High Polar Solvents Research Articles

Ultrathin membranes comprising polymers of intrinsic microporosity oligomers for high-performance organic solvent nanofiltration

Microporous organic polymers (MOPs) featuring chemically rigid backbones and permanent micropores are desirable for fabricating molecular selective membranes towards organics separation. However, coordinating facile film processing with high micropore persistence remains a challenge. In this paper, a low molecular weight polymers of intrinsic microporosity was rationally designed by precisely controlling the stoichiometric equilibrium of polymerization monomer. The polymers of intrinsic microporosity oligomers combine rigid and contorted structures with the aqueous solution processability, promoting the formation of 25-nm-thick polyacrylamide nanofilms with enhanced microporosity via support-free interfacial polymerization (SFIP). The resulting composite membranes have superior retention of small molecular solutes and high nonpolar and polar solvent permeances. Experiment and simulation results show that their excellent separation performance is due to substantially open and interconnected microporosity formed in the polymer networks based on rigid and contorted diamines as well as reduced film thickness. This study provides a new sight for using MOPs to construct high-microporosity membranes for precise and rapid molecular sieving.

Novel Cu(II) and Zn(II) Nanocomplexes Based on 5,6‐Diphenyl‐1,2,4‐Triazine: Preparation, Spectroscopic, TD‐DFT Calculations, Molecular Docking and Solvatochromic Studies

ABSTRACTThe reaction between 2‐hydroxy‐1‐naphthaldehyde and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine produced a novel hydrazone ligand (DTHMN), which reacted with Cu(II) and Zn(II) metal ion in molar ratio 1:1, giving octahedral Cu(II)‐DTHMN and tetrahedral Zn(II)‐DTHMN nanosized complexes. The structural geometries have been elucidated on the basis of elemental analysis, nuclear magnetic resonance, infrared, electronic, and electron spin resonance spectra, and magnetic and molar conductance measurements as well as x‐ray diffraction and thermal analysis. TEM analysis showed that Zn(II)‐DTHMN complex has nano‐rode morphology shape. On the other hand, Cu(II)‐DTHMN has sphere shape within nanodomain. The DTHMN ligand exhibits ONN chelating sites through N‐triazine ring, azomethine nitrogen, and deprotonated OH group, forming the mononuclear metal complexes. The synthesized compounds showed a distinct solvatochromic behavior in different polar solvents. A bathochromic alteration is observed when moving from less to high polar solvents, indicating strong solute–solvent interactions accompanied by intramolecular charge transfer (ICT). The ground and excited state dipole moments of these compounds were determined experimentally by solvatochromic shift method using Bilot–Kawski, Lippert–Mataga, Bakhshiev, and Kawski–Chamma–Viallet functions and a microscopic Reichardt's solvent polarity parameter (ETN). The dipole moment is increased significantly upon excitation referring to stabilizing the excited species includes n–π* transition by polarity of solvent. The experimental results are generally consistent with those values obtained by B3LYP/GENECP method at 6‐311G(d,p) basis set for C, H, N, and O atoms and SDD (Stuttgart/Dresden) basis set for the metal atoms. The compounds were tested for antimicrobial efficiency against Gram‐positive bacteria, Gram‐negative bacteria, and fungus strain. Finally, molecular docking was used to study the interactions between donors (the current compounds) and receptors FabH–CoA complex (PDB code: 1HNJ).

Designing Stimuli-Responsive Supramolecular Gels by Tuning the Non-Covalent Interactions of the Functional Groups.

The physical characteristics of a supramolecular gel are greatly influenced by the nature and arrangement of functional groups in the gelator. This work focuses on the impact of the functional groups, specifically the hydroxyl group, on the stimuli-responsive properties of a gel. We used a C3-symmetric benzene-1,3,5-tricarboxamide (BTA) platform, which was attached to the methyl ester of phenylalanine (MPBTA) and tyrosine (MTBTA). The gelation studies revealed that MPBTA gelled in alcohols, non-polar aromatic solvents, and aqueous mixtures (1:1, v/v) of high-polar solvents, whereas MTBTA gelled only in an aqueous mixture of DMF (1:1, v/v). The mechanical and thermal strength of the gels were evaluated by rheological and Tgel studies, and the results indicated that MPBTA gels were stronger than MTBTA gels. The gels were characterized by powder X-ray diffraction and scanning electron microscopy (SEM). The analysis of stimuli-responsive properties revealed that MPBTA gels were intact in the presence of sodium/potassium salts, but the MTBTA gel network was disrupted. These results indicate that the elegant choice of functional groups could be used to tune the constructive or destructive stimuli-responsive behavior of gels. This study highlights the significant role of functional groups in modulating the stimuli-responsive properties of supramolecular gels.

One-pot synthesis of 5-norbornene-2,3-dicarboxylic anhydride with high exo/endo ratio in a microreactor under high temperature and appropriate pressure

5-Norbornene-exo-2,3-dicarboxylic anhydride (exo-NDA), widely used in the synthesis of medicine and pesticide, was primarily obtained through the subsequent thermal isomerization of 5-norbornene-endo-2,3-dicarboxylic anhydride (endo-NDA) synthesized from cyclopentadiene (CPD) and maleic anhydride (MAH). Herein, density functional theory (DFT) was employed to elucidate the transition states and reaction pathways of different configurations. The endo-path exhibited a lower energy barrier, and the exo-isomer demonstrates greater structural stability. It was found that both high temperature and solvent polarity influenced the generation of NDA with different configurations. Due to considering solubility of MAH, an acetone/ethylbenzene mixed solvent was chosen for the reaction instead. According to the DFT calculations, we developed continuous-flow microreactor for high-efficiency one-pot synthesis of the isomers with exo/endo ratio of up to 1.19:1 as well as almost 100 % conversion and 98 % selectivity just in 2 min at 260 °C and 4 MPa, which CPD was generated in situ to participate in a series of Diels-Alder reactions instead of dicyclopentadiene as raw material existed at room temperature. Moreover, excessive or insufficient pressure in the reaction system should elevate byproduct formation, resulting in a decrease in reaction selectivity, as could prolonged residence time.

Orthogonal Electrochemical Stability of Bulk and Surface in Lead Halide Perovskite Thin Films and Nanocrystals.

Lead halide perovskites have attracted significant attention for their wide-ranging applications in optoelectronic devices. A ubiquitous element in these applications is that charging of the perovskite is involved, which can trigger electrochemical degradation reactions. Understanding the underlying factors governing these degradation processes is crucial for improving the stability of perovskite-based devices. For bulk semiconductors, the electrochemical decomposition potentials depend on the stabilization of atoms in the lattice-a parameter linked to the material's solubility. For perovskite nanocrystals (NCs), electrochemical surface reactions are strongly influenced by the binding equilibrium of passivating ligands. Here, we report a spectro-electrochemical study on CsPbBr3 NCs and bulk thin films in contact with various electrolytes, aimed at understanding the factors that control cathodic degradation. These measurements reveal that the cathodic decomposition of NCs is primarily determined by the solubility of surface ligands, with diminished cathodic degradation for NCs in high-polarity electrolyte solvents where ligand solubilities are lower. However, the solubility of the surface ligands and bulk lattice of NCs are orthogonal, such that no electrolyte could be identified where both the surface and bulk are stabilized against cathodic decomposition. This poses inherent challenges for electrochemical applications: (i) The electrochemical stability window of CsPbBr3 NCs is constrained by the reduction potential of dissolved Pb2+ complexes, and (ii) cathodic decomposition occurs well before the conduction band can be populated with electrons. Our findings provide insights to enhance the electrochemical stability of perovskite thin films and NCs, emphasizing the importance of a combined selection of surface passivation and electrolyte.

First-principles study of solvent polarity effects in the Menshutkin reaction

Quaternary ammonium salts (QASs) have been used as antimicrobial agents, surfactants, and ionic liquids in electrical double-layer capacitors, rechargeable lithium-ion batteries, and dye-sensitized solar cells. It is well known that solvents and reactants strongly affect the Menshutkin reaction. However, QASs are potentially harmful to humans and the environment. To address these issues, we report the effects of solvent polarity on the thermochemistry of two selected Menshutkin reactions, (1) trimethylamine and 1-iodopropane yielded propyltrimethylammonium, and (2) methylacetamide and 1-iodopropane yielded acetylpropylmethylammonium. We systematically constructed possible QAS unique conformers within the first-principles framework in solvents that have three various polarities: toluene, acetonitrile, and water. The polar solvent shifted both reactions toward exergonic and decreased the Gibbs free activation energy. In addition, the polar solvent changed the favorable reaction for the acetylpropylmethylammonium formation only due to an intramolecular hydrogen bond. Therefore, we suggest that selecting high solvent polarity should be considered to address the potential health and environmental effect.

Effects of solvent extraction on the phytoconstituents and in vitro antioxidant activity properties of leaf extracts of the two selected medicinal plants from Malawi

This study evaluated and compared the phytochemical and antioxidant properties of the solvent extracts of Azadirachta indica A. Juss and Vernonia amygdalina Del leaves. Methanolic and aqueous extracts showed high (P ≤ 0.05) extract yields (in %), compared to chloroform and ethyl acetate extracts from both V. amygdalina and A. indica leaves. The study exhibited high phytochemical content in methanol and aqueous extracts compared to chloroform and ethyl acetate extracts, confirming the potential for medicinal use. V. amygdalina methanol and aqueous extracts had higher (P ≤ 0.05) total phenolic content (TPC), in mg GAE/gDW, (158.810±0.846 and 217.883±0.265, respectively) than chloroform (37.574±0.118) and ethyl acetate (104.758±0.236) but higher ethyl acetate content in A. indica extracts. Low polar solvents extracted high (P ≤ 0.05) total flavonoids, in mgQE/gDW, (367.051±0.858 and 149.808±0.009) compared to high polar solvents (14.863±0.071 and 54.226±0.014 ) in V. amygdalina while as in A. indica leaf extracts, low polar solvents showed high TFC ( 658.469±3.451 and 275.288±10.490) compared to high polar solvents (26.312±0.063 and 48.858±0.063) respectively. In vitro total antioxidant capacity, in mg/g, was higher in polar solvents than in low-polar solvents, ranging from 34.300±1.784 to 121.015±6.839 for A. indica ethyl acetate and methanolic extracts. A strong correlation between TPC and tannic acid content was observed, except in A. indica methanolic extracts of A. indica. Ferric reducing power was high, except for V. amygdalina chloroform and methanol leaf extracts, which were lower (P≤ 0.05) than that of the standard ascorbic acid. The study revealed that high polar solvents, such as methanol and water, are more efficient in the extraction of antioxidants from A. indica but lower in V. amygdalina extracts. High phytochemical content and antioxidative capacity could be significant in treating various diseases in humans.

Selective Extraction Process and Characterization of Antioxidant Phenolic Compounds from Pereskia aculeata Leaves Using UPLC-ESI-Q-TOF-MS/MS.

This study innovates in comparing biological activities and chemical composition obtained from extracts and fractions from Pereskia aculeate leaves. Seven extracts and five fractions were produced by conventional successive solid-liquid extraction coupled with simultaneous bioguided purification using solvents of distinct polarities. A comparative analysis was conducted between these purified fractions and the original extracts to elucidate potential improvements in the bioactivity. The extract and fractions were evaluated using the ABTS, DPPH, FRAP, and Folin-Ciocalteau methods and HPLC-DAD and UHPLC-ESI-Q-TOF-MS/MS evaluated chemical composition. The fractions obtained from the hydroalcoholic extract showed better results, with the acetone fraction (Fr-Ace) exhibiting enhanced bioactivity, especially in the FRAP (1095 μmol of FeSO4/g) antioxidant capacity method. The results demonstrated that medium to high polarity solvents were the most effective in extracting bioactive phenolic compounds, with rutin being the predominant compound. The sequential hydroalcoholic fractionation (SHF) method extracted a greater variety of compounds, including vanillic acid and cinnamic acid, which were reported for the first time in P. aculeate leaves. The identified compounds by UPLC-Q-TOF-MS/MS included flavonoids derived from quercetin, isorhamnetin, and kaempferol, phenolic acids, and their derivatives. Quercetin-3-O-xyloside, kaempferol-3-O-arabinoside, trehalose, feruloyltyramine, malyngic acid, pinellic acid, and 16-hydroxy-9-oxooctadeca-10,12,14-trienoic acid were identified for the first time in P. aculeata leaves.

Synthesis of a new unnatural polysaccharide, 2-deoxy-β(1→3)-glucan, by β−1,3-glucan phosphorylase-catalyzed enzymatic polymerization

Abstract We successfully synthesized a new unnatural polysaccharide, 2-deoxy-β(1→3)-glucan, by β−1,3-glucan phosphorylase-catalyzed enzymatic polymerization of a D-glucal monomer from a cellobiose primer, owing to recognition of such non-native substrates by the enzyme. Because of solubility of the product in several high polar organic solvents, acetylation as an example of its derivatizations smoothly occurred using acetic anhydride in the presence of base/catalyst in a DMF solvent. The NMR analysis of the acetylated derivative strongly supported the β(1→3)-linked chain structure.

Naphthalimide Based Fluorophore for the Detection of Hazardous Volatile Organic Compounds (VOCs).

The naphthalimide molecule (NAP) was successfully synthesized and characterized by spectroscopy techniques. The NAP probe was exposed to a solvatochromic and aggregation-induced emission (AIE) probe using UV-visible and PL spectroscopy. In this case, the increased polarity of the solvent shows that it is red-shifted. The probe emission, a sky blue to yellow-green color at hexane to DCM, exhibited an excellent quantum yield. Meanwhile, the high-polar solvents of DMF and DMSO had poor quantum yields. This probe NAP showed the aggregation-induced emission property dramatically enhanced the emissions (at 540nm) from fw = 80-90%. NAP was conducted with two polar solvent vapors in hexane and chloroform to investigate VOCs in a further solid-state study. A real-life test paper kit NAP probe was prepared and investigated VOCs detection against hexane and chloroform. When exposed to hexane vapors, the NAP probe test kit showed sky blue emission under UV light, which returned to greenish emission upon exposure to chloroform. Therefore, the results show that this NAP probe can be used for gas leak detection applications.

Lipid droplets-specific fluorescent probe for wash-free imaging and in vivo diagnosis of non-alcoholic fatty liver disease.

Lipid droplets (LDs) dysfunction is closely associated with a multitude of diseases, including nonalcoholic fatty liver disease (NAFLD). Therefore, it is imperative to develop fluorescent probes that specifically target LDs for the early detection and diagnosis of NAFLD. In this study, a series of lipophilic fluorophoresCZ1-CZ4 that feature a D-π-A configuration were designed and synthesized based on the carbazole and tricocyanofuran derivatives. The photophysical data revealed that all four probes exhibited large Stokes shifts (~ 120nm) in high-polarity solvents (e.g., DMSO) and demonstrated enhanced fluorescence in solvents ranging from low-polarity (e.g., 1,4-Dioxane) to high-polarity. Notably, by utilizing probeCZ1, we could specifically visualize LDs and captured high-quality images, even eliminating the need for a time-consuming wash procedure. Moreover,CZ1 enabled monitoring of LDs dynamic changes in-real time within live cells, and importantly, it could be used to effectively distinguish normal and NAFLD tissues at both the organ and in vivo level. This exceptional property of probeCZ1 provides a practical tool for the diagnosis and intervention of NAFLD.

Antibacterial Activity and Phytochemical Analysis of Moringa oleifera Extract against Staphylococcus aureus Identified by Routine and Molecular Methods

Abstract Background: Many diseases caused by bacterial and viral infections may now be treated using herbal extracts instead of chemical drugs. Objectives: This study aimed to investigate the antibacterial effect of Moringa oleifera leaf extracts against the bacterium employed in the experiment, as a commensal. Staphylococcus aureus can be found on the skin and in the nasal flora. It can also cause invasive, localized illnesses. Many virulence factors are present in S. aureus. It is recognized by routine and molecular methods depending on Vick Staphylococcal gene. Material and Methods: Phytochemical analysis of high polarity solvent leaves was done by using ethanol. Phytochemical study revealed the presence of tannins, alkaloids, flavonoids, steroids, saponins, and other compounds in the extract. Using the well-diffusion method, the antibacterial effect of the extracts on microorganisms was investigated. Results: The ethanol extract proved potent against pathogenic microorganisms, with S. aureus showing the highest activity (10–100 mg/mL). In comparison to the concentrations of alcoholic extracts, the zones’ inhibition of bacterial growth in diameters increased. However, dosages of 80–100 mg/mL were highly effective and significant against S. aureus growth, whereas concentrations of 10–20 mg/mL had low post-detected efficiency and concentrations of 40–60 mg/mL had medium post-detected efficiency. Conclusion: These studies demonstrate the validity of the plant’s traditional medicinal properties.

Solvation model effects on the static first hyperpolarizability of a push–pull π‐conjugated molecule

AbstractIn this work, we presented the results of density functional theory calculations for the static first hyperpolarizability for one representative push–pull π‐conjugated molecule, 2‐dimethylamino‐7‐nitrofluorene, in six organic solvents (p‐dioxane, chloroform, tetrahydrofuran, acetone, acetonitrile, and dimethylsulfoxide) spanning a large range of dielectric constant. The finite‐field formalism was used to calculate the longitudinal component of the static first hyperpolarizability. The solvent effect was calculated using two distinct polarizable continuum solvation models: the linear response and the state‐specific polarizable continuum models. The calculations demonstrated the existence of solvation model effects on the property of interest, which warranted further analysis. The two‐level model was then employed to illustrate the impact of solvation model. Our findings suggested that the state‐specific polarizable continuum model gave a decrease of the dipole moment of the excited state in high polarity solvent for a bathochromic molecule whose excited state should have a larger polarization than its ground state.

Switchable Dual Circularly Polarized Luminescence in Through-Space Conjugated Chiral Foldamers.

Organic materials with switchable dual circularly polarized luminescence (CPL) are highly desired because they can not only directly radiate tunable circularly polarized light themselves but also induce CPL for guests by providing a chiral environment in self-assembled structures or serving as the hosts for energy transfer systems. However, most organic molecules only exhibit single CPL and it remains challenging to develop organic molecules with dual CPL. Herein, novel through-space conjugated chiral foldamers are constructed by attaching two biphenyl arms to the 9,10-positions of phenanthrene, and switchable dual CPL with opposite signs at different emission wavelengths are successfully realized in the foldamers containing high-polarizability substitutes (cyano, methylthiol and methylsulfonyl). The combined experimental and computational results demonstrate that the intramolecular through-space conjugation has significant contributions to stabilizing the folded conformations. Upon photoexcitation in high-polar solvents, strong interactions between the biphenyl arms substituted with cyano, methylthio or methylsulfonyl and the polar environment induce conformation transformation for the foldamers, resulting in two transformable secondary structures of opposite chirality, accounting for the dual CPL with opposite signs. These findings highlight the important influence of the secondary structures on the chiroptical property of the foldamers and pave a new avenue towards efficient and tunable dual CPL materials.

Elucidating solvent effects on lipase-catalyzed peroxyacid synthesis through activity-based kinetics and molecular dynamics.

Peroxyacid synthesis is the first step in Prilezhaev epoxidation, which is an industrial method to form epoxides. Motivated by the development of a kinetic model as a tool for solvent selection, the effect of solvent type and acid chain length on the lipase-catalyzed peroxyacid synthesis was studied. A thermodynamic activity-based ping-pong kinetic expression was successfully applied to predict the effect of the reagent loadings in hexane. The activity-based reaction quotients provided a prediction of solvent-independent equilibrium constants. However, this strategy did not achieve satisfactory estimations of initial rates in solvents of higher polarity. The lack of compliance with some assumptions of this methodology could be confirmed through molecular dynamics calculations i.e. independent solvation energies and lack of solvent interaction with the active site. A novel approach is proposed combining the activity-based kinetic expression and the free binding energy of the solvent with the active site to predict kinetics upon solvent change. Di-isopropyl ether generated a strong interaction with the enzyme's active site, which was detrimental to kinetics. On the other hand, toluene or limonene gave moderate interaction with the active site rendering improved catalytic yield compared with less polar solvents, a finding sharpened when peroctanoic acid was produced.

Study on An Interaction between Titan Yellow and Orange S Indicators in Water and Ethanol by using Spectroscopy Technique

Charge transfer complex (CTC) of Orange S (donor) and Titan Yellow (acceptor) has been studied in ethanol, and water solvents at room temperature (20°C) using absorption spectrophotometer. The results indicate that formation of CTC in high polar solvent is high. The stoichiometry of the complex was found to be 1:1 ratio by straight-line method between donor and acceptor with maximum absorption bands and present of isosbestic point suggest this fact. The data are discussed in terms of formation constant (KCT), molar extinction coefficient (εCT), standard free energy (ΔGo), transition energy (ECT), and ionization potential (IP). The formation constant (KCT) for the complex was shown to be dependent upon the polarity of solvents that were used. Electronic absorption spectra, which indicate the CT interaction, associated with proton migration from the acceptor to the donor followed by hydrogen bonding.

Supramolecular Gels Based on C3-Symmetric Amides: Application in Anion-Sensing and Removal of Dyes from Water.

We modified C3-symmetric benzene-1,3,5-tris-amide (BTA) by introducing flexible linkers in order to generate an N-centered BTA (N-BTA) molecule. The N-BTA compound formed gels in alcohols and aqueous mixtures of high-polar solvents. Rheological studies showed that the DMSO/water (1:1, v/v) gels were mechanically stronger compared to other gels, and a similar trend was observed for thermal stability. Powder X-ray analysis of the xerogel obtained from various aqueous gels revealed that the packing modes of the gelators in these systems were similar. The stimuli-responsive properties of the N-BTA towards sodium/potassium salts indicated that the gel network collapsed in the presence of more nucleophilic anions such as cyanide, fluoride, and chloride salts at the MGC, but the gel network was intact when in contact with nitrate, sulphate, acetate, bromide, and iodide salts, indicating the anion-responsive properties of N-BTA gels. Anion-induced gel formation was observed for less nucleophilic anions below the MGC of N-BTA. The ability of N-BTA gels to act as an adsorbent for hazardous anionic and cationic dyes in water was evaluated. The results indicated that the ethanolic gels of N-BTA successfully absorbed methylene blue and methyl orange dyes from water. This work demonstrates the potential of the N-BTA gelator to act as a stimuli-responsive material and a promising candidate for water purification.

Solvatochromic fluorescent ethynyl naphthalimide derivatives for detection of water in organic solvents

Three new derivatives of (4-methoxyphenyl) ethynyl-naphthalimide were synthesized by Sonogashira coupling reaction. These compounds showed robust and strong fluorescent signals, which shift from blue to orange as the solvent polarity increases. Computational calculations revealed that in low-polarity solvents, the molecules preferred a 90° rotation between the naphthalimide and ethynyl benzene fragments. In high-polarity solvents, where the energy barrier for rotation of the alkyne bond was higher, the molecules favored the 0° conformer, leading to longer emission wavelengths. The compound with a 2-methoxyethyl group tethered to the naphthalimide nitrogen demonstrated sensitivity to water presence in the ranges of 0–30 % (v/v) in THF, 0–15 % (v/v) in DMSO, 0–30 % (v/v) in MeCN, 0–15 % (v/v) in acetone, and 0–40 % (v/v) in EtOH. The detection limits for water were determined to be 0.0523 %, 0.1365 %, 0.0337 %, 0.0570 %, and 0.1170 % (v/v) in THF, DMSO, MeCN, acetone, and EtOH, respectively. The effectiveness of this compound in quantifying ethanol content in spirit samples was successfully demonstrated.

Development of a chromatographic method for optimizing the thiol-maleimide coupling of polyoxometalate-polymer hybrids

The covalent attachment of polyoxometalates (POMs) to polymers has been developed as a strategic approach for the advancement of POM-based hybrid materials with versatile applications. In this study, we utilized thiol-maleimide Michael addition to investigate the kinetics and efficacy of the “one-to-one” conjugation between Keggin type POM and polystyrene. We explored the effects of solvent polarity, catalyst, molecular weight of PS and synthetic strategies on the reaction kinetics and efficiency, by means of reverse-phase high-performance liquid chromatography (RP-HPLC). A series of comparative analysis affirmed the superior efficiency of the one-pot method, particularly when facilitated by the addition of a high-polarity solvent and an excess of maleimide. These findings offer valuable insights into the intricate interplay between reaction conditions, kinetics, and selectivity in thiol-maleimide reactions of POMs and polymers. They hold profound implications for advancing the study of POM-based multifunctional materials and the synthesis of complex hybrid molecules.

Highly luminescent CsPbX3@MIL-53(Al) nanoarchitectonics with anomalous stability towards flexible emitting films

The poor stability of perovskite nanomaterials exposed in high temperature, moisture, light radiation, and polar solvent conditions severely restrict their commercial application. To address this issue, the growth in situ of CsPbX3 (X = Cl, Br, I) nanocrystals (NCs) is carried out by using the stable aluminum (Al)-based metal-organic frameworks to create CsPbX3@MIL-53(Al) composites. Compared with pristine CsPbX3 NCs prepared using room temperature ligand assisted re-precipitation synthesis, the CsPbX3@MIL-53(Al) composites exhibit narrow photoluminescence (PL) spectra and greatly improved stability. The green emitting CsPbBr3@MIL-53(Al) composite exhibit narrowed PL spectrum (the full width at half-maximum of PL spectra: 20 nm for the composite and 28 nm for CsPbBr3 NCs) and a blue-shifted PL peak wavelength (517.6 nm for the composite and 527.6 nm for the CsPbBr3 NCs). The relationship of microstructure, components, PL, fluorescence lifetime, and stability are discussed systematically. Anomalous stability against heat-treatment, polar solvent and humidity conditions indicated the composites retained their initial PL intensity after storge more than 4 months in ambient conditions and heat-treated to 120ºC for 5 cycles. The emitting color of CsPbBr3@MIL-53(Al) composites are easily adjusted from blue, green to red by controlling the halide components of precursors. The composite was used to create emitting coating and highly bright flexible emitting films which also reveal high stability, suggesting that in situ encapsulation of CsPbX3 NCs in MIL-53(Al) would supply a novel platform for various emitting devices.