II, Co^II and Ni^II ions in the presence of auxiliary N-donor ligands. The crystal structures and photoluminescence and magnetic properties of these compounds have been investigated. Compound 1 displays a 3,4,6-connected two-dimensional (2D) topology with a Schläfli symbol of (4².5)₂(4³.5².7)(4⁵.5⁶.6³)₂, and the 2D structure was further assembled to form a three-dimensional (3D) framework by intermolecular O-H...O hydrogen bonds. Compound 2 features a novel 3,3,4-connected structure and the point symbol is (4.10²)(4.6.8⁴)(6².8). Compound 3 exhibits a 3,4,6-connected 3-nodal net having a 3,4,6 T53 type topology, with the point symbol (4.6²)₂(4².6⁴)₂(4².6⁸.8².10³). Compound 4 shows a 2D→3D supramolecular structure formed by π-π stacking interactions. Compound 5 possesses a 3D framework with a tfz-d net topology. Compounds 6 and 7 are constructed from the same auxiliary ligand and metal salt at the same temperature, but with different main ligands and exhibiting different topologies. Compound 6 presents a 3D 4,6-connected topological network with a Schläfli symbol of (3.4⁴.6)(3².4⁴.5⁶.6³), while compound 7 has a 3D topological network with a Schläfli symbol of (4¹².6¹⁶). Magnetic analyses indicate that compounds 5 and 7 show weak antiferromagnetic interactions.

Phosphatase-mimicking activity of a unique penta-nuclear zinc(ii) complex with a reduced Schiff base ligand: assessment of its ability to sense nitroaromatics

A penta-nuclear zinc(ii) complex has been synthesized and characterized. The complex has shown good phosphatase-mimicking activity, which has been evaluated spectrophotometrically. The complex also behaves as a sensor for the detection of nitroaromatics via turn-off fluorescence response.

Various types of isopolymolybdate-based metal–organic complexes formed in different conditions: synthesis, structures, luminescence, electrochemical, and photocatalytic performances

A series of isopolymolybdate-based complexes of different metals and ligands were prepared, which exhibited different luminescence behaviors, current sensing activities, and photocatalytic MB performances.

Joint Experimental and Computational Investigation of the Flexibility of a Diacetylene-Based Mixed-Linker MOF: Revealing the Existence of Two Low-Temperature Phase Transitions and the Presence of Colossal Positive and Giant Negative Thermal Expansions

Solvothermal reaction in N,N-dimethylformamide (DMF) between 1,6-bis(1-imidazolyl)-2,4-hexadiyne monohydrate (L1⋅H₂ O), isophthalic acid (H₂ L2), and Zn(NO₃ )₂ ⋅6 H₂ O gives the diacetylene-based mixed-ligand coordination polymer {[Zn(L1)(L2)](DMF)₂ }_n (UMON-44) in 38 % yield. Combination of DSC with variable-temperature single-crystal X-ray diffraction revealed the occurrence of two phase transitions spanning the ranges 129-144 K and 158-188 K. Furthermore, the three structurally similar phases of UMON-44 show giant negative and/or colossal positive thermal expansions. These unusual phenomena exist without any change in the contents of the unit cell. DFT calculations using the PBE+D3 dispersion scheme were able to distinguish between these polymorphs by accurately reproducing their salient structural features, although corrections in the size of the unit cell turned out to be necessary for the high-temperature phase to account for its large thermal expansion. In addition, the infrared spectra (vibration frequencies and peak intensities) of these theoretical models were calculated, allowing for univocal identification of the corresponding polymorphs. Last, the limits of our computational method were tested by calculating the phase transition temperatures and their associated enthalpies, and the derived figures compare favorably with the values determined experimentally.

A luminescent zinc(ii) coordination polymer with unusual (3,4,4)-coordinated self-catenated 3D network for selective detection of nitroaromatics and ferric and chromate ions: a versatile luminescent sensor

A zinc coordination polymer is a sensor for detection of TNP, Fe³⁺, Cr₂O₇²⁻ and CrO₄²⁻.

Crystal structures and investigation of the third-order nonlinear optical properties of four coordination polymers by using the Z-scan technique

Four coordination polymers with different structures are reported. They exhibit different third-order nonlinear optical activities.

Synthesis, crystal structure, and anti-breast cancer activity of a novel metal-porphyrinic complex [YK(TCPP)(OH)2·(solvents)x]

A novel heterometallic metal-porphyrinic framework (MPFs) built from Y and K ions as nods and meso-tetra(4-carboxyphenyl)porphyrin as linkers has been successfully synthesized and characterized. The single crystal X-ray diffraction indicated that this complex 1 exhibited a bilayered architecture of the porphyrins, which is seldom seen in MPFs. In addition, in vitro anticancer activity of complex 1 on three human breast cancer cells (BT474, SKBr-3 and ZR-75-30) was further determined.

Crystal structures and third-order optical properties of three manganese(II) complexes constructed from N-heterocyclic and polycarboxylate ligands

Three new manganese(II) complexes, {[Mn(PTP)]2[Mn(PTP)(H2O)]}(BTA)2·2H2O (1), [Mn(PTP)(ODA)]2 (2), and [Mn(FTP)(ODA)]2·H2O (3), were synthesized by the reactions of manganese acetate and polycarboxylic acid in the presence of N-heterocyclic ligands (where PTP=4′-phenyl-2,2′:6′,2″-terpyridine, H3BTA=benzene-1,3,5-tricarboxylic acid, H2ODA=4,4′-oxydibenzoic acid, FTP=4′-(furan-2-yl)-2,2′:6′,2″-terpyridine). In complex 1, each BTA ligand serves as a μ 3-bridge to link three Mn(II) centers, whereas each Mn(II) center is coordinated by two BTA ligands. This connection mode results in a grid sheet. Complexes 2 and 3 have very similar molecular structures with Mn(II) centers connected by ODA ligands to result in ring-like arrays. We investigated the third-order nonlinear optical (NLO) properties of the three complexes by single beam Z-scan techniques. Complexes 1–3 exhibit strong third-order NLO reverse saturable absorption with NLO absorptive indices β=1.32×10−6, 3.01×10−6, and 9.42×10−6 m W−1, respectively. In addition, complex 1 shows all excellent self-focusing effect with an NLO refractive index of γ=1.25×10−12 m2 W−1. The third-order NLO susceptibility χ (3) of the three complexes were calculated as 47.55×10−8, 4.85×10−8, and 15.16×10−8 esu, respectively.

Five Co(ii) coordination polymers with different counter anions based on [3,5-di(4H-1,2,4-triazol-4-yl)benzoato]− ligand: directed synthesis, structures and magnetic properties

Five cobalt(ii) coordination polymers were synthesized by reactions of HL with varied cobalt(ii) salts and different templates under solvothermal conditions.

Structure and third-order nonlinear optical properties of the two-dimensional CoIIcoordination polymer [Co(1,2-BIB)(PA)]n{1,2-BIB is 1,2-bis[(1H-imidazol-1-yl)methyl]benzene and H2PA is phthalic acid}

The design of nonlinear optical (NLO) materials with large NLO responses has been a challenge for materials scientists and chemists. Recently, organic polymers have received attention regarding their NLO properties and fast nonlinear response, and clusters involving delocalizeddπ–pπ systems and conjugateddπ–pπ systems are expected to be a new class of NLO materials. Metal–organic coordination polymers combine the advantages of the organic and inorganic species. Thus far, tuning the third-order NLO properties of these materials has been a significant challenge. A two-dimensional coordination polymer, namely poly[(μ-benzene-1,2-dicarboxylato-κ3O1,O1′:O3){μ-1,2-bis[(1H-imidazol-1-yl)methyl]benzene-κ2N3:N3′}cobalt(II)], [Co(C8H4O4)(C14H14N4)]n, was synthesized by hydrothermal methods. In the structure, the CoIIion is pentacoordinated by two N atoms from two different 1,2-bis[(1H-imidazol-1-yl)methyl]benzene (1,2-BIB) ligands and three O atoms from two symmetry-related benzene-1,2-dicarboxylate (isophthalate, PA) anions. The pentacoordinated CoIIions are linked by PA ligands to form a chain structure parallel to thecaxis. Adjacent chains are further connected by 1,2-BIB ligands to produce a two-dimensional layered structure. The compound exhibits strong third-order nonlinear absorption and nonlinear refraction effects as a thin film. The third-order susceptibility χ(3)is calculated to be 1.07 × 10−8esu, which is much larger than the values found for pure inorganic semiconductors and some polymers.

High Anodic Performance of Co 1,3,5-Benzenetricarboxylate Coordination Polymers for Li-Ion Battery

We report the designed synthesis of Co 1,3,5-benzenetricarboxylate coordination polymers (CPs) via a straightforward hydrothermal method, in which three kinds of reaction solvents are selected to form CPs with various morphologies and dimensions. When tested as anode materials in Li-ion battery, the cycling stabilities of the three CoBTC CPs at a current density of 100 mA g(-1) have not evident difference; however, the reversible capacities are widely divergent when the current density is increased to 2 A g(-1). The optimized product CoBTC-EtOH maintains a reversible capacity of 473 mAh g(-1) at a rate of 2 A g(-1) after 500 galvanostatic charging/discharging cycles while retaining a nearly 100% Coulombic efficiency. The hollow microspherical morphology, accessible specific area, and the absence of coordination solvent of CoBTC-EtOH might be responsible for such difference. Furthermore, the ex situ soft X-ray absorption spectroscopy studies of CoBTC-EtOH under different states-of-charge suggest that the Co ions remain in the Co(2+) state during the charging/discharging process. Therefore, Li ions are inserted to the organic moiety (including the carboxylate groups and the benzene ring) of CoBTC without the direct engagement of Co ions during electrochemical cycling.

An Effective Strategy To Construct Novel Polyoxometalate-Based Hybrids by Deliberately Controlling Organic Ligand Transformation In Situ

Deliberately controlling organic ligand transformation in situ has remained a challenge for the construction of polyoxometalate (POM)-based inorganic-organic hybrids. In this work, four POM-based hybrids assembled from an in situ bifurcating organic ligand-[Cu2(DIBA)4](H3PMo12O40)·6H2O (1), [Cu2(DIBA)4](H4SiW12O40)·6H2O (2), [Ag(HDIBA)2](H2PMo12O40)·2H2O (3), [Ag3(HDIBA)2(H2O)][(P2W18O62)1/2]·4H2O (4) (DIBAH = 3,5-di(1H-imidazol-1-yl) benzoic acid)-have been designed and obtained under hydrothermal conditions. Compounds 1 and 2 are isostructural, displaying a three-dimensional (3D) 2-fold interpenetrating framework with two types of channels, and the bigger channels are occupied by Keggin polyoxoanions and crystallization water molecules, but only crystallization water molecules in the smaller ones. Compound 3 displays a 3D supramolecular structure constructed from {Ag(HDIBA)2} segments and PMo12O40(3-) polyoxoanions through hydrogen bonding interactions. Compound 4 shows a 3D 2-fold interpenetrating framework based on (3, 3, 4)-connected network, which is constructed from {Ag3(HDIBA)2}n chains and P2W18O62(6-) polyoxoanions as linkers. The DIBAH ligand was generated in situ from 3,5-di(1H-imidazol-1-yl)benzonitrile by deliberate design, which illustrates that the strategy to construct novel POM-based hybrids by controlling ligand transformation in situ is rational and feasible. In addition, the effects of the central metal and POMs on the structures of the target compounds were discussed. Finally, the electrochemical and photocatalytic properties of compounds 1-4 have been investigated in this paper.

Crystal structure of poly[bis-(ammonium) [bis-(μ4-benzene-1,3,5-tri-carboxyl-ato)dizincate] 1-methyl-pyrrolidin-2-one disolvate]

The title three-dimensional metal-organic framework (MOF) compound, {(NH4)2[Zn2(C9H3O6)2]·2C5H9NO} n , features an anionic framework constructed from Zn(2+) cations and benzene-1,3,5-tri-carboxyl-ate (BTC) organic anions. Charge balance is achieved by outer sphere ammonium cations formed by degradation of di-n-butyl-amine in the solvothermal synthesis of the compound. Binuclear {Zn2(COO)2} entities act as the framework's secondary building units. Each Zn(II) atom has a tetrahedral coordination environment with an O4 set of donor atoms. The three-dimensional framework adopts a rutile-type topology and channels are filled in an alternating fashion with ordered and disordered 1-methyl-pyrrolidin-2-one solvent mol-ecules and ammonium cations. The latter are held in the channels via four N-H⋯O hydrogen bonds, including three with the benzene-1,3,5-tri-carboxyl-ate ligands of the anionic framework and one with a 1-methyl-pyrrolidin-2-one solvent mol-ecule.

Bis(triethanolamine)bis(μ2-trimesato)dicobalt(II): a Co(II) dimer with an unreported two-dimensional supramolecular topology formed from triethanolamine and trimesic acid ligands

Supramolecular networks are an important subset in the field of coordination polymer (CP) frameworks and are widely encountered in crystal engineering research. The search for novel topologies continues to be a significant goal in CP chemistry. The dimeric compound bis(μ-5-carboxybenzene-1,3-dicarboxylato-κ(2)O(1):O(3))bis[(triethanolamine-κ(4)N,O,O',O'')cobalt(II)], [Co2(C9H4O6)2(C6H15NO3)2], formed from the coligands 5-carboxybenzene-1,3-dicarboxylate (tmaH(2-)) and triethanolamine (teaH3), namely [Co(μ2-tmaH)(teaH3)]2, was synthesized and characterized by single-crystal and powder X-ray diffraction analyses, IR spectroscopy, thermogravimetric analysis (TGA) and magnetic measurements. The crystal structure features a zero-dimensional molecular structure consisting of centrosymmetric macrocyclic dinuclear complexes. Four classical hydrogen bonds between carboxylate groups and hydroxyethyl arms stabilize and extend the molecules into a two-dimensional supramolecular network. The topological analysis indicates that an unreported (3,5)-binodal supramolecular topology with a short Schläfli symbol of (4.5.6)(4.5(5).6(3).7) can be achieved by means of intermolecular hydrogen bonds. The crystal structure accounts for the potential to obtain unique topological types from two excellent hydrogen-bonding candidates, i.e. tmaH3 and teaH3. A variable-temperature magnetic study shows the existence of antiferromagnetic behaviour in the complex.

Crystal structures, topological analysis and luminescence properties of three coordination polymers based on a semi-rigid ligand and N-donor ligand linkers

Three new mixed-ligand coordination polymers have been synthesized based on 3,3′-(anthracene-9,10-diyl)diacrylate acid and different N-donor ligands. Complex 2 displays rapid and selective sensing of Fe³⁺.

Synthesis, Crystal Structure, and Theoretical Calculations of Two Cobalt, Nickel Coordination Polymers with 5-Nitroisophthalic Acid and Bis(imidazol) Ligands

Two new complexes [Co(NIPH)(bimb)(H2O)]n (1) and [Ni(NIPH)(mbix)]n (2) (H2NIPH = 5-nitroisophthalic acid, bimb = 1,4-bis(imidazol-1-yl)butane, mbix = 1,3-bis(imidazol-1-ylmethyl)benzene) have been hydrothermally synthesised and structurally characterised by elemental analysis, IR spectroscopy, thermogravimetric analysis, UV spectroscopy, and single-crystal X-ray diffraction. Complex 1 exhibits a two-dimensional (2D) network, which was stabilised through O–H···O and C–H···O hydrogen-bonding interactions. Complex 2 shows a two-dimensional (2D) network structure, which was further extended into a three-dimensional supramolecular structure through C–H···O hydrogen bonds and π–π interactions. Moreover, we analysed the natural bond orbital (NBO) using the PBE0/LANL2DZ method in the Gaussian 03 program. The calculation results indicated the obvious covalent interactions between the coordinated atoms and the CoII or NiII ion.

Syntheses, structures and properties of five entangled coordination polymers constructed with trigonal N-donor ligands

Five new entangled coordination polymers, which are based on large trigonal N-donor ligands and polycarboxylates, are reported. They display different entangled nets with self-penetrating, polythreading, interdigitation and interpenetration features.

A unique 3D metal-organic framework based on a 12-connected pentanuclear Cd(II) cluster exhibiting proton conduction

Solvothermal reaction of a TCA (TCA = 4,4',4''-tricarboxytriphenylamine) ligand with Cd(NO3)2 yielded a unique 3D 12-connected metal-organic framework of , which can be simplified as a (3,3,12)-connected 3-nodal net with a Schläfli symbol of {4(16)·6(36)·8(14)}{4(2)·6}2{4(3)}2 based on a 12-connected node of a pentanuclear Cd(ii) cluster and a three-connected organic linker of TCA. Compound exhibits both photoluminescence and proton conductivity. The luminescence properties of originate from the triphenylamine chromophore of the TCA ligand. The proton conductivity of is supposed to be relevant to the structure attributes of . On the one hand, the curved narrow channels lined with a hydrophilic pentanuclear Cd(ii) cluster in can improve the water affinity of framework and facilitate the water absorption under humid conditions. On the other hand, the coordinated water molecules within the pentanuclear Cd(ii) cluster can produce a mobile H(+) proton due to coordination activation. At 80 °C and 85% RH (relative humidity), compound shows the proton conductivity of 1.45 × 10(-6) S cm(-1).

Syntheses, crystal structures, luminescent and magnetic properties of two molecular solids containing naphthylmethylene triphenylphosphinium cations and tetra(isothiocyanate)cobalt(II) dianion

The reaction of CoCl2 with the naphthalene methylated triphenylphosphinium bromide [n-NAPMeTPP]Br (n=1, 2) and KSCN, in a methanolic medium at ambient temperature, leads to the self-assembly formation of hybrid 2:1 organic-inorganic molecular solids, [1-NAPMeTPP]2[Co(NCS)4](1) and [2-NAPMeTPP]2[Co(NCS)4](2) ([NAPMeTPP](+)=(naphthylmethylene)(triphenyl)phosphinium), which have been characterized by elemental analyses, IR spectroscopy, UV-Vis spectra, ESI-MS, molar conductivity and single-crystal X-ray diffraction structural analyses. Compound 1 crystallizes in the orthorhombic space group Pna21, while 2 does in the monoclinic space group C2/c. The cations form a dimer through the weak intermolecular C-H⋯π interactions in 1 and π⋯π interaction in 2, while the anion and cation are linked by the C-H⋯S hydrogen bond in 1. Two molecular solids show dual functionalities: (1) the broad fluorescence emission around 400nm in the solid state at room temperature; (2) the weak antiferromagnetic coupling behavior.