DMF Molecules Research Articles

Five Lanthanide-Based Metal–Organic Frameworks Built from a π-Conjugated Ligand with Isophthalate Units Featuring Sensitive Fluorescent Sensing for DMF and Acetone Molecules

Five novel lanthanide metal–organic frameworks constructed from a π-conjugated ligand with tetracarboxylate group, 5,5′-(naphthalene-1,5-diyl)diisophthalic acid, have been synthesized solvothermall...

A series of new hetero-decanucleus sandwich Cd–Ln clusters constructed from open-chain ether Schiff base and niacin ligands: Synthesis, structure, luminescence and antioxidant activity

Three heteronuclear Cd–Ln clusters based on open-chain ether Schiff (bis(5-bromine-3-methoxysalicylidene)-3-oxapentane-1,5-diamine (H2L) and niacin (NA), with composition [Cd6Ln4L5 (OAc)5(NA)5(CH3OH)5](NO3)4·x(CH3OH)·y(CH2Cl2) (1 Ln = Sm, x = 1, y = 1; 2 Ln = Eu, x = 0, y = 1; 3 Ln = Tb, x = 2, y = 1), have been synthesized and structural characterizated. The structure analysis reveals that 1–3 contain the similar sandwich-type polycationic unit [Cd6Ln4L5(OAc)5(NA)5(CH3OH)5]4+. Solid-state luminescence studies show that the emission peaks of the H2L ligand located in the range of 340 ~ 373 nm in 1–3. The characteristic emission peaks of Sm3+ ion appear in cluster 1, but there is no Eu3+ or Tb3+ ion emission peak in clusters 2 and 3. The fluorescence spectra of 1–3 in N,N-dimethylformamide (DMF) solution only appear emission peaks of π*→π transition of [CdL] coordination units, but characteristic emission peaks of Ln3+ ions didn’t emerge. It is possible that the DMF molecules impeded the energy transfer from [CdL] coordination units to the lanthanum(III) ions. Moreover, antioxidation properties indicate that H2L and 1–3 have outstanding biological activity in scavenging oxygen free radicals.

Cu(II) coordination polymers with 4,4′-bipyridine. Synthesis and crystal structures

Extensively research has been devoted to the isolation and characterization of Cu(II) coordination polymers. Since many aspects can influence the final crystal structure, the effect of the solvent molecules through intermolecular interactions has been proven to be a determining factor. Herein, we elucidated the structure of two Cu(II) concomitant 1D polymers containing piperonylic acid (HPip) and 4,4′-bipyridine (4,4′-bipy), which were simultaneously crystallized and subsequently isolated changing the synthetic conditions. Complex {[Cu(Pip)2(4,4′-bipy)]}n (1) exhibits zig-zag polymeric chains while {[Cu(Pip)2(4,4′-bipy)(H2O)]•1/2(4,4′-bipy)•(DMF)}n (2) displays linear polymeric chains stacked by water•••carboxylate intermolecular interactions, forming voids occupied by alternated guest 4,4′-bipy and DMF molecules.

Paraoxonase Mimic by a Nanoreactor Aggregate Containing Benzimidazolium Calix and l-Histidine: Demonstration of the Acetylcholine Esterase Activity.

An anion-mediated preorganization approach was used to design and synthesize the benzimidazolium-based calix compound R1⋅2 ClO4 - . X-ray crystallography analysis revealed that the hydrogen-bonding interactions between the benzimidazolium cations and N,N-dimethylformamide (DMF) helped R1⋅2 ClO4 - encapsulate DMF molecule(s). A nanoreactor, with R1⋅2 ClO4 - and l-histidine (l-His) as the components, was fabricated by using a neutralization method. The nanoreactor could detoxify paraoxon in 30 min. l-His played a vital role in this process. Paraoxonase is a well-known enzyme used for pesticide degradation. The Ellman's reagent was used to determine the percentage inhibition of the acetylcholinesterase (AChE) activity in the presence of the nanoreactor. The results indicated that the nanoreactor inhibited AChE inhibition.

Formation and thermal stability of supramolecular complexes of dibromosubstituted zinc(II) dipyrromethenate with ethanol and N,N – dimethylformamide

Crystal solvates of zinc(II) 3,3′,5,5′-tetramethyl-4,4′-dibromo-dipyrromethenate [ZnL2] form supramolecular complexes [ZnL2(C2H5OH)2] and [ZnL2(DMF)2] with molecules of ethanol and DMF. Such complexes are stable up to ∼ 150 and 111 °C, respectively. According to the quantum chemical calculations, [ZnL2(DMF)2] is formed due to the additional coordination of molecular ligands by the zinc atom (Znδ+ ⟵: O). In the case of [ZnL2(C2H5OH)2], along with weak coordination interactions of the hydroxyl group oxygen with the zinc ion, the main contribution to the suprastructure formation is made by hydrogen bonds (C2H5OH ⟵ :N≤), which makes both the destruction onset temperature and the total enthalpy (ΔHΣ) of the intermolecular interactions in [ZnL2(C2H5OH)2] much higher than in [ZnL2(DMF)2]. The obtained results are interesting for the development of new [ZnL2] fluorescent sensors of N- and O-containing analytes.

Dipyridine Amine Octamolybdates Hybrid Material Effectively Catalyzed Oxidation of Sulfide Derivatives with Hydrogen Peroxide

With the increasing interest in polyoxometalates (POMs) materials over the past few decades, scientific researchers have focused their attention on the fruitful utilization of POMs hybrids as efficient catalysts in many organic reactions. In this paper, dipyridine amine (dpa) organic ligand hybrid polyoxomolybdate material was solvothermally synthesized and structurally identified by elemental analysis, X-ray diffraction and infrared spectrum. Structural refinement of the hybrid polyoxomolybdate compound 1 with general formula [Hdpa]4Mo8O26 · 2DMF (DMF = N,N-dimethylformamide) shows that compound 1 presents in the space group P-1 with triclinic system, and is built up from a well-known β-[Mo8O26]4– anionic cluster, four free protonated dpa cations and two free DMF molecules. Remarkably, the β-Mo8O26-based hybrid material was further applied as the catalyst in the conversion of sulfides utilizing hydrogen peroxide (30%) as green terminal oxidant and exhibited efficient catalytic activities for selective oxidation of sulfides.

Adsorption of bromide and iodide anions on a renewable liquid (Cd–Ga) electrode from acetonitrile solutions. Effect of (Cd–Ga)–solvent chemisorption interaction on the anion adsorption energy

The specific adsorption of bromide and iodide anions was studied at a (Cd–Ga)/acetonitrile (AN) interface from mixed solutions of [0.1 m M LiBr + 0.1 (1–m) M LiBF4] and [0.1 m M LiI + 0.1 (1–m) M LiBF4] at the following values of molar fraction m of the surface–active anion: 0, 0.01, 0.02, 0.05, 0.1, 0.2, 0.5, and 1. The main experimental method was measurement of differential capacitance on a renewable liquid (Cd–Ga) electrode. The obtained experimental results can be described quantitatively by the Frumkin isotherm in a wide range of charge densities (σ). The adsorption parameters of halide anions (Hal−) were determined using regression analysis of two-dimensional pressure isotherms. It is shown that the adsorption energies (ΔGads) of Br− and I− at the (Cd–Ga)/AN interface practically coincide. It follows that the difference in the interaction energies of Br− and I− with (Cd–Ga) is equal to the difference of the solvation energies of these anions: (ΔG(Cd‐Ga)‐Br‐ − ΔG(Cd‐Ga)‐I‐)≈(ΔGAN‐Br‐ − ΔGAN‐I‐) and therefore ΔG(Cd-Ga)-I− < ΔG(Cd-Ga)-Br−. The adsorption parameters of Hal− obtained on the (Cd–Ga)/AN interface are compared with the similar data for the (Cd–Ga)/DMF interface. The adsorption energy of Br− and I− on a (Cd–Ga) electrode increases significantly in AN as compared to DMF. This result can be unambiguously explained by a significant decrease in the energy of chemisorption interaction between a (Cd–Ga) electrode and solvent molecules in the Helmholtz layer upon transition from DMF to AN. The ΔGads,σ-dependence obtained at the (Cd–Ga)/AN interface in the first approximation characterizes the change of the free energy of (Cd–Ga)–Hal− interaction with σ. It is shown that the slope of the ΔGads, σ-dependence decreases upon transition from the (Cd–Ga)/AN interface to the (Cd–Ga)/DMF interface due to a significant increase in the energy of the chemisorption interaction of (Cd–Ga) with DMF molecules in the Helmholtz layer during the transition from negative to positive values of charge density.

Topological Strain-Induced Regioselective Linker Elimination in a Chiral Zr(IV)-Based Metal-Organic Framework

Summary Zr-carboxylate metal-organic frameworks (MOFs) are structurally robust materials, in part due to their strong coordination bonds. The regioselective Zr–O bond cleavage and formation between 3D architectures are thus challenging and are heretofore unexplored. In this work, by introducing highly flexible 18-crown-6-ether functionalities into a homochiral Zr-MOF, we report an unprecedented topology transition in which a 4,10-connected framework undergoes a rapid solid-state transition into a thermodynamically more stable 4,8-connected analog by a regioselective-linker-elimination under ambient conditions. The transition process was unambiguously unraveled by single-crystal and powder X-ray diffraction studies, and we proposed a possible transition mechanism based on various control experiments and theoretical calculations. The excellent chemical stability and substantially expanded porosity and pore apertures endowed the transformed chiral MOF with an exceptional capacity for the enantioadsorptive and solid-phase extractive separation of the racemic drug molecule of lansoprazole with 98% ee and 93% ee, respectively.

Three stages of hydrogen bonding network in DMF-water binary solution

Three stages of hydrogen bonding (HB) network in N, N-dimethylformamide (DMF)-water binary solution were investigated by Raman spectroscopy with different mixing ratios at room temperature and atmospheric pressure. The results show that the addition of DMF strengthens the HB network of water when the volume fraction of DMF (VDMF) is less than 0.4. However, the tetrahedral structure of water is destroyed when VDMF reaches 0.4, and water molecules and DMF molecules form two DMF-water complexes, namely DMF·3H2O and DMF·2H2O. While VDMF reaches 0.8, the DMF-water complex is transformed into DMF·H2O structure due to the instability of DMF·nH2O (n = 2, 3). In addition, the newly formed HB C=O···H-C, rather than the weak HB C-H···O, leads to the red shift of C–H stretching vibration mode.

Synthesis and Structural Study of 2D Coordination Polymers of Zn(II), Cd(II) and Mn(II) Based on Diaminobenzoylglyoxime

The condensation of m-aminobenzoic acid with dichloroglyoxime has resulted in a new dioxime, di-m-aminobenzoyl glyoxime (DmabaH4) (I). Based on the latter, coordination 2D polymers {[Zn(DmabaH2)(H2O)(dmf)] ⋅ dmf}n (II), {[Cd(DmabaH2)(H2O)2] ⋅ 0.5dmf ⋅ 4H2O}n (III), and {[Mn(DmabaH2)(H2O)(dmf)] ⋅ dmf}n (IV) have been sythesized. The compositions and structures of new Zn(II), Cd(II), and Mn(II) compounds have been determined by various physicochemical methods, including X-ray diffraction (CIF files CCDC nos. 2 004 634 (II), 2 004 635 (III), and 2 004 636 (IV)). In compounds II–IV, DmabaH4 acts as a bridging ligand, which is tetradentate coordinated as a dianion by three metal ions using a donor set of N2O2 atoms. This ligand is coordinated by one metal atom through two nitrogen atoms of the dioxime fragment in a bidentate chelate manner forming five-membered chelate rings, and by the other two monodentally using two oxygen atoms belonging to the carboxyl groups of two benzoic fragments. The coordination polyhedra of metal atoms in II–IV are completed to octahedrons by oxygen atoms of dmf and water molecules; the donor set of atoms is N2O4.

Strontium-Based MOFs Showing Dual Emission: Luminescence Thermometers and Toluene Sensors.

This work reports on the preparation and optical characterization of two metal-organic frameworks (MOFs) based on strontium ions and 2-amino-1,4-benzenedicarboxylate (NH2-bdc) ligand: i.e., [Sr(NH2-bdc)(DMF)]n (1) and {[Sr(NH2-bdc)(Form)]·H2O}n (2) (where DMF = dimethylformamide and Form = formamide). Compound 1 has a 3D architecture built up from the linkage established by NH2-bdc among metal-carboxylate rods, leaving significant microchannels that are largely occupied by DMF molecules coordinated to strontium centers. The solvent molecules play a crucial role in the photoluminescence (PL) properties, which has been deeply characterized by diffuse reflectance and variable-temperature emission. Interestingly, both materials present intriguing photoluminescence (PL) properties involving intense short-lived and long-lasting phosphorescence (LLP), though the latter is especially remarkable for compound 2 with a lifetime of 815 ms at low temperature. Conversely, the strong PL shown by 1 may be successfully exploited due to both its luminescent thermochromism observed in the RT to 10 K range and its solvent-dependent PL sensing capacity, imbuing this material with potential activity as a PL thermometer as well as a toluene detector in water solutions.

A Detailed Kinetico-Mechanistic Investigation on the Palladium C-H Bond Activation in Azobenzenes and Their Monopalladated Derivatives.

Palladium C-H bond activation in azobenzenes with R1 and R2 at para positions of the phenyl rings (R1 = NMe2, R2 = H (L1); R1 = NMe2, R2 = Cl (L2); R1 = NMe2, R2 = I (L3); R1 = NMe2, R2 = NO2 (L4); R1 = H, R2 = H (L5)) and their monopalladated derivatives, using cis-[PdCl2(DMF)2], has been studied in detail by in situ 1H NMR spectroscopy in N,N-dimethylformamide-d7 (DMF-d7) at room temperature; the same processes have been monitored in parallel via time-resolved UV-vis spectroscopy in DMF at different temperatures and pressures. The final goal was to achieve, from a kinetico-mechanistic perspective, a complete insight into previously reported reactivity results. The results suggest the operation of an electrophilic concerted metalation-deprotonation mechanism for both the mono- and dipalladation reactions, occurring from the coordination compound and the monopalladated intermediates, respectively. The process involves deprotonation of the C-H bond assisted by the presence of a coordinated DMF molecule, which acts as a base. For the first time, NMR monitoring provides a direct evidence of all the intermediate stages: that is, (i) coordination of the azo ligand to the PdII center, (ii) formation of the monopalladated species, and (iii) coordination of the monopalladated species to another PdII unit, which finally result in the (iv) formation of the dipalladated product. All of these species have been identified as intermediates in the dipalladation of azobenzenes, evidenced also by UV-vis spectroscopy time-resolved monitoring. The data also confirm that the cyclopalladation of asymmetrically substituted azobenzenes occurs by two concurrent reaction paths. In order to identify the species observed by NMR and by UV-vis spectroscopy, the final products, intermediates, and the PdII precursor have been prepared and characterized by X-ray diffraction and IR and NMR spectroscopy. DFT calculations have also been used in order to explain the isomerism observed for the isolated complexes, as well to assign their NMR and IR spectra.

Solvation Structure of Li+ in Concentrated Acetonitrile and N,N-Dimethylformamide Solutions Studied by Neutron Diffraction with 6Li/7Li Isotopic Substitution Methods.

Neutron diffraction measurements on 6Li/7Li isotopically substituted 10 and 33 mol % *LiTFSA (lithium bis(trifluoromethylsulfonyl)amide)-AN-d3 (acetonitrile-d3) and 10 and 33 mol % *LiTFSA-DMF-d7(N,N-dimethylformamide-d7) solutions have been carried out in order to obtain structural insights on the first solvation shell of Li+ in highly concentrated organic solutions. Structural parameters concerning the local structure around Li+ have been determined from the least squares fitting analysis of the first-order difference function derived from the difference between carefully normalized scattering cross sections observed for 6Li-enriched and natural abundance solutions. In 10 mol % LiTFSA-AN-d3 solution, 3.25 ± 0.04 AN molecules are coordinated to Li+ with a intermolecular Li+···N(AN) distance of 2.051 ± 0.007 Å. It has been revealed that 1.67 ± 0.07 AN molecules and 2.00 ± 0.01 TFSA- are involved in the first solvation shell of Li+ in the 33 mol % LiTFSA-AN solution. The nearest neighbor Li+···NAN and Li+···OTFSA- distances are obtained to be r(Li+···N) = 2.09 ± 0.01 Å and r(Li+···O) = 1.88 ± 0.01 Å, respectively. The first solvation shell of Li+ in the 10 mol % LiTFSA-DMF-d7 solutions contains 3.4 ± 0.1 DMF molecules with an intermolecular Li+···ODMF distance of 1.95 ± 0.02 Å. In highly concentrated 33 mol % LiTFSA-DMF-d7 solutions, there are 1.3 ± 0.2 DMF molecules and 3.2 ± 0.2 TFSA- in the first solvation shell of Li+ with intermolecular distances of r(Li+···ODMF) = 1.90 ± 0.02 Å and r(Li+···OTFSA-) = 2.01 ± 0.01 Å, respectively. The Li+···TFSA- contact ion pair stably exists in highly concentrated 33 mol % LiTFSA-AN and -DMF solutions.

Catalytic CO2 fixation over a high-throughput synthesized copper terephthalate metal-organic framework

In this study, a porous copper metal-organic framework with terephthalate linker, Cu(TPA), was synthesized in DMF via a high-throughput (gram quantities) solvothermal method. Cu(TPA) that arranged in the C2/m space group upon an innovative controlled thermal treatment through removing coordinated DMF molecules to the Cu(II) center provided large square pores with Lewis acidic Cu(II) sites. Upon a novel activation strategy, DMF molecules in the structure of Cu(TPA) were partially eliminated to act as polar groups to enhance the affinity of CO2 into the catalysts. The synergistic effect of Cu(II) metal center with DMF decorated pores was deliberate in the cycloaddition reaction of epoxides with CO2. The partially activated Cu(TPA), Cu(TPA)′, in treating with CO2 that coordinate to the Cu(II) centers in the two-dimensional tunnels revealed excellent heterogeneous catalytic entitativity in solvent-free conditions toward CO2 fixation to cyclic carbonates. Besides, for several cycles, the Cu(TPA) catalyst under mild conditions was simply recycled and reused with a little loss in catalytic performance.

3,5-dibromo-4-hydroxybenzaldehyde dissolved in aqueous solutions of ethanol, n-propanol, acetonitrile and N,N-dimethylformamide: Solubility modelling, solvent effect and preferential solvation investigation

Equilibrium solubility of 3,5-dibromo-4-hydroxybenzaldehyde in four aqueous solutions of ethanol/n-propanol/acetonitrile/N,N-dimethylformamide (DMF) was determined at temperatures covering from 278.15 K to 323.15 K. All determinations were carried out by the well-known saturation shake-flask method under atmospheric pressure of 101.2 kPa. The maximum values of solubility data appeared in neat ethanol/n-propanol/acetonitrile/DMF for each solution. By Jouyban-Acree model, Apelblat-Jouyban-Acree model and van’t Hoff-Jouyban-Acree model, the 3,5-dibromo-4-hydroxybenzaldehyde solubility was well mathematically described obtaining RAD values smaller than 3.71% and RMSD values smaller than 2.27 × 10-4. The Kamlet and Taft linear solvation energy relationships were employed to examine the chief factors describing solvent effect. The cavity formation energy of solvents played a significant role on the solubility variation of 3,5-dibromo-4-hydroxybenzaldehyde in different aqueous solutions. The local mole fractions of ethanol/n-propanol/acetonitrile/DMF and water molecules around the 3,5-dibromo-4-hydroxybenzaldehyde molecule were quantitatively studied via the Inverse Kirkwood–Buff integrals way used to the solubility values. 3,5-Bibromo-4-hydroxybenzaldehyde was preferentially solvated by water in water-rich compositions for the ethanol/n-propanol/acetonitrile/DMF + water mixtures; while within co-solvent-rich and intermediate compositions, 3,5-dibromo-4-hydroxybenzaldehyde was preferentially solvated by ethanol/n-propanol/acetonitrile/DMF.

Intermolecular interactions and disorder in six isostructural celecoxib solvates.

Six isostructural crystalline solvates of the active pharmaceutical ingredient celecoxib {4-[5-(4-methylphenyl)-3-(trifluoromethyl)pyrazol-1-yl]benzenesulfonamide; C17H14F3N3O2S} are described, containing dimethylformamide (DMF, C3H7NO, 1), dimethylacetamide (DMA, C4H9NO, 2), N-methylpyrrolidin-2-one (NMP, C5H9NO, 3), tetramethylurea (TMU, C5H12N2O, 4), 1,3-dimethyl-3,4,5,6-tetrahydropyrimidin-2(1H)-one (DMPU, C6H12N2O, 5) or dimethyl sulfoxide (DMSO, C2H6OS, 6). The host celecoxib structure contains one-dimensional channel voids accommodating the solvent molecules, which accept hydrogen bonds from the NH2 groups of two celecoxib molecules. The solvent binding sites have local twofold rotation symmetry, which is consistent with the point symmetry of the solvent molecule in 4 and 5, but introduces orientational disorder for the solvent molecules in 1, 2, 3 and 6. Despite the isostructurality of 1-6, the unit-cell volume and solvent-accessible void space show significant variation. In particular, 4 and 5 show an enlarged and skewed unit cell, which can be attributed to a specific interaction between an N-CH3 group in the solvent molecule and the toluene group of celecoxib. Intermolecular interaction energies calculated using the PIXEL method show that the total interaction energy between the celecoxib and solvent molecules is broadly correlated with the molecular volume of the solvent, except in 6, where the increased polarity of the S=O bond leads to greater overall stabilization compared to the similarly-sized DMF molecule in 1. In the structures showing disorder, the most stable orientations of the solvent molecules make C-H...O contacts to the S=O groups of celecoxib.

The Influence of N,N-Dimethylformamide on Dispersion of Multi-Walled Carbon Nanotubes

Preparation of highly homogeneous disperse ions multi-walled carbon nanotubes (MWCNTs) has vital effect on their applications. In this research, the ultrasonication and heat treatment were used to prepare suspensions of MWCNTs using N,N-dimethylformamide (DMF) as dispersant innovatively. The suspensions were characterized by UV–Vis absorbance spectroscopy, adsorption isotherm, transmission electron microscopy, atomic force microscope and fourier transform infrared. The experimental results showed that the optimum concentration of DMF was 0.9 g/L, the best sonication time was 30 min and the optimum temperature was 50°C; The TEM and AFM images showed that the agglomeration of bundles was broken up, and the thickness of MWCNTs decreased because of the incorporation of DMF. In addition, the dispersing mechanism is that molecules of DMF get into the space of MWCNTs bundles to break up the aggregation, and amide groups of DMF easily form intermolecular hydrogen bonds to decrease surface tension. Using DMF to disperse MWCNTs had a remarkable effect, dispersed MWCNTs may be added into cement-based materials or other composite materials to improve their performance.

Structures, magnetic properties, and EPR studies of tetranuclear copper(II) complexes [Cu4(OH)4L4]4+ (L = bpa, bipy) stabilized by anions containing decahydro-closo-decaborate anion

Tetranuclear copper(II) cationic complex [Cu4(bpa)4(OH)4]4+ stabilized by chained polymeric silver(I) anionic complex {Ag[B10H10]}nn− and two DMF molecules with the general formula {[Cu4(bpa)4(OH)4(DMF)2][Ag[B10H10]]4·10 DMF}n has been synthesized. The target complex has been prepared in one step when [Ag2[B10H10]] was allowed to react with CuCl in the presence of bpa in DMF; the reaction has been performed in air. Copper(I) has been oxidized in air in the presence of bpa to form the tetranuclear cationic complex. The target compound has been studied by IR spectroscopy as well as powder and single crystal X-ray diffractions. The electronic structure and magnetic properties of the complex have been studied by EPR spectroscopy and magnetic susceptibility methods and the obtained data have been compared with those obtained for related tetranuclear bipy-contained copper(II) complexes [Cu4(bipy)4(OH)4][Cu2[B10H10]3]·4CH3CN and {[Cu4(bipy)4(OH)4][B10H10]2(DMSO)2} with the known structures. The magnetic properties of three compounds under study are different; the magnetic moment has been found to increase, to decrease and remain unchanged when increasing temperature.

The structure of water-DMF binary mixtures probed by linear and nonlinear vibrational spectroscopy.

Attenuated total reflectance Fourier transform infrared spectroscopy and sum frequency generation (SFG) vibrational spectroscopy have been employed to probe the molecular structure of N,N-dimethylformamide (DMF) and water mixture by varying the concentration of DMF. From the bulk studies, we observed a gradual decrease in the intensity with a continuous blue shift in the OH-stretch region with the increase in the DMF concentration. In contrast, no significant blue shift in the OH-stretch region is noticed from the SFG spectra collected from the air-aqueous binary mixture interface as a function of DMF concentration. However, the impact of DMF is found to be disruptive in nature toward the existing hydrogen bonding network of the pristine water at the interfacial region. Interestingly, in the CH-stretch region, the vibrational signatures of the DMF molecule show blue shifts, as proposed in earlier studies. We have calculated the molecular tilt angle of the methyl group of the DMF molecule as a function of DMF concentration. For the case of neat DMF, the observed tilt angle is ∼17.7° with respect to the surface normal. The value of tilt angle decreases with the decrease in DMF concentration and reaches a value of ∼1.7° for a mole fraction of 0.5, and it further increases with the decrease in DMF concentration. It achieves a value of ∼20° for the dilute DMF mole fraction of 0.05 in the binary mixture. This indicates that DMF molecules at the air-binary mixture interface are placing their methyl groups more toward the normal for the intermediate DMF concentrations.

Synthesis of an Interrupted AST‐Type Zeolitic Imidazolate Framework

Summary of main observation and conclusionPresented here is a new interrupted AST‐type zeolitic imidazolate framework, Zn5(OH)(dmbim)9(H2O)• 4(DMF) (1) with cub and interrupted ast cages, which exhibits permanent porosity, high hydrophobicity and strong solid‐state photoluminescent properties. More importantly, structural ordered DMF molecules are firmly confined in the ‐ast cage by strong host‐guest interactions.