Isophthalic Acid Research Articles

One Co-MOF with F Active Sites for Separation of C2H2 from CO2, C2H4, and CH4.

Separating acetylene (C2H2) from other light hydrocarbons and carbon dioxide (CO2) mixtures under mild conditions poses significant challenges due to the remarkably similar properties between C2H2 and those gases. For the goal of C2H2 separation, a F-functionalized organic linker, H2F-PyIP = 2-fluorine-5-(4-pyridyl)isophthalic acid, was designed, and the corresponding metal-organic framework (MOF), {[Co2(F-PyIP)2DMF]·4H2O}n (1), was constructed. The MOF with open channels decorated by the active sites of the F groups revealed the exceptional C2H2 uptake and selectivity over CO2, C2H4, and CH4. The breakthrough experiments with different molar ratios of C2H2-C2H4, C2H2-CO2, and other gas mixtures further verified superior separation capacity of the MOF. In particular, the dynamic separation time intervals for gas mixtures (C2H2/CO2 = 1:1, 1:5, 1:10, and 1:20) fell in the range 30-44 min, highlighting the potential of the MOF for tackling the challenging C2H2/CO2 separation process.

Introducing free carboxylic acid groups along polyester chains using dimethylolpropionic acid as diol component

While different biodegradable polyesters have already been developed as green alternatives in food packaging, replacing functional polymers as present for example in superabsorbers is more complex due to the lack of selectivity in industrial polyester production. In this work, the trifunctional dimethylolpropionic acid (DMPA) was shown to react selectively as a diol component choosing the right reaction partners, introducing free carboxylic acid groups along the polyester chain. The reaction behavior was thoroughly investigated using a multimethod approach including NMR spectroscopy, MALDI mass spectrometry, and HPLC-MS. While reaction with adipic acid and 1,4-cyclohexanedicarboxylic acid was successful, material properties were inferior due to glass transition temperatures of the resulting polymers below 20 °C. A significant increase of Tg values up to 50 °C was obtained by introducing the aromatic isophthalic acid which could however not be realized in a direct reaction. Instead, a precondensate of isophthalic acid and neopentyl glycol was synthesized followed by the simultaneous addition of DMPA and the (cyclo)aliphatic acids. This protocol and the detailed description of characterization methods allow further investigations of DMPA polyester systems which carry potential in the fields of drug delivery, hydrogels, and superabsorbers as well as coatings, dispersants, and waste water treatment.

Investigation of migrants from can coatings: Occurrence in canned foodstuffs and exposure assessment

In the present study migrants from can coatings, specifically epoxy and polyester resins, were determined in canned foods. Targeted and non-targeted approaches were applied to explore the migrating compounds. Bisphenol A (BPA), BADGE .2 H2O, BADGE·H2O.HCl and cyclodiBADGE from epoxy resins and three monomers i.e., terephthalic acid (TPA), phthalic acid (PA), isophthalic acid (IPA) and four tentatively identified oligomers from polyester resins were found in the foodstuffs. Using the consumption data from the Spanish consumption survey, dietary exposure to these chemicals was assessed. Mainly, our data suggested low exposure to the migrants evaluated, however, it is important to highlight that cyclic oligomers showed the highest mean exposure (0.00646–2.75 μg/kg bw/day) and these molecules belong to Cramer class III, which means that they may have significant toxicity.

Highly Water-Stable Zinc Based Metal-Organic Framework: Antibacterial, Photocatalytic Degradation and Photoelectric Responses.

A reported water-stable Zn-MOF ([Zn(L)2(bpa)(H2O)2]·2H2O, H2L = 5-(2-cyanophenoxy) isophthalic acid has been prepared via a low-cost, general and efficient hydrothermal method. It is worth noting the structural features of Zn-MOF which exhibit the unsaturated metal site and the main non-covalent interactions including O⋯H, N⋯H and π-π stacking interactions, which lead to strong antibacterial and good tetracycline degradation ability. The average diameter of the Zn-MOF inhibition zone against Escherichia coli and Staphylococcus aureus was 12.22 mm and 10.10 mm, respectively. Further, the water-stable Zn-MOF can be employed as the effective photocatalyst for the photodegradation of tetracycline, achieving results of 67% within 50 min, and it has good cyclic stability. In addition, the photodegradation mechanism was studied using UV-vis diffuse reflection spectroscopy (UV-VIS DRS) and valence-band X-ray photoelectron spectroscopy (VB-XPS) combined with the ESR profile of Zn-MOF, which suggest that ·O2- is the main active species responsible for tetracycline photodegradation. Also, the photoelectric measurement results show that Zn-MOF has a good photocurrent generation performance under light. This provides us with a new perspective to investigate Zn-MOF materials as a suitable multifunctional platform for future environmental improvement applications.

Modulating Ligand-Exchange Dynamics on Metal-Organic Polyhedra for Reversible Sorting and Hybridization of Miktoarm Star Polymers.

The precise synthesis of miktoarm star polymers (MSPs) remains one of the great challenges in synthetic chemistry due to the difficulty in locating appropriate structural templates and polymer grafting/growing strategies with high selectivity and efficiency. Herein, ≈2 nm metal-organic polyhedra (MOPs), constructed from the coordination of isophthalic acid (IPA) and Cu2+ , are applied as templates for the precise synthesis of 24-arm MSPs for their unique logarithmic ligand-exchange dynamics. Six different polymers are prepared with IPA as an end group and they further coordinated with Cu2+ to afford the corresponding 24-arm star homo-polymers. MSPs can be obtained by mixing targeted homo-arm star polymers in solutions upon thermal annealing. The compositions of MSPs can be facilely and precisely tuned by the recipe of the star polymer mixtures used. Interestingly, the obtained MSPs can be sorted into homo-arm star polymers through a typical solvent extraction procedure. The hybridization and sorting process can be reversibly conducted through the cycle of thermal annealing and solvent treatment. The complex coordination framework not only opens new avenues for the facile and precise synthesis of MSPs and MOPs with hybrid functionalities, but also provides the capability to design sustainable polymer systems.

Modulating Ligand‐Exchange Dynamics on Metal‐Organic Polyhedra for Reversible Sorting and Hybridization of Miktoarm Star Polymers

AbstractThe precise synthesis of miktoarm star polymers (MSPs) remains one of the great challenges in synthetic chemistry due to the difficulty in locating appropriate structural templates and polymer grafting/growing strategies with high selectivity and efficiency. Herein, ≈2 nm metal‐organic polyhedra (MOPs), constructed from the coordination of isophthalic acid (IPA) and Cu2+, are applied as templates for the precise synthesis of 24‐arm MSPs for their unique logarithmic ligand‐exchange dynamics. Six different polymers are prepared with IPA as an end group and they further coordinated with Cu2+ to afford the corresponding 24‐arm star homo‐polymers. MSPs can be obtained by mixing targeted homo‐arm star polymers in solutions upon thermal annealing. The compositions of MSPs can be facilely and precisely tuned by the recipe of the star polymer mixtures used. Interestingly, the obtained MSPs can be sorted into homo‐arm star polymers through a typical solvent extraction procedure. The hybridization and sorting process can be reversibly conducted through the cycle of thermal annealing and solvent treatment. The complex coordination framework not only opens new avenues for the facile and precise synthesis of MSPs and MOPs with hybrid functionalities, but also provides the capability to design sustainable polymer systems.

Synthesis, characterization, and spectroscopic analysis of binuclear tungsten(VI) complexes with peroxidase-like activity

Two novel binuclear tungsten(VI) complexes, denoted as 1 and 2, encompasing oxidoperoxido- and dioxido- moieties, have been successfully synthesized and investigated. These complexes, namely [{WO(O2)}2(L)(H2O)2] 1, and [{WO2}2(L)(H2O)2] 2, are formed utilizing the ligand H4L I, obtained through the condensation reaction of 2-hydroxyacetophenone and dihydrazide of isophthalic acid in a 2:1 ratio. The synthetic route for complex 1 entails an in-situ reaction between WO3·H2O and H2O2, executed alongside the ligand in a stoichiometric ratio of 1:2. On the other hand, the synthesis of complex 2 involves the reaction of complex 1 with triphenylphosphine. The synthesized compounds underwent comprehensive analytical investigation through elemental (CHN) analysis, spectroscopic techniques (FT-IR, UV–Vis, 1H, and 13C NMR), and thermal analysis (TGA). Density functional theory (DFT) computations were employed to calculate vibrational frequencies and NMR parameters for both the ligand and the corresponding tungsten complexes. Encouragingly, upon a comparison of the theoretical and experimental data, a remarkable congruence was observed. Furthermore, these complexes displayed noteworthy peroxidase-like activity when subjected to hydrogen peroxide, as evidenced by their catalytic oxidation of dopamine.

Updated Abraham model correlations for describing solute transfer into both 2-Pentanol and 3-Methyl-1-butanol based on much larger data sets

ABSTRACT Mole fraction solubilities of 4-tert-butylbenzoic acid, 3-chlorobenzoic acid, 2-methyl-3-nitrobenzoic acid, 3-methyl-4-nitrobenzoic acid, 3,4,5-trimethoxybenzoic acid, isophthalic acid, 3-hydroxybenzoic acid, o-acetoacetaniside, 2,4-dihydroxybenzophenone, benzoin, paracetamol, and 1,4-dichloro-2-nitrobenzene in 2-pentanol at 298.15 K. Results of the experimental measurements, combined with published literature data, were used to calculated revised equation coefficients for the Abraham model correlations for the 2-pentanol solvent. Revised equation coefficients are also reported for the 3-methyl-1-butanol Abraham model correlations based on much larger data sets containing 95 experimental data points.

The Effect of Pendent Groups upon Flexibility in Coordination Networks with Square Lattice Topology.

Gas or vapor-induced phase transformations in flexible coordination networks (CNs) offer the potential to exceed the performance of their rigid counterparts for separation and storage applications. However, whereas ligand modification has been used to alter the properties of such stimulus-responsive materials, they remain understudied compared with their rigid counterparts. Here, we report that a family of Zn2+ CNs with square lattice (sql) topology, differing only through the substituents attached to a linker, exhibit variable flexibility. Structural and CO2 sorption studies on the sql networks, [Zn(5-Ria)(bphy)]n, ia = isophthalic acid, bphy = 1,2-bis(pyridin-4-yl)hydrazine, R = -CH3, -OCH3, -C(CH3)3, -N=N-Ph, and -N=N-Ph(CH3)2, 2-6, respectively, revealed that the substituent moieties influenced both structural and gas sorption properties. Whereas 2-3 exhibited rigidity, 4, 5, and 6 exhibited reversible transformation from small pore to large pore phases. Overall, the insight into the profound effect of pendent moieties of linkers upon phase transformations in this family of layered CNs should be transferable to other CN classes.

Dual-Emitting Mixed-Lanthanide Metal-Organic Framework for Ratiometric and Quantitative Visual Detection of 2,6-Pyridine Dicarboxylic Acid.

The detection of the major biomarker of Bacillus anthracis, 2,6-dipicolinic acid (DPA), has attracted great interest in recent years. In this work, mixed-lanthanide metal-organic frameworks (M'LnMOFs), TbxEu1-x-cppa (cppa = 5-(5-carboxypyridin-3-yl)isophthalic acid), with different Tb/Eu ratios, were solvothermally synthesized. The results reveal that ratiometric fluorescent probe [Tb0.533Eu0.467-(Hcppa)1.5(H2O)(DMF)]·3H2O is water and acid-base stable and exhibits excellent sensitivity (LOD = 2.286 μM), high selectivity, and fast response (<2 min) for the detection of DPA. Due to the blocked energy transfer from Tb3+ to Eu3+ and the inner filter effect upon the addition of DPA, the fluorescent probe shows a distinct color change from orange-red to green. Furthermore, the visual detection of DPA was realized by identifying the RGB values of MOF-based agarose hydrogel films via a smartphone, highlighting the practical application of the fluorescent probe for DPA detection under aqueous solution conditions.

Two-Dimensional Lanthanide Metal-Organic Frameworks as a Platform for Sensing Pollutant and Nitrophenols Reduction.

The discharge of harmful and toxic pollutants in water is destroying the ecosystem balance and human being health at an alarming rate. Therefore, the detection and removal of water pollutants by using stable and efficient materials are significant but challenging. Herein, three novel lanthanide metal-organic frameworks (Ln-MOFs), [La(L)(DMF)2(H2O)2]·H2O (LCUH-104), [Nd(L)(DMF)2(H2O)2]·H2O (LCUH-105), and [Pr(L)(DMF)2(H2O)2]·H2O (LCUH-106) [H3L = 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid (H3TZI)] were solvothermally constructed and structurally characterized. In the three Ln-MOFs, dinuclear metallic clusters {Ln2} were connected by deprotonated tetrazol-containing dicarboxylate TZI3- to obtain a 2D layered framework with a point symbol of {42·84}·{46}. Their excellent chemical and thermal stabilities were beneficial to carry out fluorescence sensing and achieve the catalytic nitrophenols (NPs) reduction. Especially, the incorporation of the nitrogen-rich tetrazole ring into their 2D layered frameworks enables the fabrication of Pd nanocatalysts (Pd NPs@LCUH-104/105/106) and have dramatically enhanced catalytic activity by using the unique metal-support interactions between three Ln-MOFs and the encapsulating palladium nanoparticles (Pd NPs). Specifically, the reduction of NPs (2-NP, 3-NP, and 4-NP) in aqueous solution by Pd NPs@LCUH-104 exhibits exceptional conversion efficiency, remarkable rate constants (k), and outstanding cycling stability. The catalytic rate of Pd NPs@LCUH-104 for 4-NP is nearly 8.5 times more than that of Pd/C (wt 5%) and its turnover frequency value is 0.051 s-1, which indicate its excellent catalytic activity. Meanwhile, LCUH-105, as a multifunctional fluorescence sensor, exhibited excellent fluorescence detection of norfloxacin (NFX) (turn on) and Cr2O72- (turn off) with high selectivity and sensitivity at a low concentration, and the corresponding fluorescence enhancement/quenching mechanism has also been systematically investigated through various detection means and theoretical calculations.

2,5-Tetrahydrofurandimethanol as a sustainable comonomer for modification of polyethylene terephthalate: Liter-level pilot test and non-isothermal crystallization kinetics

2,5-tetrahydrofurandimethanol (THFDM), which is an alicyclic diol in products of 5-hydroxymethylfurfural (HMF), is a sustainable monomer to protect environment for replacing the role of isophthalic acid (IPA) and 1,4-cyclohexanedimethanol (CHDM) which were optimized polyethylene terephthalate (PET) performance. By direct esterification method, poly (ethylene-co-tetrahydrofurandimethanol terephthalate) (PETT) was synthesized in 2.5 L reactor. The results showed that the contents of THFDM in copolyester were less than that feeding ratio attributed to its lower reaction reactivity. The color of PETT slightly turned yellow. PETT performed broader processing temperature window, while Tg maintained in good range because of the cyclic structure of THFDM. Especially, the cold crystallization occured in PETT but not in PET after finishing melt crystallization. Otherwise, the thermal stability and crystal structure of PETT remained the same as PET. The crystallization activity of PETT became significantly lower than PET. What proved THFDM was effective in reducing PET crystallinity was that crystallization kinetics using Jeziorny theory and the trend of activation energy of melt crystallization which was calculated by Friedman method. And PETT-2 fibre had comparable mechanical property to PET fibre. In the advancement of green chemistry, THFDM has added a choice of cyclic bio-based comonomers.

Determination of the solubility profile of isophthalic acid in some aqueous solutions of betaine-based deep eutectic solvents: Study the extent of H-bonding interactions between starting materials of deep eutectic solvents in aqueous medium

The equilibrium solubility of isophthalic acid (IPA) in three aqueous solutions of betaine/propylene glycol (Bet/PG, 1:5 M ratio), betaine/ethylene glycol (Bet/EG, 1:3 M ratio) and betaine/glycerol (Bet/Gly, 1:3 M ratio) deep eutectic solvents (DESs) (1) was determined experimentally by utilizing a shake-flask method at 293.15–313.15 K covering the whole composition range at atmospheric pressure (≈85 kPa). For three investigated systems, an increase in solubility was observed by decreasing water mass fraction; so that, the lowest and highest solubilities were in water at 293.15 K and pure DESs at 323.15 K, respectively. Also, the mixtures containing PG presented the higher values of the solubility than that of EG or Gly which may be attributed to its lower dipole moment and dielectric constant (2.27 D, 32.0) than the others. By representation the derived equilibrium solubilities with models of Jouyban-Acree, Jouyban-Acree-van't Hoff, NRTL and Wilson a maximum overall mean relative deviation of 15.9% was achieved. Moreover, the solubilities of IPA in ternary (Bet + PG, EG or Gly + water) mixtures at 298.15 were measured to investigate the extent of H-bonding interactions of Bet with PG, EG or Gly into DESs in the presence of water by comparing IPA solubility data for each binary (DES + water) system and the corresponding ternary mixtures. The results suggested that the H-bonding interactions between two components of DESs were disappeared when the water content was exceeded 60% (g/g). This result more explored by recording 1H NMR spectra of diluted DESs with deuterium dioxide. Eventually, an endothermic and enthalpy-driven process in most mixtures was determined by thermodynamic analysis of IPA dissolution and mixing processes based on the modified van't Hoff equation.

Constructed CdS/Mn-MOF heterostructure for promoting photocatalytic degradation of Rhodamine B

A new 3D Mn-MOF was prepared with the ligand H2L (H2L = 5-(pyrazin-2-yl) isophthalic acid) by solvothermal method. Then the Mn-MOF was used as a precursor to synthesize CdS/Mn-MOF composites. The degradation efficiency of Rhodamine B (RhB) by CdS/Mn-MOF (theoretical mass ratio of CdS to Mn-MOF is 1:1) is 98.7% in 60 min, which is 19.7 times and 2.3 times that of Mn-MOF and CdS, respectively. The outstanding performance is owed to the loading of CdS, which significantly broadens the photoresponsive range of Mn-MOF and improves the utilization of visible light. Meanwhile, the heterojunction formed between Mn-MOF and CdS can effectively inhibit the recombination of photogenerated electrons and holes. Furthermore, the photocurrent intensity of CdS/Mn-MOF(50) is higher than that of Mn-MOF and CdS. The photocatalytic performance of CdS/Mn-MOF(50) also exhibits excellent stability and reusability. In addition, the enhanced mechanism of photocatalytic activity was investigated systematically.

Enhancement of Hydrogen Adsorption on Spray-Synthesized HKUST-1 via Lithium Doping and Defect Creation.

We prepared HKUST-1 (Cu3BTC2; BTC3- = 1,3,5-benzenetricarboxylate) using a spray synthesis method with Li doping and defect created via partial replacement of H3BTC with isophthalic acid (IP) to enhance the H2 adsorption capacity. Li-doping was performed by incorporating LiNO3 in HKUST-1 via spray synthesis and subsequent thermal treatment for decomposing NO3-, which enhances H2 uptake at 77 K and 1 bar per unit mass and per unit area from 2.37 wt% and 4.16 molecules/nm2 for undoped HKUST-1 to 2.47 wt% and 4.33 molecules/nm2, respectively. Defect creation via the replacement of the BTC3- linker with the IP2- linker slightly in HKUST-1 skeleton did not affect H2 uptake. Both Li-doping and defect creation significantly enhanced H2 uptake to 3.03 wt%, which was caused by the coordination of Li ions with free carboxylic groups of the created defects via IP replacement.

Synthesis, structure and property investigation of a three-dimensional Zn(II) metal–organic frameworks

A new three-dimensional Zn(II) complex named [Zn(1,3-BMIB)(TBIP)⋅2H2O][Formula: see text] (1) (containning 1,3-BMIB = 1,3-bis(2-methyl-1H-imidazol-1-yl)benzene, H2TBIP=5-tert-butyl isophthalic acid) had been prepared by hydrothermal synthesis. Systematic structural characterization, especially the single crystal X-ray diffraction method, discreetly reveal the complex 1 exhibits three-dimensional (3D) framework with CdSO4 topology. The 3D crystrals 1 display solid-state fluorescence behavior at room temperature, indicating the potential of the candidate materials for absorbing and using visible light. The photocatalytic properties of compound 1 were estimated through the model photodecomposition dye pollutants using methylene blue (MB) and rhodamine B (RhB) under visible light irradiation.

Enhanced photocatalytic degradation performance of new and stable 2D/3D Ln-MOFs for tetracycline under visible light

Rational design of lanthanide metal-organic frameworks (Ln-MOFs) with high stability is of great significance for multifunctional applications. Ln-MOFs have attracted extensive attention in the field of photocatalysis due to their large specific surface area and strong visible light efficiency. In this paper, two 2D/3D Ln-MOFs with different spatial configurations have been successfully synthesized under solvothermal conditions, namely [La(HL)(H2O)]n·3H2O (1), [Er(HL)·3/2(H2O)]n·3/2H2O (2), where H4L = 5-(bis(3-carboxybenzyl)amino)isophthalic acid. Their structures were determined by X-ray single crystal diffraction analysis, and further characterized by XRD analysis and IR spectroscopy. The complex 1 shows layered structure, which extends into a three-dimensional (3D) supramolecular network by π-π interactions, the complex 2 exhibit 3D network structures with a Schläfli symbol of 412·63 topologies, respectively. BET test results showed that there were carboxylic acid groups without coordination in the structure of complex 1, with abundant active sites and higher adsorption activity than complex 2, which would promote the effective contact and reaction between the photocatalyst and tetracycline (TC), thus improving the photocatalytic efficiency of complex 1. Under visible light irradiation, complex 1 showed good photocatalytic degradation of TC, and the degradation rate of TC could reach 75.54% under 120 min. This can be attributed to the effective separation of photogenerated electron-hole pairs and adsorption properties of complex 1. This study provides a new idea for MOFs as an efficient photocatalyst to degrade antibiotic pollutants.

Synthesis of isophthalic acid-carbazole coordination polymers with stacking-dependent ultralong room temperature phosphorescence and white-light emission

Exploiting the relationship between the stacking modes of molecules and room-temperature phosphorescence (RTP) performance is of great important to design afterglow materials. A series of coordination polymers [Cd(CzIP)] (1) (H2CzIP = 5-(carbazol-9-yl) isophthalate), [Cd(CzIP)(DMI)] (2) (DMI = 1,3-Dimethyl-2-imidazolidinone) and [Cd2(CzIP)2(H2O)2] (3) base on carbazole–isophthalic acid are synthesized via a solvothermal method. These compounds exhibit stacking-dependent RTP. Compounds 1 and 2 exhibit obvious time-dependent RTP with the afterglow color from orange to green, and show white-light emission owing to fluorescence and phosphorescence dual emission. Compound 3, which features the strong π‒π stacking, showed the weakest phosphorescence with the shortest lifetime. It reveals that the phosphorescence efficiency is not proportional to the overlap of π-π stacking, the triplet excited states of discrete dimer mode rather than H-aggregation can dominate the generation of room-temperature phosphorescence. These results indicate that coordination induction is an efficient approach to regulate the aggregation of chromophores, further modulating the room-temperature phosphorescence.

Detection of nitroaromatics by a Zn(II)-containing coordination polymer derived from a 1,2,3-triazole-based tricarboxylate ligand

The Dimroth azide–enolate cycloaddition between dimethyl 5-azidoisophthalate and ethyl acetoacetate was used to generate 5-(4-carboxy-5-methyl-1H-1,2,3-triazol-1-yl)isophthalic acid (H3L) as a novel tricarboxylate ligand with a 1,2,3-triazole ring in the central unit with a view to employ it in the preparation of coordination polymers. The reaction of this ligand with Zn(NO3)2·6H2O in a mixture of N,N-dimethylformamide (DMF) and water at 95 °C for 72 h afforded [Zn4L2(OH)2(H2O)DMF2]n, which has been characterized by single crystal X-ray crystallography, infrared spectroscopy, thermogravimetry, powder X-ray diffraction and elemental analysis. The fluorescence of this coordination polymer was investigated, and its ability to detect various nitroaromatics by fluorescence quenching was examined. 4-Nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol and 4-nitrotoluene have been identified as the aromatic nitroderivatives for which the coordination polymer exhibits a fluorescence quenching in the range of 91% to 82%.

Rapid Identification of Enamine‐based Organocatalysts for Quaternary Carbon‐containing Aldol Reactions via Fluorescence‐based Screening

AbstractFluorescent sensors can directly monitor the progression of chemical transformations through increases in fluorescence intensity to allow rapid identification of superior organocatalytic systems. Based on data from more than 4,000 screenings, a combination of pyrrolidine and isophthalic acid was identified as a catalyst template for the quaternary carbon‐containing aldol reaction. Following fine‐tuning of the catalyst template, 5‐hydroxy isophthalic acid was confirmed as an additive with high reactivity.