5-nitroisophthalic Acid Research Articles

Lanthanide coordination polymers functionalized by 5-nitroisophthalic acid: Synthesis, structure-DFT correlation and photoluminescent sensor of Cd2+ ion

Lanthanide coordination polymers (LnCPs) are influential chemosensors when designed to undergo a detectable change in optical properties upon interacting with target analytes. This work reports interaction of metal ions with LnCPs leading to elicit changes in fluorescence emission intensity, an essential step en route to developing sensitive and selective systems for metal-ion sensing. Towards this goal, solvothermal reaction of 5- Nitroisophthalic Acid (5-NIAH2) and Ln (NO3)3⋅xH2O produced seven Ln-coordination polymers {[Nd (5-NIA) (5-NIAH) (H2O)2]⋅CH3CN}n (1), {[Sm (5-NIA) (5-NIAH) (H2O)2]⋅CH3CN⋅H2O}n (2), {[Gd (5-NIA) (5-NIAH) (H2O)2]⋅(H2O)2}n (3), {[Tb (5-NIA) (5-NIAH) (H2O)2]⋅CH3CN)}n (4), [Dy (5-NIA) (5-NIAH) (H2O)2]n (5), [Ho(5-NIA) (5-NIAH) (H2O)2]n (6) and [Er2 (5-NIA)3(H2O)3(CH3CN)]n (7) with two-dimensional structures. The as-synthesized polymers are characterized by powder X-ray crystallography, infrared spectroscopy, thermogravimetric analysis, photoluminescence and DFT studies. The luminescence properties of [Tb (5-NIA) (5-NIAH) (H2O)2]⋅CH3CN)}n (4) is investigated. The CP-4 is highly sensitive for the detection of Cd2+ exhibiting most intensive fluorescence quenching with the lowest limit of detection. Other metal ions, including Co2+, Fe3+, Fe2+ and Pb2+ are also detected demonstrating the range of sensing capabilities.

Metal-Organic Framework-Based Selective Molecular Recognition of Organic Amines and Fixation of CO2 into Cyclic Carbonates.

Synthesis and structural depiction of two new metal-organic frameworks (MOFs), namely, [{Zn(L)(oba)}·4H2O]α (Zn-MOF-1) and [{Cd1/2(L)1/2(nipa)1/2(H2O)1/2}·(DMF)1/2(H2O)]α (Cd-MOF-2) (where L = N2,N6-di(pyridin-4-yl)naphthalene-2,6-dicarboxamide, 4,4'-H2oba = 4,4'-oxybisbenzoic acid, and 5-H2nipa = 5-nitroisophthalic acid) are reported. Both Zn-MOF-1 and Cd-MOF-2 have been prepared by reacting ligand L and coligand 4,4'-H2oba or 5-H2nipa with the respective dihydrates of Zn(OAc)2 and Cd(OAc)2 (OAc = acetate). Crystal structure X-ray analysis discloses that Zn-MOF-1 displays an overall 2D → 3D interpenetrated framework structure. The topological analysis by ToposPro suggests a (4)-connected uninodal sql topology with a point symbol of {44·62} having 2D + 2D parallel polycatenation. However, crystal packing of Cd-MOF-2 adapted a porous framework architecture and was topologically simplified as (3,4)-connected binodal 2D net. In addition, both Zn-MOF-1 and Cd-MOF-2 were proved to be multifunctional materials for the recognition of organic amines and in the fixation of CO2 to cyclic carbonates. Remarkably, Zn-MOF-1 and Cd-MOF-2 showed very good fluorescence stability in aqueous media and have shown 98 and 97% quenching efficiencies, respectively, for 4-aminobenzoic acid (4-ABA), among all of the researched amines. The mechanistic study of organic amines recognition proposed that fluorescence quenching happened mainly through hydrogen-bonding and π-π stacking interactions. Additionally, cycloaddition of CO2 to epoxide in the presence of Zn-MOF-1 and Cd-MOF-2 afforded up to 96% of cyclic carbonate within 24 h. Both Zn-MOF-1 and Cd-MOF-2 exhibited recyclability for up to five cycles without noticing an appreciable loss in their sensing or catalytic efficiency.

Relative capability demonstration of luminescent Al-MOFs for ideal detection of nitroaromatic explosives.

Here, we have synthesised three luminescent Al MOFs i.e., Al-NTP, Al-FDA, and Al-TDA, using common metal ions (AlCl3·6H2O) with different carboxylic acid organic linkers (5-nitroisophthalic acid, 2,5-furan dicarboxylic acid, and 2,5-thiophenedicarboxylic acid) in a semi-aqueous medium. The structural analysis of Al-MOFs has been confirmed through powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy and absorption spectroscopy. Afterward, the optical properties of all three Al-MOFs were confirmed using photoluminescence spectroscopy and demonstrated for the detection of nitroaromatic explosives. We have observed host-guest interaction through a quenching mechanism. Among the three synthesised Al-MOFs, Al-NTP MOF exhibit 0.014 ppm lowest limit of detection in chloroform at room temperature. Our comparative study results reveal that the selection of the organic linker and solvent plays a critical role in MOF based sensing applications.

Novel Co-crystals and Eutectics of Febuxostat: Characterization, Mechanism of Formation, and Improved Dissolution.

Co-crystallization studies were undertaken to improve the solubility of a highly water-insoluble drug febuxostat (FXT), used in the treatment of gout and hyperuricemia. The selection of co-crystal former (CCF) molecules such as 1-hydroxy 2-naphthoic acid (1H-2NPH), 4-hydroxy benzoic acid (4-HBA), salicylic acid (SAC), 5-nitro isophthalic acid (5-NPH), isonicotinamide (ISNCT), and picolinamide (PICO) was based on the presence of complementary functional groups capable of forming hydrogen bond and the ΔpKa difference between FXT and CCF. A liquid-assisted grinding (LAG) method was successfully employed for the rapid screening of various pharmaceutical adducts. These adducts were characterized based on their unique thermal (differential scanning calorimetry) and spectroscopic (Fourier transform infrared and Raman spectroscopy) profiles. Binary phase diagrams (BPD) were plotted to establish a relationship between the thermal events and adduct formed. Powder X-ray diffraction (PXRD) studies were carried out to confirm the formation of eutectic/co-crystal. Thermogravimetric analysis (TGA) was also performed for the novel co-crystals obtained. The propensity for strong homo-synthons over weak hetero-synthons and strong hetero-synthons over weak homo-synthons during supramolecular growth resulted in the formation of eutectics and co-crystals respectively. FXT:1H-2NPH (1), FXT:4-HBA (1), FXT:SAC (1, 2), and FXT:5-NPH (2-1) gave rise to pure eutectic systems, while FXT:ISNCT (2-1) and FXT:PICO (1) gave rise to novel co-crystals with characteristic DSC heating curves and PXRD pattern. Additionally, the impact of microenvironmental pH and microspeciation profile on the improved dissolution profile of the co-crystals was discussed. Graphical Abstract.

Synthesis, crystal structures, luminescence and magnetic property of two complexes based on 5-nitroisophthalic acid

Synthesis, crystal structures, luminescence and magnetic property of two complexes based on 5-nitroisophthalic acid

A Series of Cobalt-Based Coordination Polymer Crystalline Materials as Highly Sensitive Electrochemical Sensors for Detecting Trace Cr(VI), Fe(III) Ions, and Ascorbic Acid

Convenient, sensitive, and reliable detection of multiple heavy-metal ions is a significant and challenging task with the use of high-yielding and easily synthesized materials. To solve this challenge, five cobalt-based coordination polymers (CPs), [Co2(4-dptb)2(1,3-BDC)2]·2H2O (1), [Co(4-dptb)(5-DIP)] (2), [Co(4-dptb)(5-NIP)] (3), [Co(4-dptb)(5-AIP)] (4), and [Co(4-dptb)(5-MIP)] (5) (4-dptb = N3,N4-bis(pyridin-4-ylmethyl)thiophene-3,4-dicarboxamide, 1,3-BDC = 1,3-benzenedicarboxylate, 5-DIP = 5-hydroxyisophthalic acid, 5-NIP = 5-nitroisophthalic acid, 5-AIP = 5-methylisophthalic acid, 5-MIP = 5-aminoisophthalic acid), have been synthesized by hydrothermal methods. A remarkable electrochemical sensing for Cr(VI) and Fe(III) was confirmed by cyclic voltammetry (CV) and current–time curves (i–t). The results showed that all CPs have a low limit of detection (LOD) of Cr(VI) and Fe(III) and fast electrochemical responses of within 3 s. At the same time, compounds 1–5 have a significant electrocatalytic oxidation effect on ascorbic acid (AA) and can be used as electrochemical sensors for AA.

Nine Supramolecular Adducts of 4-dimethylaminopyridine and Carboxylic acids Assembled by Classical Hydrogen Bonds and Other Noncovalent Intermolecular Interactions

Cocrystallization of the widely available 4-dimethylaminopyridine, with a series of carboxylic acids gave nine molecular adducts 4-dimethylaminopyridinium trifluoroacetate (1), 4-dimethylaminopyridinium glycolate glycolic acid (2), 4-dimethylaminopyridinium 2-furoate dihydrate (3), tri(4-dimethylaminopyridinium) tri(o-chlorobenzoate) tetrahydrate (4), 4-dimethylaminopyridinium 4-bromobenzoate 4-bromobenzoic acid (5), 4-dimethylaminopyridinium 4-formylbenzoate 4-formylbenzoic acid (6), 4-dimethylaminopyridinium 2,4-dichlorobenzoate (7), 4-dimethylaminopyridinium 2-aminobenzoate 2-aminobenzoic acid (8) and bis(4-dimethylaminopyridinium) 5-nitroisophthalate 5-nitroisophthalic acid methanol solvate (9). The nine adducts have been characterised by X-ray diffraction, IR and elemental analysis, the melting points were also reported. Their structural and supramolecular aspects are fully analyzed.The result reveals that among the nine investigated crystals only the ring Ns in the 4-dimethylaminopyridine moieties are protonated when the carboxylic acids are deprotonated. The crystal packing is interpreted by the strong charge-assisted N-H⋯O hydrogen bond between the NH+ and the deprotonated acidic groups. Except the N-H⋯O hydrogen bonds, the charge assisted or neutral O-H···O hydrogen bonds were also found at 2-6, 8 and 9. The COOH···COO−synthon has been at 2, 5-6 and 8-9.Further analysis of the crystal packing indicated that a different family of additional CH-O/CH2-O/CH3-O, F-F, Br-Br, CH-Cl, CH3-Cl, CH-π/CH3-π, C-H···Cπ, C-π, Cl-O, O-C, O-π and π-π contacts contribute to the stabilization and expansion of the total high-dimensional (2D-3D) framework structures. For the synergism of the various nonbonding contacts there created homo/hetero supramolecular synthons or both.

Synthesis and characterization of three co-crystals of bis(benzimidazole) derivatives with aromatic dicarboxylic acids

Combination of three aromatic carboxylic acids (5-nitroisophthalic acid (H2nip), 2,6-naphthalenedicarboxylic acid (H2ndc), tetrabromoterephthalic acid (H2tbta)) and flexible bis(benzimidazole) derivatives (1,6-bis(2-methylbenzimidazol-1-yl)hexane (L1), 1,2-bis(2-methylbenzimidazol-1-ylmethyl)benzene (L2), 1,4-bis(2-methylbenzimidazol-1-yl)butane (L3)), three co-crystals [(H2L1)2+·2(Hnip)−·H2O] (1), [(L2)·(H2ndc)] (2) and [(H2L3)2+·(tbta)2−] (3) were synthesized hydrothermally. Single-crystal X-ray diffraction, elemental analysis and IR spectra are employed to characterize 1, 2 and 3. The 2D fingerprint plots and Hirshfeld surfaces of 1, 2 and 3 indicate that the 3D supramolecular network for 1 was generated by N–H···O, O–H···O, C–H··O hydrogen bonds and π−π interactions, the 2D sheet for 2 was produced by O–H···N hydrogen bonds and π−π interactions, and C–H···O hydrogen bonds make structures more stable. For 3, the 2D supramolecular layer was yielded by N–H···O, C–H···O hydrogen bond interactions. Furthermore, thermogravimetric analyses and photoluminescence properties of three compounds were presented.

NO2 Removal under Ambient Conditions by Nanoporous Multivariate Zirconium-Based Metal–Organic Framework

Zirconium-based metal–organic frameworks (Zr-MOFs) have attracted tremendous attention as promising candidates for removing toxic chemicals under ambient conditions in virtue of their remarkable thermal, mechanical, and chemical stability. Here, we demonstrate for the first time the enhanced performance of nanoporous dicarboxylic acid-functionalized MOF-808 analogues toward NO2 removal under both dry and moist conditions. Based on a pKa-directed solvent-assisted ligand exchange (SALE) strategy, a series of dicarboxylic acid ligands, including isophthalic acid, 5-hydroxyisophthalic acid, 5-aminoisophthalic acid, 5-nitroisophthalic acid, and pyridine-3,5-dicarboxylic acid, were precisely incorporated into the MOF-808 framework via substitution of formate ligands. The assembled MOF-808 derivatives demonstrated good crystallinity, well-defined morphology, high porosities, and tunable dicarboxylic acid contents, with the maximum molar ratios of dicarboxylic acid ligands to 1,3,5-benzenetricarboxylic acids in frameworks larger than 1:1. The microbreakthrough tests showed that the 5-aminoisophthalic acid-modified MOF-808 (808-NH2IPA) exhibited a significant enhancement in NO2 capacities and the most remarkable reduction in the release of toxic NO byproduct as compared to pristine MOF-808. Detailed removal mechanisms for NO2 were developed on the basis of multiple ex-situ characterization techniques and in-situ infrared Fourier transform spectroscopy. The effects of humidity on the mechanisms were also discussed. The reactions between the amino groups and NOx, yielding nitramines, nitrosamines, and arenediazonium salts, were proposed to play a major role for the outstanding performance of 808-NH2IPA for dry NO2 removal. The acid–base reaction between HNO3 and the amino groups preponderated in the moist NO2 removal process, with the anilinium nitrate species turning into the principal product.

Two diverse temperature-directed cobalt-based coordination polymers: environmentally friendly photocatalysts for degradation of organic dyes

Two new cobalt-based coordination polymers (CPs) based on a semirigid naphthalene-bridged bis-pyridyl-bis-amide ligand, namely [Co(4-bmnpd)(5-HNIP)2(H2O)2] (1) and [Co4(4-bmnpd)4(5-NIP)4]·2H2O (2) (4-bmnpd = N,N′-bis(4-methylenepyridin-4-yl)-2,6-naphthalenedicarboxamide, 5-H2NIP = 5-nitroisophthalic acid), have been prepared under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses, infrared (IR) spectroscopy, and powder X-ray diffraction (PXRD). The structural analyses show that 1 has a one-dimensional (1D) chain structure while 2 exhibits a two-dimensional (2D) network. The effect of temperature on the structures of the CPs is discussed. The solid-state fluorescent properties of 1 and 2 were determined at room temperature. Furthermore, their photocatalytic degradation properties were also studied. Photocatalysts 1 and 2 are environmentally friendly and can effectively degrade organic dye Congo Red (CR) under ultraviolet (UV) light. In addition, the possible degradation mechanism was also investigated.

Two luminescent Ni(II) coordination polymers for sensing of iron(III) ions/benzaldehyde and photocatalytic degradation of methylene blue under UV irradiation

Two nickel(II) coordination polymers (CPs), [Ni(5-NIP)(L)(H2O)]n (1) and [Ni(1,4-PDA)(L)(H2O)]n (2) (L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)propane, 5-H2NIP = 5-nitroisophthalic acid, 1,4-H2PDA = 1,4-phenylenediacetic acid) were hydrothermally synthesized and structurally characterized. 1 displays a 1D zigzag chain alone the a-axis. 2 shows a 3,5-connected 3,5L27 framework with a point symbol of {3.4.5}{32.42.5.63.72}. Two compounds exhibit remarkable photocatalytic activities for degradation of the methylene blue under UV irradiation. 1 and 2 can serve as the dual-responsive luminescent chemosensors for the selective detection of benzaldehyde and Fe3+ in aqueous systems.

A new Cd-based metal organic framework derived nitrogen doped nano-porous carbon for high supercapacitor performance

A new cadmium metal–organic framework [Cd(NIPA)(CH3CH2OH)3] (NIPA = 5-nitroisophthalic acid) has been assembled and served as precursor to fabricate nanoporous nitrogen doped carbon material via carbonization process under 900 °C (NC900). The obtained NC900 shows high capacitance (367 F g−1 at 1 A/g), good cycling life (95% of initial capacitance after 3000 cycles). Moreover, NC900//NC900 supercapacitor device is assembled and shows energy density of 6.3 Wh kg−1 with a current density of 1 A/g and the capacitance retention maintains 65% at 0.5 A g−1 after 3000 cycles). The results obtained provide a facile way to prepare carbon material (MOF is used as precursor) for energy-storage devices. For the first time, the heteroatom doped nanoporous carbon material based on a new Cd MOF is served as supercapacitor materials.

Three Different Co(II) Metal–Organic Frameworks Based on 4,4′-Bis(imidazolyl)diphenyl Ether: Syntheses, Crystal Structure and Photocatalytic Properties

Three Co(II) metal–organic frameworks (Co-MOFs) build by 4,4′-bis(imidazolyl)diphenyl ether (bidpe), m-Phthalic acid (H2mpa), 5-Nitroisophthalic acid (H2nmpa) and 5-sulfonatobenzene-1,3-dicarboxylate (H2smpa), namely: [Co(mpa)(bidpe)]n (1), [Co(nmpa)(bidpe)]n (2), {[Co1.5(smpa)(bidpe)2]·1.5H2O·0.25DMA}n (3), were synthesized under same solvothermal condition. The compounds have been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, thermogravimetric (TG) analysis and powder X-ray diffraction (PXRD). The single-crystal X-ray diffraction analysis reveals that compound 1 shows a 4-connected sql net with Schlafli point symbol (44·62). Compound 2 displays a 3, 5-connected net with Schlafli point symbol (42·67·8)(42·6). Compound 3 possesses a 3-connected net with Schlafli point symbol (42·6). The photocatalytic investigations indicate that compounds 1–3 afford good photocatalytic capabilities in degradation of methylene blue (MB) and methylene violet (MV). Furthermore, the possible photocatalytic mechanisms have been discussed.

Bifunctional chemosensor based on a dye-encapsulated metal-organic framework for highly selective and sensitive detection of Cr2O72− and Fe3+ ions

A three-dimensional protonated proflavin (PF) encapsulated metal-organic framework, formulated as [Zn(NIPH)2(HPF)2] (1), has been successfully synthesized under hydrothermal conditions using the familiar and cheap ligand 5-nitroisophthalic acid (5-H2NIPH). The as-synthesized compound 1 exhibits an intense green emission in solution, whereas strong red fluorescence is observed in the crystal form. The strong green emission of 1 could be highly and selectively quenched by Fe3+ ions, even in the presence of other competing metal ions such as Ag+, Al3+, Ca2+, Cd2+, Co2+, K+, Mg2+, Mn2+, Na+ and Zn2+. In addition, 1 exhibits superior selectivity and sensitivity towards Cr2O72− ions over other anions including Br−, CH3COO−, Cl−, F−, H2PO4−, HCO3−, HPO42−, NO3−, PO43− and SO42−. The possible luminescence quenching mechanisms were investigated. This work revealed that a dye-encapsulated MOF can be used as one of the most fascinating multi-response luminescence materials for selective chemical sensing.

Three isostructural Zn/Ni nitro-containing metal-organic frameworks for supercapacitor

As a novel composite material, metal-organic frameworks have a great application in supercapacitor. In the current study, based on mixed ligands of 5-nitroisophthalic acid (H2NIPA) and 1,3-di(4-pyridyl)propane (1,3-dpp), [Zn3(NIPA)3(1,3-dpp)(H2O)2·H2O]nHU14 and two isostructural [M(NIPA)(1,3-dpp)(H2O)·2H2O] (M ​= ​Zn for HU15, M ​= ​Ni for HU16) were prepared by hydrothermal reaction. The single crystal X-ray diffraction determined that HU14 contains three different zinc ions to construct a non-porous 3D network, while the isostructure HU15 and HU16 display different center metal ions but identical porous frameworks with large brick-like channels. Due to different cations and diverse architectures, these three materials show different electrochemical properties, Ni-MOF(HU16) displays a better performance (The specific capacitance of the complexes HU14, HU15 and HU16 are 22.8 ​F ​g−1, 27.86 ​F ​g−1 and 307.4 ​F ​g−1 at 1 ​A ​g−1 and remains 60.35%,71.79% and 51% of their capacitance at a high current density of 8 ​A ​g−1, respectively.) The excellent electrochemical property may be ascribed to the intrinsic nature of Ni-MOF, unique structural feature and the particles of nanoscale size.

Electrically conductive Cu(II)-based 1D coordination polymer with theoretical insight.

A nitro-functionalized Cu(ii)-based one-dimensional coordination polymer (1D CP) [Cu(nip)(4-phpy)2]n (1) (H2nip = 5-nitroisophthalic acid and 4-phpy = 4-phenylpyridine) was synthesized and characterized by elemental analysis, powder X-ray diffraction (PXRD) and single crystal X-ray diffraction (SCXRD). In the solid-state self-assembly of 1, two sets of weak intermolecular forces, CHπ interaction among the axially bound 4-phpy ligands and ππ interaction among bridging nip ligands from adjacent 1D coordination polymeric chains led to 3D supramolecular packing. Interestingly compound 1 exhibited electrical conductivity in the semiconducting regime and behaved as a Schottky barrier diode.

Studies on Magnetic and Dielectric Properties of Antiferromagnetically Coupled Dinuclear Cu(II) in a One-Dimensional Cu(II) Coordination Polymer.

A one-dimensional Cu(II) coordination polymer with encapsulated antiferromagnetically coupled binuclear Cu(II) has been synthesized by using 5-nitroisophthalic acid (5-N-IPA) and 4-aminopyridine (4-APY) [Cu2(5-N-IPA)2(4-APY)4]n (1). Electrical properties are examined by complex impedance (Z*), dielectric permittivity (ε*), and ac conductivity studies at different frequencies (10 kHz–5 MHz) and temperatures (253–333 K). The contribution of grain and grain boundary has been explained by a different theoretical model. The variable temperature magnetic susceptibility data for compound 1 were recorded between 300 and 2 K. The shape of the curve (χMT vs T) indicates dominant antiferromagnetic coupling, which results from the interaction between the copper(II) atoms.

Multiple strong hydrogen bonded supramolecular cocrystals of 18-crown-6 with 5-nitroisophthalic acid: Solvent effect and optical nonlinearities

Novel cocrystals of 18-crown-6 (18C6) with 5-nitroisophthalic acid (5NIPA) have been prepared by reaction in a solution of CH3OH–H2O (2:3, v/v) and C2H5OH–H2O (2:3, v/v) systems. The cocrystals 18-crown-6.5-nitroisophthalic acid. CH3OH.2(H2O) (I) and 18-crown-6.5-nitroisophthalic acid.3(H2O) (II) have been characterized by X-ray diffraction and constructed supramolecular assembly is thoroughly investigated. CH3OH incorporation inducing centrosymmetric crystallization and acentric crystal packed supramolecular construction in presence of ethanol are the highlights of the study. Intermolecular interactions are quantified by Hirshfeld surface analysis. First-order molecular hyperpolarizability estimated by theoretical calculations indicate a significant microlevel nonlinearity in both cases and Z-scan studies suggest a promising third-order nonlinear optical behaviour. Supramolecular assembly afford multiple strong O–H ….O hydrogen bonds creating a facile atmosphere for optical nonlinearity and mainly these O ….O hydrogen bonds stabilize the structure.

Luminescent Pr(III)-Based Coordination Polymer: Syntheses, Structures, N2 and CO2 Adsorption Properties

A new Pr(III)-based metal organic framework with formula {[Pr2(C8H3O6N)(SO4)2]·5H2O}n was hydrothermally synthesized and characterized by techniques of single crystal X-ray diffraction, infrared spectra (IR), thermogravimetric analysis (TGA), elemental analysis, powder X-ray diffraction (PXRD), and luminescent measurements. X-ray crystal structure analyses reveal that complex 1 is binuclear structure and all Pr(III) atoms show a coordination number of nine with a tricapped trigonal prismatic coordination geometry. Throughout the molecular structure, this lanthanide metal–organic frameworks exhibits a 3D architecture built by the 1D double-stranded chains of Pr ions linked by the 5-nitroisophthalic acid ligand and 2D Pr–SO42− grid. In addition, the fluorescence, nitrogen adsorption properties and carbon dioxide adsorption properties of complex 1 were also investigated. The results indicate that the complex is not only a luminescent and mesoporous material, but also a potential material for selective absorption of carbon dioxide.

Crystal structures and thermal decomposition kinetics of three new Zn(II) coordination polymers based on 3-amino-1,2,4-triazole

Solvothermal reactions of Zn(NO3)2·6H2O, 3-amino-1,2,4-triazole as well as three different carboxylate ligands afforded three novel coordination polymers: [Zn2 (azdc) (atz) (OH) (H2O)]n (1), {[Zn1.5 (btc)0.5 (atz)]·1.5H2O}n (2), and {[Zn4 (nipa)2 (atz)3(OH) (H2O)]·2H2O}n (3) (H2azdc = 4,4′-azobenzoic acid, H4btc = 1,2,4,5-benzenetetracarboxylic acid, 5-H2nipa = 5-nitroisophthalic acid, Hatz = 3-amino-1,2,4-triazole). Moreover, the three coordination polymers have been characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction, and powder X-ray diffraction techniques. Complex 1 reveals a 2D layer structure, which is further connected through π–π stacking interactions forming a 3D supramolecular network. Complex 2 exhibits a 3D porous framework with 1D open channels. Complex 3 shows a 3D pillared-layer framework. Notably, the thermal decomposition processes of 1–3 were investigated by simultaneous TG−DSC techniques. The TG curves reveal that complexes 1–3 possess pretty good thermostability up to 321 °C, 416 °C and 418 °C, respectively. The apparent activation energy E (E1 = 194.975 kJ mol−1, E2 = 220.360 kJ mol−1, E3 = 223.600 kJ mol−1) and the pre-exponential factor A of skeleton collapse for the complexes 1–3 were calculated by the integral Kissinger's method and Ozawa−Doyle's method. The structural stability could be illustrated from the point of thermal decomposition kinetics.