Three-dimensional Coordination Framework Research Articles

Cationic Cu(II)-MOF with 6-C Uni-Nodal Network: Photocatalytic degradation of Rose Bengal dye and notable colorimetric recognition of TEA and 2,4-DNP

A newly synthesized metal–organic framework material, designated as {[Cu(Bimb)3]∙(H2O)2∙2I}n(1),was produced by synthesizing through a solvothermal process, where (Bimb) 1,4-bis[(1H-imidazol-1-yl)methyl]benzene and CuI were involved. Crystal properties were meticulously characterized using advanced techniques such as Scanning Electron Microscopy (SEM), Single crystal X-ray Diffraction (SCXRD), Powder X-ray Diffraction (PXRD), Energy Dispersive X-ray Spectroscopy (EDX) and Elemental Mapping. These analyses showed a strong three-dimensional coordination framework with exceptional thermal and structural stability. Furthermore, luminescence experiments carried out on (1) displays its exceptional capacity for sensing Triethylamine (TEA) and 2,4-Dinitrophenol (2,4-DNP) to the LOD of 3.16 × 10−6 M (0.319 ppm) and 4.6 × 10−7 M (0.084 ppm) respectively. Furthermore, a study conducted on (1), demonstrated that it possesses an outstanding photocatalytic degradation of Rose Bengal (96.72 %,), Methyl Violet (88.23 %,), and Bisphenol B (88.35 %), dyesrespectively. This indicates that (1) has a significant potential to address environmental contamination concerns due to the sensing and photocatalytic properties that it possesses.

A three-dimensional Pb-centered coordination framework: crystal structure and electrochemiluminescent property

A three-dimensional Pb-centered coordination framework: crystal structure and electrochemiluminescent property

Lanthanide Hexacyanidoruthenate Frameworks for Multicolor to White-Light Emission Realized by the Combination of d-d, d-f, and f-f Electronic Transitions.

We report an effective strategy toward tunable room-temperature multicolor to white-light emission realized by mixing three different lanthanide ions (Sm3+, Tb3+, and Ce3+) in three-dimensional (3D) coordination frameworks based on hexacyanidoruthenate(II) metalloligands. Mono-lanthanide compounds, K{LnIII(H2O)n[RuII(CN)6]}·mH2O (1, Ln = La, n = 3, m = 1.2; 2, Ln = Ce, n = 3, m = 1.3; 3, Ln = Sm, n = 2, m = 2.4; 4, Ln = Tb, n = 2, m = 2.4) are 3D cyanido-bridged networks based on the Ln-NC-Ru linkages, with cavities occupied by K+ ions and water molecules. They crystallize differently for larger (1, 2) and smaller (3, 4) lanthanides, in the hexagonal P63/m or the orthorhombic Cmcm space groups, respectively. All exhibit luminescence under the UV excitation, including weak blue emission in 1 due to the d-d 3T1g → 1A1g electronic transition of RuII, as well as much stronger blue emission in 2 related to the d-f 2D3/2 → 2F5/2,7/2 transitions of CeIII, red emission in 3 due to the f-f 4G5/2 → 6H5/2,7/2,9/2,11/2 transitions of SmIII, and green emission in 4 related to the f-f 5D4 → 7F6,5,4,3 transitions of TbIII. The lanthanide emissions, especially those of SmIII, take advantage of the RuII-to-LnIII energy transfer. The CeIII and TbIII emissions are also supported by the excitation of the d-f electronic states. Exploring emission features of the LnIII-RuII networks, two series of heterobi-lanthanide systems, K{SmxCe1-x(H2O)n[Ru(CN)6]}·mH2O (x = 0.47, 0.88, 0.88, 0.99, 0.998; 5-9) and K{TbxCe1-x(H2O)n[Ru(CN)6]}·mH2O (x = 0.56, 0.65, 0.93, 0.99, 0.997; 10-14) were prepared. They exhibit the composition- and excitation-dependent tuning of emission from blue to red and blue to green, respectively. Finally, the heterotri-lanthanide system of the K{Sm0.4Tb0.599Ce0.001(H2O)2[Ru(CN)6]}·2.5H2O (15) composition shows the rich emission spectrum consisting of the peaks related to CeIII, TbIII, and SmIII centers, which gives the emission color tuning from blue to orange and white-light emission of the CIE 1931 xy parameters of 0.325, 0.333.

Guest-induced pore breathing controls the spin state in a cyanido-bridged framework.

Iron(ii) spin cross-over (SCO) compounds combine a thermally driven transition from the diamagnetic low-spin (LS) state to the paramagnetic high-spin (HS) state with a distinct change in the crystal lattice volume. Inversely, if the crystal lattice volume was modulated post-synthetically, the spin state of the compound could be tunable, resulting in the inverse effect for SCO. Herein, we demonstrate such a spin-state tuning in a breathing cyanido-bridged porous coordination polymer (PCP), where the volume change resulting from guest-induced gate-opening and -closing directly affects its spin state. We report the synthesis of a three-dimensional coordination framework {[FeII(4-CNpy)4]2[WIV(CN)8]·4H2O}n (1·4H2O; 4-CNpy = 4-cyanopyridine), which demonstrates a SCO phenomenon characterized by strong elastic frustration. This leads to a 48 K wide hysteresis loop above 140 K, but below this temperature results in a very gradual and incomplete SCO transition. 1·4H2O was activated under mild conditions, producing the nonporous {[FeII(4-CNpy)4]2[WIV(CN)8]}n (1) via a single-crystal-to-single-crystal process involving a 7.3% volume decrease, which shows complete and nonhysteretic SCO at T1/2 = 93 K. The low-temperature photoswitching behavior in 1 and 1·4H2O manifested the characteristic elasticity of the frameworks; 1 can be quantitatively converted into a metastable HS state after 638 nm light irradiation, while the photoactivation of 1·4H2O is only partial. Furthermore, nonporous 1 adsorbed CO2 molecules in a gated process, leading to {[FeII(4-CNpy)4]2[WIV(CN)8]·4CO2}n (1·4CO2), which resulted in a 15% volume increase and stabilization of the HS state in the whole temperature range down to 2 K. The demonstrated post-synthetic guest-exchange employing common gases is an efficient approach for tuning the spin state in breathing SCO-PCPs.

Crystal structure of poly[(μ6-benzene-1,3,5-tricarboxylato)tris(1-methylpyrrolidin-2-one)nitratodizinc(II)

The asymmetric unit of the title compound, [Zn2(C9H3O6)(NO3)(C5H9NO)3] n , I, consists of two different zinc(II) ions bridged by the carboxylate group of benzene-1,3,5-tricarboxylate (BTC3−). The Zn1 center is tetra-coordinated by the carboxylate O atoms of three symmetrically equivalent BTC3− anions and one nitrate O atom in a distorted tetrahedral geometry with Zn—Ocarboxylate bond lengths (average value 1.958 Å) slightly shorter than the Zn—Onitrate distance [2.013 (6) Å]. The Zn2 center is hexa-coordinated by three O atoms from the carboxylic groups of different BTC3− linkers and three O atoms of 1-methylpyrrolidin-2-one (NMP) in a slightly distorted octahedral geometry with nearly equivalent Zn—O bond lengths (average values of 2.091 and 2.088 Å, respectively). Linking of the paddle-wheel dizinc building units by the three carboxylate groups of the BTC3− molecule results in the formation of the three-dimensional coordination framework.

A Three-Dimensional Coordination Framework with a Ferromagnetic Coupled Ni(II)-CrO4 Layer: Synthesis, Structure, and Magnetic Studies.

We report herein on the crystal structure and magnetic studies of a three-dimensional (3D) Ni(II)-chromate coordination polymer, [Ni(CrO4)(bpym)(H2O)]n (1; bpym = 5,5′-bipyrimidin), prepared by self-assembly of Ni(II) and chromate ions with a multi-N donor auxiliary ligands, bpym, through hydrothermal processes. The structure of 1 is composed of Ni(II)-CrO4 layers with [Ni3(μ3-CrO4)] triangular motifs, in which the Ni(II) centers are bridged by O′:O′:O′:μ3-CrO42− anions, and the resulting layers are further connected by twisted trans-μ2-N,N′-bpym auxiliary ligands to form a 3D pillar-layered network with an hms topology. The magnetic properties of compound 1 were illustrated by variable field and temperature magnetic susceptibility measurements. The findings reveal that compound 1 shows intralayer ferromagnetic interactions within Ni(II)-CrO4 layers, and furthers the 3D antiferromagnetic ordering in the resulting of interlayer antiferromagnetic couplings with a Néel temperature (TN) of 5.6 K. In addition, compound 1 shows the field-induced metamagnetic behavior at temperature below the TN.

Magnetic interactions controlled by light in the family of Fe(II)-M(IV) (M = Mo, W, Nb) hybrid organic-inorganic frameworks.

Three new hybrid organic-inorganic frameworks employing octacyanidometallates and 4,4'-bypiridine dioxide (4,4'-bpdo) as bridging molecules were prepared and characterized. The three-dimensional coordination frameworks {[FeII(μ-4,4'-bpdo)(H2O)2]2[MIV(CN)8]·9H2O}n (Fe2Mo, Fe2W and Fe2Nb; M = Mo, W and Nb) are composed of cyanido-bridged chains, which are interconnected by the organic linkers. Magnetic measurements for Fe2Nb show a two-step transition to the antiferromagnetic state, which results from the cooperation of antiferromagnetic intra- and inter-chain interactions. Fe2Mo and Fe2W, on the other hand, behave as paramagnets at 2 K because of the diamagnetic character of the corresponding octacyanidometallate(IV) building units. However, after 450 nm light irradiation they show transition to the metastable high spin MoIV or WIV states, respectively, with distinct ferromagnetic intrachain spin interactions, as opposed to the antiferromagnetic ones observed in the Fe2Nb framework.

A fourfold interpenetrating three-dimensional cadmium(II) coordination polymer: synthesis, crystal structure and physical properties.

A novel three-dimensional CdII coordination framework, namely, poly[{μ-bis[4-(2-methylimidazol-1-yl)phenyl] ether-κ2N3:N3'}(μ-naphthalene-1,4-dicarboxylato-κ3O1:O4,O4')cadmium(II)], [Cd(C12H6O4)(C20H18N4O)]n or [Cd(1,4-NDC)(BMIOPE)]n, where 1,4-H2NDC is naphthalene-1,4-dicarboxylic acid and BMIOPE is bis[4-(2-methylimidazol-1-yl)phenyl] ether, has been prepared and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy and thermogravimetric analysis. The compound displays a novel fourfold interpenetrating diamond-like network. In addition, it not only shows a strong fluorescence emission in the solid state, but also exhibits excellent photocatalytic activity for the degradation of methylene blue (MB) at room temperature.

Crystal structures and temperature-dependent photoluminescence of lanthanide coordination frameworks of mixed-benzenedicarboxylates

A new series of non-porous, three-dimensional coordination frameworks, i.e. [LnIII(bdc)0.5(phth)(H2O)2], where LnIII = EuIII, TbIII, HoIII, ErIII and TmIII, phth2- = 1,2-benzenedicarboxylate, and bdc2- = 1,4-benzenedicarboxylate, were synthesized and characterized. The frameworks have two-dimensional sheets of which the stoichiometry is the same as the framework containing only phth2-. Architecture, topology and thermal stability of the frameworks were examined. Temperature-dependent photoluminescent properties of the EuIII and TbIII frameworks were studied and discussed with reference to those containing only phth2- and bdc2-. The mixed EuIII/TbIII frameworks were also prepared and their temperature-dependent photoluminescent properties were investigated, revealing energy transfer from TbIII to EuIII and its dependence on EuIII content.

Dy(III) and Sm(III) Coordination Polymers Based on 2,4-Pyridinedicarboxylic Acid: Synthesis, Structures, Luminescence and Magnetism

Two new coordination polymers [Dy3(PDA)4(HO)(H2O)2]·6H2O (1) H2[(H3O)Sm3(PDA)6]·14H2O (2) (H2PDA = 2,4-pyridinedicarboxylic acid), have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, XRD as well as single-crystal X-ray diffraction. They display different three-dimensional coordination frameworks, in which 2,4-PDA exhibits μ4-(κ5N,O2:O2′:O4:O4′), μ4-(κ5N,O2:O2,O2′:O4:O4′) and μ1-(κ5N,O2) coordination modes. Their topological structures have been analyzed. It is interesting that they have the same topological structure. The luminescence properties of 1 and 2 were determined with solid samples. They show the exclusive luminescence emission of Dy(III) or Sm(III) ions, respectively. The magnetic properties of 1 were also studied. It displays antiferromagnetic Dy(III)···Dy(III) interactions. CCDC 1945187 and 1945188 for complexes 1 and 2, respectively.

Synthesis, structures and luminescence of two lanthanide coordination polymers based on 2,4-pyridinedicarboxylic acid

Two Lanthanide coordination polymers [(H3O)Eu3(PDA)6]2-·2H3O+·12H2O (1) and [Tb3(PDA)4(HO)(H2O)2]·2H2O (2) (H2PDA = 2,4-pyridinedicarboxylic acid), have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, XRD as well as single-crystal X-ray diffraction. Both complexes are crystallized in the tetragonal system, P41212 space group, but they have different three-dimensional coordination frameworks. 2,4-PDA2- ligand exhibits μ4-(κ5N,O2:O2’:O4:O4’), μ4-(κ5N,O2:O2,O2’:O4:O4’) and μ1-(κ5N,O2) coordination modes in the complexes. Both of them can be simplified to a new topology, with the Schläfli symbol of {36‧416‧56}. The luminescence properties for the two complexes were determined with solid samples. Complexes 1 and 2 show typical red and bright-green luminescence of EuIII and TbIII, respectively.

Two alkaline earth metal coordination polymers based on a new oxamate-dicarboxylate ligand: Selective fluorescence sensing of Fe3+ in aqueous solution

Two different alkaline earth metal coordination polymers (AE-CPs) {[Ca3L2(H2O)6]·2H2O}n (1) and [Sr(H2L)2]n (2) were constructed from using 5-(ethyl oxamate)-isophthalic acid (H2EtL) ligand with alkaline earth metal ions Ca2+ and Sr2+ under solvothermal conditions, respectively. Among them, L and H2L are formed by in-situ hydrolysis of H2EtL, which display multiple kinds of coordinated modes through oxamate and carboxylate groups. 1 and 2 both show three-dimensional coordination frameworks possessing unprecedented (3,4,5)-connected skg1 topology and (3,6)-connected ant topology, respectively. The solid-state fluorescence properties of 1 and 2 were studied, and 1 with bright blue luminescence reveals selective sensing toward Fe3+ ion in water with the low detection limit (LOD) of 1.04 × 10−3 M.

Crystal structure of a low-spin poly[di-μ3-cyanido-di-μ2-cyanido-bis-(μ2-2-ethyl-pyrazine)-dicopper(I)iron(II)

In the title metal-organic framework, [Fe(C6H8N2)2{Cu(CN)2}2] n , the low-spin FeII ion lies at an inversion centre and displays an elongated octa-hedral [FeN6] coordination environment. The axial positions are occupied by two symmetry-related bridging 2-ethyl-pyrazine ligands, while the equatorial positions are occupied by four N atoms of two pairs of symmetry-related cyanide groups. The CuI centre is coordinated by three cyanide carbon atoms and one N atom of a bridging 2-ethyl-pyrazine mol-ecule, which form a tetra-hedral coordination environment. Two neighbouring Cu atoms have a short Cu⋯Cu contact [2.4662 (7) Å] and their coordination tetra-hedra are connected through a common edge between two C atoms of cyanide groups. Each Cu2(CN)2 unit, formed by two neighbouring Cu atoms bridged by two carbons from a pair of μ-CN groups, is connected to six FeII centres via two bridging 2-ethyl-pyrazine mol-ecules and four cyanide groups, resulting in the formation of a polymeric three-dimensional metal-organic coordination framework.

A fourfold interpenetrating diamond-like three-dimensional zinc(II) coordination polymer: synthesis, crystal structure and physical properties.

Excellent fluorescence properties are exhibited by d10 metal compounds. The novel three-dimensional ZnII coordination framework, poly[[{μ2-bis[4-(2-methyl-1H-imidazol-1-yl)phenyl] ether-κ2N3:N3'}(μ2-furan-2,5-dicarboxylato-κ2O2:O5)zinc(II)] 1.76-hydrate], {[Zn(C6H2O5)(C20H18N4O)]·1.76H2O}n, has been prepared and characterized using IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The crystal structure analysis revealed that the compound exhibits a novel fourfold interpenetrating diamond-like network. This polymer also displays a strong fluorescence emission in the solid state at room temperature.

Visualization of Anisotropic and Stepwise Piezofluorochromism in an MOF Single Crystal

Summary Metal-organic frameworks (MOFs) have intriguing and tunable photophysical properties owing to predesignable structures from well-defined metal and/or organic chromophores. We propose a one-pot two-step assembly strategy for engineering dual-functional coordination interspace where two kinds of organic linkers are segregated in predefined positions. This design endows the three-dimensional coordination framework with unidirectional deformation character, leading to an orientation-dependent and pressure-responsive photoluminescence color change. For the first time, unique piezofluorochromic anisotropism is achieved and can be accumulated stepwise and visualized by a metal-organic framework single crystal, providing a basic model for application in stimuli-responsive photoluminescence sensing, barcoding, signal switching, harvesting, and magnifying micro-devices.

Coordination polymers based on zinc(ii) and manganese(ii) with 1,4-cyclohexanedicarboxylic acid

Three new metal-organic coordination polymers were obtained namely, [Mn3(chdc)3-(NMP)2(DMF)2] (1, chdc2– is trans-1,4-cyclohexanedicarboxylate, NMP is N-methylpyrrolidone, DMF is N,N-dimethylformamide), [Zn3(chdc)3(NMP)2]•2NMP (2), and [Zn3(chdc)3(ur)-(DMF)0.5]•DMF (3, ur is the urotropine). The crystal structures of polymers 1, 2, and 3 were determined by single-crystal X-ray crystallography. All three compounds were found to contain a trinuclear secondary building unit {M3(OOC)6}. Coordination polymers 1 and 2 have a layered structure, while polymer 3 has a three-dimensional coordination framework with isolated pores formed due to the presence of urotropine bridging molecules. Compounds 1 and 3 were characterized by IR spectroscopy, thermogravimetric and elemental analysis data, powder X-ray diffraction. Compound 3 was also characterized by UV-Vis diffuse reflectance spectrum.

Photoactive and Physical Properties of an Azobenzene-Containing Coordination Framework

A new three-dimensional coordination framework, [Zn4(tbazip)3(bpe)2(OH)2]·bpe·{solvent} (where bpe = 1,2-di(4-pyridyl)ethene) containing the novel photoactive ligand tbazip (tbazip = 5-((4-tert-butyl)phenylazo)isophthalic acid) has been synthesised and crystallographically characterised. The photoactivity of discrete tbazip was investigated and compared with its photoactivity while incorporated within the framework. The effect of isomerisation of the incorporated azobenzene on the chemical and physical properties of the framework were investigated using UV-vis and Raman spectroscopies. The framework is porous only to hydrogen gas at 77 K, but displayed an appreciable uptake for CO2 at 195 K.

Silver(I) coordination polymers generated from asymmetrical Schiff-base ligands containing triazolyl and pyridyl rings

A series of the silver(I) complexes of the type {[Ag(L1)][X]}∞ [L1=4-(pyridin-2-yl)methyleneamino-1,2,4-triazole; X=PF6−, 1, BF4−, 2, ClO4−, 3, and NO3−, 4], {[Ag(L2)(CH3CN)][PF6]}n (L2=4-(pyridin-3-yl)methyleneamino-1,2,4-triazole), 5, and {[Ag(L2)][CF3CO2]}n, 6, have been prepared by reactions of various Ag(I) salts with L1 or L2 in CH3CN. All the complexes have been structurally characterized by X-ray crystallography confirming that complexes 1–4 are one-dimensional coordination polymeric chains, while complexes 5 and 6 are two-dimensional and three-dimensional coordination polymeric net and frameworks, respectively. All the L1 ligands in complexes 1–4 act as tridentate ligands to chelate and bridge Ag(I) ions. The anions PF6−, BF4− and ClO4− in complexes 1–3 are not coordinated to the Ag(I) atoms while the NO3− anions in complex 4 are coordinated to the metal centers through one of the three oxygen atoms. All the tridentate L2 ligands in complexes 5 and 6 bind soft acid Ag(I) ions through the triazole and pyridyl groups forming the two-dimensional and three-dimensional coordination polymeric net and frameworks, respectively, while the anions PF6− and CF3CO2− in complexes 5 and 6 are not coordinated to the Ag(I) atoms. The anions in complexes 1–6 play important roles in linking cationic chains or layers into 3-D supramolecular structures.

Synthesis, Structures, and Properties of 3D Lanthanide (III) Coordination Polymers Based on 5-Nitroisophthalic Acid

A three lanthanide-based coordination compounds of [Sm4(NIPH)5(ox)(H2O)5](H2O)4 (1), [Eu4(NIPH)5(oba)(H2O)5](H2O) (2) and [Eu2(NIPH)3(H2O)14](H2NIPH)(H2O)6 (3) (H2NIPH = 5-nitroisophthalic acid, ox = oxalic acid, H2oba = 4,4′-oxydibenzoic acid) were synthesized by hydrothermal reaction and characterized by single-crystal X-ray diffraction. These compounds contain an -Ln-O-C-O-Ln- zigzag chain, which connect to each other through the oxygen atoms of the H2NIPH ligands to form a wave-like layer. These layers are bridged by oxalate or H2NIPH ligands to generate three-dimensional coordination framework. Within these compounds, porous structure with one-dimensional channels which were filled with isolated organic ligands or lattice water molecules are also observed. Fascinatingly, these lattice water molecules display unprecedented water morphology and play important roles in the stabilizing the whole network. In addition, these compounds show strong photoluminescence at room temperature, respectively, and may be good candidates for potential luminescence materials.

Two kinds of 3D coordination frameworks from monometallic to 4d–4f heterometallic: Synthesis, crystal structures, photoluminescence and magnetic properties

Two kinds of three-dimensional (3D) coordination frameworks from monometallic to heterometallic, including a charming 3D monometallic complex, namely, [Eu2(mpda)3(H2O)4]n (1) and the first series of novel 3D heterometallic 4d–4f coordination frameworks based on 2,6-dimethylpyridine-3,5-dicarboxylic acid, namely, [Ln2Cd2(mpda)2(bdc)2(SO4)2(H2O)6]n [Ln=Sm(2), Eu(3), Gd(4), Tb(5), Dy(6); mpda=2,6-dimethylpyridine-3,5-dicarboxylic acid; bdc=1,4-benzenedicarboxylic acid] have been successfully synthesized under hydrothermal conditions and structurally characterized. Crystal 1 is featured by its interesting 3D chain-layer construction which is formed by the alternative arrangement of chains and layers and exhibits 2-nodal 5, 6-connected 3D network with the Schlafli symbol of {33.43.55.64}{36.46.53}. Complexes 2–6 are isostructural and it reveals that these 3D heterometallic compounds are firstly built by H2mpda ligand. What is worth mentioning is that anionic ligand SO42− plays a crucial function in the construction building. The two-dimensional (2D) lanthanide-transition heterometallic bilayers [Ln2Cd2(mpda)2(bdc)2]n are pillared by SO42− subunits forming mixed-ligand complexes with a pillared-layer 3D structure. Complexes 2–6 feature 4-nodal 3, 4, 5, 6-connected 3D frameworks with {4.82}{4.84.10}{42.810.102.12}{42.88} topology. All the complexes are characterized by elemental analyses, FT-IR spectroscopy, Powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Furthermore, the luminescence properties of compounds 1, 3, and 5 and the magnetic properties of complexes 4 and 6 were also investigated in detail.