Sulfonyldibenzoic Acid Research Articles

Rational Tuning the Proton Conductivity and Stability of Hydrogen-Bonded Organic Frameworks.

In the development of proton conductors, it is crucial to regulate proton conduction pathways and enhance structural stability. In this study, we designed and constructed three hydrogen-bonded organic frameworks (HOFs), namely, NKM-HOF-9, NKM-HOF-10, and NKM-HOF-11, with different dimensional hydrogen-bonding pathways using 4,4'-sulfonyldibenzoic acid and various bases. They are cost-effective and easy to synthesize, allowing for their large-scale production at room temperature. By purposefully altering the ammonium ions, we achieved enhancements in the conductivity and stability of these HOFs. Proton conductivity studies at different humidities and temperatures revealed that at 85 °C and 98% relative humidity, the proton conductivity of NKM-HOF-10 reached 1.7 × 10-3 S cm-1, surpassing that of NKM-HOF-9 by 1 order of magnitude. This improvement was accomplished by increasing the number of proton donors from the base, which resulted in a transition of the hydrogen bond network from discontinuous to continuous, thereby enhancing the proton conduction performance. Moreover, stability tests showed that raising the base's pKa could improve the stability of these frameworks. NKM-HOF-11, which features the highest pKa, demonstrated superior stability by maintaining its structural integrity even at 450 °C.

Multiresponsive luminescent metal–organic framework for cooking oil adulteration detection and gallium(III) sensing

A new 3D metal–organic framework {[Cd16(tr2btd)10(dcdps)16(H2O)3(EtOH)]∙15DMF}n (MOF 1, tr2btd = 4,7-di(1,2,4-triazol-1-yl)benzo-2,1,3-thiadiazole, H2dcdps = 4,4′-sulfonyldibenzoic acid) was obtained and its luminescent properties were studied. MOF 1 exhibited bright blue-green luminescence with a high quantum yield of 74 % and luminescence quenching response to a toxic natural polyphenol gossypol and luminescence enhancement response to some trivalent metal cations (Fe3+, Cr3+, Al3+ and Ga3+). The limit of gossypol detection was 0.20 µM and the determination was not interfered by the components of the cottonseed oil. The limit of detection of gallium(III) was 1.1 µM. It was demonstrated that MOF 1 may be used for distinguishing between the genuine sunflower oil and oil adulterated by crude cottonseed oil through qualitative luminescent and quantitative visual gossypol determination.

High yield, large-scale synthesis of calcium-based microporous metal-organic framework and examination of the long-term stability for xenon adsorption applications

Scale-up synthesis of calcium-based microporous metal-organic framework (SBMOF-1) up to ∼400 g in a batch with a yield of >90 % was achieved by a solvothermal reaction of sulfonyldibenzoic acid (SDB) with an excess of calcium chloride. Here, we observed that recrystallization of unreacted SDB at a solvothermal condition caused a moderate reaction yield (40–50 %) at the reference condition of CCaCl2/ CSDB = 1 and CSDB/ CSDB(ref) = 1. Simply adding more reagents to the reactor did not increase the mass of product formed per unit volume due to a more pronounced loss of the yield at those conditions. By simultaneously changing the molar ratio of CaCl2 to SDB, CCaCl2/ CSDB, and the molar concentration of the SDB reagent, CSDB/ CSDB(ref), we explored %yield of the reaction. Interestingly, a linear improvement in the yield was observed from 21 % (at CCaCl2/ CSDB = 0.5) up to 78 % (at CCaCl2/ CSDB = 6) at a fixed ratio of CSDB/ CSDB(ref) = 2 and the yield leveled off after further addition. Unlike those at CCaCl2/ CSDB = 1, the yields at a high CaCl2 excess continued to improve with increasing the CSDB/ CSDB(ref). When a large pressure vessel (2500 mL EtOH, CCaCl2/ CSDB = 6, CSDB/ CSDB(ref) = 8) was used, about 415 g of SBMOF-1 with a yield of 92.3 % was produced, indicating 16 × the space yield improvement. The ability to synthesize SBMOF-1 on a large scale allowed us to examine the long-term stability of SBMOF-1 for almost 200 days in the presence of varying levels of relative humidity.

Pillar-layered metal-organic frameworks with benchmark C2H2/C2H4 and C2H6/C2H4 selectivity for one-step C2H4 production

Energy-efficient adsorptive separation shows great potential for the one-step production of high-purity ethylene (C2H4) from ternary C2 hydrocarbons. However, it remains a formidable challenge to fabricate high-performance adsorbents that exhibit simultaneous high selectivity (>2) towards acetylene/ethylene (C2H2/C2H4) and ethane/ethylene (C2H6/C2H4). Herein, we report a pillar-layered metal–organic framework, Ni(sdba)(dabco)0.5 (H2sdba = 4,4′-sulfonyldibenzoic acid; dabco = 1,4-diazabicyclo [2.2.2] octane), for preferential trapping of C2H6 and C2H2 over C2H4. The abundant accessible binding sites endow Ni(sdba)(dabco)0.5 with outstanding C2H2/C2H4 (2.28) and C2H6/C2H4 (2.47) selectivity with high C2H6 (3.15 mmol g−1) and C2H2 (4.41 mmol g−1) uptake among porous materials reported for one-step C2H4 purification. Dynamic breakthrough experiments demonstrated the feasibility of producing high-purity C2H4 (>99.9%) from C2H2/C2H6/C2H4 gas-mixtures (1/1/1 and 1/9/90, v/v/v) in a single step. Computational simulations reveal that the aromatic-rich pore spaces, which decorated with accessible interlayer uncoordinated oxygen atoms of sulfonyl groups and alkyl functionalities, can provide multiple C-H···O, C-H···π, and C-H···H interactions for selectively recognizing C2H6 and C2H2 over C2H4.

Synthesis, structure and dielectric behavior study of Mn (II)-4,4′-sulfonyldibenzoate-auxiliary ligand system based coordination polymers (CPs)

Based on MnCl2.4H2O, V-shaped ligand 4,4′-sulfonyldibenzoic acid (H2SBA), and two N-containing auxiliary ligands three new coordination polymers (CPs), namely: [Mn3(SBA)2(pyzc)2(DMA)2].DMA.H2O 1, [Mn3(SBA)2(phen)2(OAc)2].2DMA 2, and [Mn3(SBA)2(phen)2(OAc)2].2EtOH 3 [where, SBA = 4,4′-sulfonyldibenzoate, pyzc = 2-pyrazinecarboxylate, phen = 1,10-phenanthroline, OAc = acetate, DMF = N, N'-dimethylformamide, DMA = N, N'-dimethylacetamide] were synthesized using mixture of polar protic/aprotic solvents under solvothermal conditions. Single crystal X-ray study revealed that solid 1 is composed of tetrameric {Mn4O20N2} and dimeric units {Mn2O8N2}, whereas solids 2 and 3 are built of trimeric cluster {Mn3N2O14}. The structurally similar 2D coordination solids 2 and 3 showed comparable dielectric constant (ɛ'∼15.0) at room temperature. Solid 1 exhibited a higher value of dielectric constant (ɛ'∼30.5) probably due to the contribution from disordered polar guest solvent molecules, and 1D manganese carboxylate chains interaction. The crystal engineering of soluble 1:1 manganese carboxylate complex species, with or without coordination with an auxiliary ligand, is also explained mechanistically in this study. The approach not only provides a rationale for the composition and variation in the coordination linkage but also describes the crystal packing in terms of the dominant directional coordination and H-bonding forces.

Study on the structure regulation and electrochemical properties of imidazole-based MOFs by small molecules

In this work, four novel metal-organic frameworks (MOFs) were synthesized by the solvothermal reaction of the transition metal salts Co(NO3)2 with the mixed organic ligands 4,4′-sulfonyldibenzoic acid (H2SA) and 1,4-di(1H-imidazole-1-yl)-benzene (DIB) with the formula of [Co(DIB)0.5(SA)]•(DIB)0.5 (1), [Co(DIB)0.5(SA)] (2), [Co0.5(DIB)(HSA)]•(C10H8)0.5 (3) and [Co0.5(DIB)(HSA)]•(CH3CN) (4). Structural analysis manifested that complex 1 was assembled by the 2D Co-SA-DIB coordination networks constructed from the binuclear cobalt paddle-wheel secondary building units, while complex 3 was built from the 2D Co-DIB coordination networks based on the mononuclear cobalt center with the partially deprotonated HAS− ligand suspended on the two sides of the Co-DIB networks via the coordination between carboxylate and Co2+ cations. Furthermore, free DIB and naphthalene molecules functioned as the guest molecules to fill the pores in the structure of 1 and 3 respectively. More impressively, by just changing the used solvent, the free guest molecules DIB and naphthalene could be removed from the pores, and two novel MOFs, namely 2 and 4, could be obtained, whose framework architectures were identical to 1 and 3, respectively. In addition, the electrochemical properties of complexes 1–3 were checked as well and the results indicated that complex 3 exhibited the best electrocatalytic performance for the hydrogen evolution reaction (HER) with a low overpotential of 135 ​mV at the 10 ​mA ​cm−2 current density and a Tafel slope of 84 ​mV·dec−1. Moreover, it also possessed excellent stability with the maintainment of the current density up to 99.2% after 1000 cycles.

Pore-Directed Solid-State Selective Photoinduced E – Z Isomerization and Dimerization within Metal–Organic Frameworks

Pore-Directed Solid-State Selective Photoinduced <i>E</i> – <i>Z</i> Isomerization and Dimerization within Metal–Organic Frameworks

Two Polynuclear Manganese(II) Complexes Based on Multidentate N-Heterocyclic Aromatic Ligand and V-Shaped Polycarboxylate Ligand: Synthesis, Crystal Structure Analysis and Magnetic Properties

The reaction of MnCl2, 2-(5-{6-[5-(Pyrazin-2-yl)-1H-1,2,4-triazol-3-yl]pyridin-2-yl}-1H-1,2,4-triazol-3-yl)pyrazine (H2ptptp), 4,4′-sulfonyldibenzoic acid (H2sdba) or 4-(4-carboxyphenoxy)phthalate acid (H3cpop) and [BMI]Br ionic liquids (BMI = 1-butyl-3-methylimidazolium) gave rise to two complexes, {[Mn4(ptptp)2(sdba)2(H2O)2]·2H2O}n (1) and {[Mn3(ptptp)(cpop)Br(H2O)2]·2H2O}n (2). The compounds have been well characterized by elemental analysis, IR spectra, thermogravimetric analysis, as well as single-crystal and powder X-ray diffraction. The structure feature of 1 is that Mn(II) ions in the [Mn6(sdba)2] loops of V-shaped sdba2− ligands are ptptp2− ligands, respectively, and a 2D layer is constructed from sdba2− and ptptp2− ligands. The adjacent 2D layers are connected by O–H⋯N hydrogen bonds to form a 3D supramolecular network. The neighbouring trinuclear Mn(II) clusters in 2 are linked by V-shaped cpop3− ligands to give a 2D layer, which is penetrated by ptptp2− ligands to form self-threading structure. The results of variable-temperature magnetic studies have shown that the magnetic interactions between the Mn(II) ions in 1 and 2 are mainly due to antiferromagnetic coupling.

Synthesis, structure and fluorescence property of a new Zn-MOF based on a tetraphenylethane (TPE) ligand

A new 3D luminescent Zinc (II) metal-organic framework, has been solvothermally synthesized by using Zn(NO3)2⋅4H2O and a mixture of ligands: Titpe ligand and bcpf ligand. The molecular formula is [Zn(Titpe)(bcpf)•(DMF)]n, (Compound 1, Titpe = 1,1,2,2-tetrakis(4-(1H-imidazol-1-yl)phenyl)ethane, bcpf= 4,4΄-sulfonyldibenzoic acid). Compound 1 crystallizes in the triclinic system, space group P -1, with a=12.9990(9), b=14.2181(10), c=14.3781(10) Å, α = 89.974(4)°, β = 71.640(4)°, γ = 80.732(4)°, V = 2485.6(3) Å3, Z = 2, Mr = 1039.43, Dc =1.389 g/cm3, μ = 0.600 mm−1, F(000) = 1076.0, R = 0.0747 and wR =0.2508 for 9724 observed reflections (I > 2σ(I)). Topology analysis shows that compound 1 is a double interpenetrating structure. In addition, due to the ligand-to-ligand charge transfer of the TPE chromophore, luminescent spectra of 1 shows that it emits strong blue light. Compound 1 can detect Fe3+ ions with high selectivity and sensitivity among diverse inorganic cations in aqueous solution and is also a highly selective sensing material for CrO42− and Cr2O72- ions.

Isoreticular Chemistry of Group 13 Metal-Organic Framework Compounds Based on V-Shaped Linker Molecules: Exceptions to the Rule?

Following the concept of isoreticular chemistry, we carried out a systematic study on Ga-containing metal-organic frameworks (MOFs) using six V-shaped linker molecules of differing sizes, geometries, and additional functional groups. The linkers included three isophthalic acid derivatives (m-H2BDC-R, R = CH3, OCH3, NHCOCH3), thiophene-2,5-dicarboxylic acid (H2TDC), and two 4,4'-sulfonyldibenzoic acid derivatives (H2SDBA, DPSTA). The crystal structures of seven compounds were elucidated by a combination of model building, single-crystal X-ray diffraction (SCXRD), three-dimensional electron diffraction (3D ED), and Rietveld refinements against powder X-ray diffraction (PXRD) data. Four new Ga-MOFs that are isoreticular with their aluminum counterparts, i.e. Ga-CAU-10-R (Ga(OH)(m-BDC-R); R = OCH3, NHCOCH3), Ga-CAU-11 (Ga(OH)(SDBA)), and Ga-CAU-11-COOH (Ga(OH)(H2DPSTC)), were obtained. For the first time large single crystals of a MOF crystallizing in the CAU-10 structure type could be isolated, i.e. Ga-CAU-10-OCH3, which permitted a detailed structural characterization. In addition, the use of 5-methylisophthalic acid and thiophene-2,5-dicarboxylic acid resulted in two new Ga-MOFs denoted Ga-CAU-49 and Ga-CAU-51, respectively, which are not isostructural with any known Al-MOF. The crystal structure of Ga-CAU-49 ([Ga4(m-HBDC-CH3)2(m-BDC-CH3)3(OH)4(H2O)]) contains an unprecedented rod-shaped inorganic building unit (IBU) of the formula ∞1{Ga16(OH)18O60}, composed of corner-sharing GaO5 and GaO6 polyhedra. In Ga-CAU-51 ([Ga(OH)(C5H2O2S)]) chains of alternating cis and trans corner-sharing GaO6 polyhedra form the IBU. A detailed characterization of the title compounds was carried out, including nitrogen gas and water vapor sorption measurements. Ga-CAU-11 was the only compound exhibiting porosity toward nitrogen with a type I isotherm, a specific surface area of aS,BET = 210 m2/g, and a micropore volume of Vmic = 0.09 cm3/g. The new MOF Ga-CAU-51 exhibits exceptional water sorption properties with a reversible S-shaped isotherm and a high uptake around p/p0 = 0.38 of mads = 370 mg/g.

Synthesis and characterization of soluble and heat-resistant aromatic polyamides derived from diamine; N-(3,5-diaminophenyl)-4-(naphthalen-7-yloxy)benzamide and various aromatic diacids

The new aromatic m-catenated diamine, N-(3,5-diaminophenyl)-4-(naphthalen-7-yloxy)benzamide was synthesized from 2-naphthol and 4-fluoro benzonitrile as starting materials. A series of novel aromatic polyamides were synthesized from the diamine and several aromatic diacids such as 4,4′-Oxydibenzoic acid, Naphthalene-2, 6-dicarboxylic acid, 4,4′-Sulfonyldibenzoic acid, Biphenyl-4,4′-dicarboxylic acid and 4,4′-(perfluoropropane-2, 2-diyl) dibenzoic acid via direct Yamazaki’s phosphorylative polycondensation method with triphenyl phosphite (TPP) as a condensing agent in pyridine (Py)/LiCl/1-methyl-2-pyrrolidone (NMP) solvent system. These new m-catenated/kink structured polyamides containing pendant naphthalene-oxy-benzamide units, were characterized by inherent viscosities, solubility in organic solvents, FTIR, DSC, TGA and XRD techniques. The polyamides were obtained in good yields and had inherent viscosities in range 0.35 and 0.55 dL/g. These polyamides were soluble in amide type aprotic solvents namely N, N′ dimethyl formamide (DMF), N-methyl-2-pyrrolidone (NMP), N, N′ dimethyl acetamide (DMAc), dimethyl sulfoxide (DMSO) and partly soluble in m-cresol, tetrahydrofuran (THF) and chloroform or dichloromethane. Polyamides showed glass-transition temperatures in the range 224 °C–262 °C indicating their processability at these temperatures. Thermogravimetric analysis in nitrogen atmosphere showed the 10% weight loss temperatures were more than 555 °C, indicating a good thermal stability. X-ray diffraction patterns of these polyamides indicated the amorphous nature, which is reflected in solubility characteristics.

A single-crystal to single-crystal transition from a 7-fold interpenetrated coordination polymer to a non-interpenetrated one by photochemical [2 + 2] polymerization and their sensing properties.

Two complexes, namely [Zn(bpeb)(sda)] (1) and [Zn(poly-bpeb)(sda)] (2), were synthesized by an organic ligand with an extensively conjugated system, bpeb = 1,4-bis[2-(3-pyridyl) vinyl]-benzene, H2sda = sulfonyldibenzoic acid and d10 metal centers Zn2+. Structural analysis revealed that compound 1 was nonporous and possessed 7-fold interpenetrated three-dimensional (3D) frameworks constructed from one-dimensional (1D) Zn-bpeb and Zn-sda chains. Interestingly, due to the short distance between the vinyl groups from two neighboring bpeb ligands, compound 1 could undergo a photochemical [2 + 2] polymerization reaction to generate 2 in a single-crystal to single-crystal (SCSC) manner under the irritation of UV. Moreover, the organic polymer in 2 could be depolymerized by heating to realize the reversible transformation from 2 to 1. Furthermore, both compounds 1 and 2 could be used as fluorescent sensors for 2,4,6-trinitrophenol (TNP) with high selectivity and sensitivity.

RETRACTED: Two co(ii)-Containing coordination polymers: Catalytic dye degradation and anti-cancer activity on the colon cancer cells by regulating the intestinal butyrate production and HDAC2 expression

• Two novel coordination polymers (CPs) were prepared. • Complex 2 can effectively degrade the methylene blue in the water solution under the irradiation of ultraviolet. • The inhibitory effect of compound against the production of intestinal butyrate was evaluated. Through utilizing a mixed-ligand method, two novel coordination polymers (CPs) containing Co(II) of [Co(L)(dcdps)] n ( 1 ) and {Co(L)(bdc)} n ( 2 ) [H 2 bdc = 1,4-dicarboxybenzene; H 2 dcdps = 4,4′-sulfonyldibenzoic acid and L = 4,4′-(2,5-bis(methylthio)-1,4-phenylene)dipyridine] have been prepared by the solvothermal method through Co(NO 3 ) 2 •6H 2 O reacting with the methylthio functionalized dipyridine ligand L in the existence of distinct carboxylic ligands. Compound 2 contains excellent water stability can effectively degrade the methylene blue in the water solution under the irradiation of ultraviolet, which is expected to become a potential photo active material. Furthermore, the inhibitory effect of compound against the production of intestinal butyrate, as well as the HDAC2 expression in colon cancer cells was evaluated. The ELISA test kit was conducted to detect the butyrate content in the intestinal tissue. The real time RT-PCR method was implemented, and the HDAC2 gene relative expression levels in colon cells was measured. Finally, our aim is to generate novel mechanism for the treatment of anti-colon cancer.

Immobilization of a Polar Sulfone Moiety onto the Pore Surface of a Humid-Stable MOF for Highly Efficient CO2 Separation under Dry and Wet Environments through Direct CO2-Sulfone Interactions.

The stability of microporous metal-organic frameworks (MOFs) in moist environments must be taken into consideration for their practical implementations, which has been largely ignored thus far. Herein, we synthesized a new moisture-stable Zn-MOF, {[Zn2(SDB)2(L)2]·2DMA}n, IITKGP-12, by utilizing a bent organic linker 4,4'-sulfonyldibenzoic acid (H2SDB) containing a polar sulfone group (-SO2) and a N, N-donor spacer (L) with a Brunauer-Emmett-Teller surface area of 216 m2 g-1. This material displays greater CO2 adsorption capacity over N2 and CH4 with high IAST selectivity, which is also validated by breakthrough experiments with longer breakthrough times for CO2. Most importantly, the separation performance is largely unaffected in the presence of moisture of simulated flue gas stream. Temperature-programmed desorption (TPD) analysis shows the ease of the regeneration process, and the performance was verified for multiple cycles. In order to understand the structure-function relationship at the atomistic level, grand canonical Monte Carlo (GCMC) calculation was performed, indicating that the primary binding site for CO2 is between the sulfone moieties in IITKGP-12. CO2 is attracted to the bonded structure (V-shape) of the sulfone moieties in a perpendicular fashion, where CCO2 is aligned with S, and the CO2 axis bisects the SO2 axis. Thus, the strategic approach to immobilize the polar sulfone moiety with a high number of inherent stronger M-N coordination and the absence of coordination unsaturation made this MOF potential toward practical CO2 separation applications.

A multifunctional pseudo-polyrotaxane coordination polymer based on the trinuclear cluster [Co3(COO−)4(OH−)2]: Synthesis, structure and properties

A trinuclear cobalt-based multifunctional coordination polymer with a dual loop pseudo-rotaxane motif, namely [Co3(DPFE‧H+)2(sdba2−)4(OH−)2](DPFE‧2H+)(CH3CN) (1), has been synthesized by a mixed ligand strategy under hydrothermal conditions (DPFE = 2,7-di(pyridin-4-yl)-9H-fluorene, H2sdba = 4,4′-sulfonyldibenzoic acid). Compound 1 has 1D + zero-dimensional (0D) → 1D armed pseudo-polyrotaxane character, in which the 1D dual ring chain [Co3(COO−)4(OH−)2(sdba2−)4 is threaded by doubly protonated free DPFE ligands. The trinuclear cobalt cluster and π-electron rich system involving the ligands jointly endow compound 1 with magnetism, photocatalytic and electrochemical properties. Magnetic property measurements of 1 indicate that there exists weak antiferromagnetic coupling in the trinuclear [Co3(COO−)4(OH−)2] unit, the experiments of photocatalytic degradation of dyes demonstrated that 1 has good catalytic activity for the degradation of methylene blue (MB) and the electrochemical results show that compound 1 exhibits a specific capacitance of 52.25 F g−1 at a current density of 1 A g−1 and retains 93.75% specific capacitance after 960 cycles.

A microporous Co(II)-MOF as a pH-responsive 5-Fu delivery system to induce human hemangioma cells apoptosis and abrogate their growth

A microporous metal-organic framework containing Co(II) as nodes with a polar pore surface, {[Co(SDB)(bpdh)0.5]}n (1), was formed via reaction of a –SO2 functionalized organic connector (H2SDB = 4,4′-sulfonyldibenzoic acid) combined with (bpdh = 2,5-bis(3-pyridyl)-3,4-diaza-2,4-hexadiene), N-rich spacer under the solvothermal conditions. The diamond channels of the framework for 1 have a size of 6.1 Å along the b axis of the crystal, and the surface area of BET is 541 m2·g−1. FT-IR spectra demonstrated 5-Fu loading and ultraviolet–visible spectra showed the loading capacity of 5-Fu of 27.36%. Compared with normal tissue of pH = 7.4, the drug release in simulated cancer tissue of pH = 5.7 was gradual, showing a rational pH-responsive drug release. Clone formation experiments and CCK-8 assay confirmed the antitumor activity of 5-Fu@1a against EOMA hemangioma cells. Detection of apoptotic protein level and Annexin V-FITC/PI analysis showed that 5-Fu@1a could induce the apoptosis in caspase-dependent manner. Antitumor ability of the 5-Fu was verified by experimental data in vivo, which is consistent with the experimental data in vitro.

Similar hydrogen-bonded ribbons in three 4,4’-sulfonyldibenzoic anion/boric acid and tetrabutylammonium inclusion compounds

Three novel inclusion compounds of 4,4’-sulfonyldibenzoic anion, boric acid and tetrabutylammonium, 2[(C4H9)4N]+·[C14O6H8S]2−·3.5[B(OH)3]·1.5H2O (1), 2[(C4H9)4N]+·[C14O6H8S]2−·2[B(OH)3]·7H2O (2) and 1.5[(C4H9)4N]+·0.5[C14O6H9S]2−·0.5[C14O6H9S]−·2[B(OH)3] (3), were prepared and characterized by single crystal X-ray diffraction, IR spectroscopy and thermogravimetric analyses (TGA). Compound 1: triclinic system, P¯ 1, a = 9.371(3) Å, b = 17.624(5) Å, c = 18.678(6) Å, α = 92.471(3)°, β = 101.837(4)°, γ = 91.331(4)°, V = 3014.9(15) Å3, Z = 2, R1 = 0.0902; compound 2: orthorhombic, Pca21, a = 19.8104 Å, b = 9.2340 Å, c = 34.9875 Å, V = 6400.2(18) Å3, Z = 4, R1 = 0.0728; compound 3: triclinic, P¯ 1, a = 10.0088(1) Å, b = 13.2179(1) Å, c = 18.945(2) Å, α = 70.6850(1)°, β = 86.9100(1)°, γ = 71.3400(1)°, V = 2237.2(4) Å3, Z = 2, R1 = 0.0628. The results show that the host 4, 4’-sulfonyldibenzoic anion can combine with boric acid to form the similar hydrogen-bonded ribbons through O-H…O interactions in these three compounds. However, with the existence of the same guest template of tetrabutylammonium, the similar ribbons finally generate two sandwich-like layer frameworks of 1 and 2, and one 3D network containing cavities of 3. Clearly, the participation of water molecules should be mainly responsible for the distinct difference between the layer structure and the 3D network.

Two Closely Related Zn(II)-MOFs for Their Large Difference in CO2 Uptake Capacities and Selective CO2 Sorption.

Two azo functionalized Zn(II)-based MOFs, {[Zn(SDB)(3,3'-L)0.5]·xG}n, IITKGP-13A, and {[Zn2(SDB)2(4,4'-L)]·xG}n, IITKGP-13B (IITKGP stands for Indian Institute of Technology Kharagpur), have been constructed through the self-assembly of isomeric N,N'-donor spacers (3,3'-L = 3,3'-azobispyridine and 4,4'-L = 4,4'-azobispyridine) with organic ligand 4,4'-sulfonyldibenzoic acid (SDBH2) and Zn(NO3)2·6H2O (G represents disordered solvent molecules). Single-crystal X-ray diffraction studies reveal the 2D structure with sql topology for both MOFs. However, the subtle change in positions of coordinating N atoms of spacers makes IITKGP-13A noninterpenetrated, while IITKGP-13B bears a 2-fold interpenetrated structure. IITKGP-13A exhibits higher uptake of CO2 over CH4 and N2 with high IAST selectivities for mixed CO2/CH4 (50:50, biogas) and CO2/N2 (15:85, flue gas) gas systems. In contrast, IITKGP-13B takes up very low amount of CO2 gas (0.4 mmol g-1) compared to IITKGP-13A (1.65 mmol g-1) at 295 K. Density functional theory (DFT)-based electronic structure calculations have been performed to explain the origin of the large differences in CO2 uptake capacity between the two MOFs at the atomistic level. The results show that the value of the change in enthalpy (ΔH) at 298 K temperature and 1 bar pressure for the CO2 adsorption is more negative in IITKGP-13A as compared to that in IITKGP-13B, thus indicating that CO2 molecules are more favored to get adsorbed in IITKGP-13A than in IITKGP-13B. The computed values for the Gibbs' free energy change (ΔG) for the CO2 adsorption are positive for both of the MOFs, but a higher value is observed for the IITKGP-13B. The noncovalent types of interactions are the main contribution toward the attractive energies between the host MOF frameworks and guest CO2 molecules, which has been studied with the help of energy decomposition analysis (EDA).

A Pair of CoII Supramolecular Isomers Based on Flexible Bis-Pyridyl-Bis-Amide and Angular Dicarboxylate Ligands.

Thermal reactions of cobalt(II) salts with flexible N,N′-bis(pyrid-3-ylmethyl)adipoamide (L) and angular 4,4′-sulfonyldibenzoic acid (H2SDA) in H2O and CH3OH afforded a pair of supramolecular isomers: [Co2(L)(SDA)2], 1, and [Co2(L)(SDA)2]⋅CH3OH⋅H2O, 2. The structure of complex 1 can be simplified as a one-dimensional (1D) looped chain with L ligands penetrating into the middles of squares, forming a new type of self-catenated net with the (42⋅54)(4)2(5)2 topology, whereas complex 2 displays a 2-fold interpenetrated 2D net with the rare (42⋅68⋅8⋅104)(4)2-2,6L1 topology. While both complexes 1 and 2 display antiferromagnetism with strong spin-orbital coupling, the antiferromagnetism of 2 is accompanied by a cross-over behavior and probably a spin canting phenomenon.

Synthesis, structures, and fluorescence properties of one novel Cobalt metal–organic framework based on a tetraphenylethene-core ligand

A new three-dimensional luminescent cobalt (II) metal–organic framework, [Co(Titpe)(bcpf)·(DMF)]·(H2O)2·(DMF) (compound 1, JUST-8) (Titpe = 1,1,2,2-tetrakis(4-(1H-imidazol-1-yl)phenyl)ethane, bcpf = 4,4′-sulfonyldibenzoic acid; DMF = N, N-dimethylformamide), has been solvothermally synthesized by using CoCl2·6H2O and a mixture of ligands: Titpe ligand and bcpf ligand. Single crystal X-ray analysis reveals that 1 crystallizes in the triclinic system and [Formula: see text] space group with a = 13.2097(14) Å, b = 13.9519(14) Å, c = 14.4413(15) Å, α = 89.949(7)°, β = 70.303(7)°, γ = 80.322(7)°, V = 2465.7(5) Å3, Z = 2, Mr =1032.97, Dc = 1.391 g/cm3, μ = 0.455 mm−1, F(000) = 1070, R = 0.0585, and wR = 0.1540 for 8674 observed reflections ( I &gt; 2σ( I)). Its overall structure is a double-fold interpenetrated framework, and it shows a porosity of 12.97% based on a calculation by PLATON and a 4- c type topological network with the point symbol of {6^5.8}. The Co atom bridges the Titpe ligands to form the one-dimensional chains into a two-dimensional layered structure and then connects the auxiliary ligands to get a three-dimensional structure. Compound 1 showed a blue fluorescence emission with the peak maximum at 431 nm (λex = 314 nm).