Microporous Network Research Articles

Construction of cyclodextrin microporous organic network based drug delivery platform for controllable release and targeting delivery of doxorubicin

Rational design and fabrication of effective drug delivery systems (DDS) are crucial for improving the therapeutic effectiveness and overcoming the shortcomings of chemotherapy. Herein, we report the construction of a novel cyclodextrin microporous organic network (CD-MON)-based DDS via a convenient thiol‑yne click reaction and dehydration condensation modification for the controllable release and targeted delivery of doxorubicin (DOX), a typical chemotherapy drug. The constructed DDS afforded multiple hydrophobic, hydrogen-bonding, and host-guest interaction sites, allowing for the efficient loading of DOX. The obtained DDS also exhibited good sustained and long-term release of DOX. Additionally, the proposed DDS offers good biocompatibility and exhibits an obvious aggregation-induced emission. Furthermore, the introduction of folic acid (FA) into the CD-MON-based DDS provided excellent targeting capacity for FA receptor-positive NCI-H226 cells. This study proved the universality of the design, synthesis, and application of CD-MON-based DDS, revealing the great potential of CD-MONs in drug delivery.

Using Excimer Laser for Manufacturing Stimuli Responsive Membranes.

A 248 nm KrF excimer laser can be used to manufacture temperature and pH-responsive polymer-based membranes for controlled transport applications. This is done by a two-step approach. In the first step, well-defined/shaped and orderly pores are created on commercially available polymer films by ablation by using an excimer laser. The same laser is used subsequently for energetic grafting and polymerization of a responsive hydrogel polymer inside the pores fabricated during the first step. Thus, these smart membranes allow controllable solute transport. In this paper, determination of appropriate laser parameters and grafting solution characteristics are illustrated to obtain the desired membrane performance. Fabrication of membranes with 600 nm to 25 μm pore sizes by using the laser through different metal mesh templates is discussed first. Laser fluence and the number of pulses need to be optimized to obtain the desired pore size. Mesh size and film thickness primarily control the pore sizes. Typically, pore size increases with increasing fluence and the number of pulses. Larger pores can be created by using higher fluence at a given laser energy. The vertical cross-section of the pores turns out to be inherently tapered due to the ablative action of the laser beam. The pores created by laser ablation can be grafted with PNIPAM hydrogel by using the same laser to perform a bottom-up grafting-from type pulsed laser polymerization (PLP) in order to achieve the desired transport function controlled by temperature. For this purpose, a set of laser frequencies and pulse numbers need to be determined to obtain the desired hydrogel grafting density and the extent of cross-linking, which ultimately provide controlled transport by smart gating. In other words, on-demand switchable solute release rates can be achieved by controlling the cross-linking level of the microporous PNIPAM network. The PLP process is extremely fast (few seconds) and provides higher water permeability above the lower critical solution temperature (LCST) of the hydrogel. Experiments have shown high mechanical integrity for these pore-filled membranes, which can sustain pressures up to 0.31 MPa. The monomer (NIPAM) and cross-linker (mBAAm) concentrations in the grafting solution need to be optimized in order to control the network growth inside the support membrane pores. The cross-linker concentration typically has a stronger effect on the temperature responsiveness. The pulsed laser polymerization process described can be extended to different unsaturated monomers, which can be polymerized by the free radical process. For example, poly(acrylic acid) can be the grafted to provide pH responsiveness to membranes. As for the effects of thickness, a decreasing trend is observed in the permeability coefficient with increasing thickness. Furthermore, the film thickness has little or no effect on PLP kinetics. The experimental results have shown that membranes manufactured by excimer laser are excellent choices for applications where flow uniformity is the prime requirement, as they possess uniform pore sizes and distribution.

Hollow-structured molecularly imprinted polymers enabled specific enrichment and highly sensitive determination of aflatoxin B1 and sterigmatocystin against complex sample matrix

The biotoxins with high toxicity have the potential to be manufactured into biochemical weapons, seriously threatening international public security. Developing robust and applicable sample pretreatment platforms and reliable quantification methods has been recognized as the most promising and practical approach to solving these problems. Through the integration of the hollow-structured microporous organic networks (HMONs) as the imprinting carriers, we proposed a molecular imprinting platform (HMON@MIP) with enhanced adsorption performance in terms of specificity, imprinting cavity density as well as adsorption capacity. The HMONs core of MIPs provided a hydrophobic surface that enhanced the adsorption of biotoxin template molecules during the imprinting process, resulting in an increased imprinting cavity density. The HMON@MIP adsorption platform could produce a series of MIP adsorbents by changing the biotoxin template, such as aflatoxin and sterigmatocystin, and showed promising generalizability. The limits of detection (LOD) of the HMON@MIP-based preconcentration method for AFT B1 and ST were 4.4 and 6.7 ng L−1, respectively, and the method was applicable to food sample with satisfied recoveries of 81.2–95.1%. And the specific recognition and adsorption sites left on HMON@MIP by the imprinting process can achieve outstanding selectivity for AFT B1 and ST. The developed imprinting platforms hold great potential for application in the identification and determination of various food hazards in complex food sample matrices and contribute to precise food safety inspection.

Nano-Fe3O4 coated on carbon monolith for anode enhancement in microbial fuel cells

Anode materials were vital for power production in microbial fuel cells (MFCs). By freeze-drying and carbonization, porous carbon monolith derived from wax gourd (WGCM) was prepared. WGCM was then coated by nano-Fe3O4 to obtain the nano-Fe3O4/WGCM anode. WGCM anode increased the maximum power density of the MFCs from 430.6 mW/m2 to 906.6 mW/m2, while nano-Fe3O4/WGCM anode further promoted it to 1438.8 mW/m2. WGCM had a three-dimensional (3D) microporous network structure, a hydrophilic surface and good conductivity, which enhanced biofilm formation and reduced internal resistance. Fe3O4 increased Geobacter enrichment on anode surface, a popular electricigen in MFCs. Calculated from anode surface microbial cell density and the relative abundance, Geobacter on the nano-Fe3O4/WGCM increased by 41.4% compared with the WGCM anode. The results demonstrated that the preparation of carbon monolith coated with nano-Fe3O4 was a promising method for anode enhancement in MFCs.

A Molecular Insight into the Dehydration of a Metal-Organic Framework and its Impact on the CO2 Capture.

Metal-organic frameworks (MOFs) are porous material formed by the self-assembly of metallic ligands and organic linkers. They are a good candidate for CO2 gas capture because they have large surface areas and the metal or linker can be tuned to improve CO2 uptake. In the quest for water and acid stable MOFs, a phosphonate-based organic linker has recently been designed by Glavinovic et al. (Chem. Eur. J. 2022, 28, e202200874). By combining ionic calcium nodes, water and methanol molecules, they formed a microporous network, CALF-37. This network has been shown to be robust and can maintain its pore shape even in absence of water molecules or by the inclusion of gas molecules, such as CO2 . The network can be heated to release the water and methanol molecules and form a dehydrated MOF, which retains its shape with the imprinted pore within. Herein, we perform molecular dynamics (MD) simulations in order to provide insight into the CO2 capture and sequestration ability of the CALF-37. We model the dehydration of the inactivated MOF (HCALF-37) in the absence and in the presence of methanol molecules by progressively withdrawing water molecules from the MOF networks. We determine the crystal structure of the intermediate states from HCALF-37 to CALF-37 and shed light on the critical role of water molecules in the mediation of metal-linker bonds. Our calculations also reveal that the favorable interactions between the CO2 molecules and the aromatic core of the linkers and metallic ions are responsible for the efficient sequestration of the gas in the CALF-37.

Microporous melamine-formaldehyde networks loaded on rice husks for dynamic removal of organic micropollutants

The alteration of agricultural wastes into novel adsorbents can stimulate their scalability in realistic application, showing great economic and environmental advantages. Here, we proposed a strategy to engineer rice husk (RH) with microporous melamine-formaldehyde networks (MFNs) resins and the utilization for dynamic removal of organic micropollutants rapidly and efficiently. was pre-treated to acquire attractive surface and unique hierarchical porosity, endowing with surface functionalization and essential filtering properties. MFNs can be uniformly generated in-situ on the fully exposed cellulose backbones of the pre-treated RH. MFNs granules functionalized RH (RH@MFNs) exhibited high removal efficiencies over 90% within 30 min for the adsorption of hazardous organic compounds (e.g., phenolic and antibiotic micropollutants) in static tests. Experiment results and density functional theory (DFT) simulation revealed that the synergy of hydrogen bonding, π-πinteraction, and micropore preservation dominates the adsorption. Further dynamic adsorption experiments showed that the removal efficiency and equilibrium removal capacity towards bisphenol A by RH@MFNs packed bed up-flow column were 2.6 and 67 times higher than that of raw RH, respectively. The column adsorption fits well with the Thomas model and bed depth service time (BDST) kinetic model. The inherent macropores inside RH and the roughness caused by the spiky structures and mesopores outside RH, as well as the accumulated MFNs granules, can lead to local turbulence of water flow around RH@MFNs, enabling fast and efficient adsorption. This sustainable and cost-effective preparation of RH-based adsorbents sheds light on the rational design of biomass waste adsorbents for realistic wastewater.

Synthesis of crown ether-based microporous organic networks: A new type of efficient adsorbents for chlorophenols.

Microporous organic networks (MONs) are a booming class of functional materials in elimination of environmental pollutants. However, the limit varieties of MONs still restrict their broad applications. Here we report the synthesis of a novel type of crown ether (CE)-based MONs via the coupling between brominated 18-crown-6 ether and different aromatic alkynyls. The constructed CE-based MONs integrates the good conjugation property of MONs and the inherent host-guest binding sites of CE, allowing the ultrafast and efficient adsorption and removal of a typical environmental priority pollutant 2,4,6-trichlorophenol (2,4,6-TCP). The hydrophobic CE-based MONs can also address the recovery challenge of unstable discrete CE in most organic and inorganic solvents. All CE-based MONs displayed fast adsorption kinetics (< 3min) and large adsorption capacities (229.1-341.7mgg-1) for 2,4,6-TCP. The CE-based MONs also gave stable adsorption capacities for 2,4,6-TCP in pH range of 4.0-6.0, NaCl concentration of 0-40mgL-1, HA concentration of 0-30mgL-1, or H2O2 ratio of <5%. Density functional theory calculation, Fourier transform infrared and X-ray photoelectron spectra evaluation revealed adsorption process involved hydrophobic, π-π and hydrogen bonding interactions. The CE-based MONs also showed favorable reusability and good adsorption for other toxic chlorophenols. This work highlights the potential of CE-based MONs in contaminants elimination.

Combining Polymerization and Templating toward Hyper-Cross-Linked Poly(propargyl aldehyde)s and Poly(propargyl alcohol)s for Reversible H2O and CO2 Capture and Construction of Porous Chiral Networks.

Two series of hyper-cross-linked microporous polyacetylene networks containing either -[CH=C(CH=O)]- or -[CH=C(CH2OH)]- monomeric units are reported. Networks are prepared by chain-growth copolymerization of acetal-protected propargyl aldehyde and acetal-protected propargyl alcohol with a 1,3,5-triethynylbenzene cross-linker followed by hydrolytic deprotection/detemplating. Deprotection not only liberates reactive CH=O and CH2OH groups in the networks but also modifies the texture of the networks towards higher microporosity and higher specific surface area. The final networks with CH=O and CH2OH groups attached directly to the polyene main chains of the networks have a specific surface area from 400 to 800 m2/g and contain functional groups in a high amount, up to 9.6 mmol/g. The CH=O and CH2OH groups in the networks serve as active centres for the reversible capture of CO2 and water vapour. The water vapour capture capacities of the networks (up to 445 mg/g at 297 K) are among the highest values reported for porous polymers, making these materials promising for cyclic water harvesting from the air. Covalent modification of the networks with (R)-(+)-3-aminopyrrolidine and (S)-(+)-2-methylbutyric acid enables the preparation of porous chiral networks and shows networks with CH=O and CH2OH groups as reactive supports suitable for the anchoring of various functional molecules.

Laminar MoS2 Nanosheets Embedded into Organosilica Membranes for Efficient H2 Separation

Two-dimensional (2D) molybdenum disulfide (MoS2) with a unique action on H2 was incorporated into 1,2-bis(triethoxysilyl)ethane (BTESE)-derived bridged microporous organosilica networks to form a composite membrane for H2 separation by a sol–gel method. Due to their opposite ζ-potentials, a continuous surface without lamellar boundary defects was formed between BTESE sols derived by the hydrolysis–polymerization reaction and MoS2 nanosheets. When the MoS2 content increased in BTESE networks, the H2 permeance showed an overall increasing trend in the range of 1.85–2.89 × 10–7 mol·m–2 s–1 Pa–1 (552–864 GPU), which was higher than that of pristine BTESE membrane with the H2 permeance of 491 GPU. In addition, optimized MoS2/BTESE membranes showed a much higher H2/N2 permselectivity of 129 than that of the pristine BTESE membrane of 17 at 100 °C. The synergistic effect of BTESE and MoS2 nanosheets plays an important role. Through adsorption isotherm test and diffusivity as well as energy calculation, BTESE networks became denser by nonporous MoS2 addition that prevented N2 from passing, while H2 was promoted with excellent adsorption on charged edges of MoS2, resulting in improved H2 separation performance both in permeance and selectivity. This provides an attractive mechanism for hydrogen separation.

Truchet-tile structure of a topologically aperiodic metal-organic framework.

When tiles decorated to lower their symmetry are joined together, they can form aperiodic and labyrinthine patterns. Such Truchet tilings offer an efficient mechanism of visual data storage related to that used in barcodes and QR codes. We show that the crystalline metal-organic framework [OZn4][1,3-benzenedicarboxylate]3 (TRUMOF-1) is an atomic-scale realization of a complex three-dimensional Truchet tiling. Its crystal structure consists of a periodically arranged assembly of identical zinc-containing clusters connected uniformly in a well-defined but disordered fashion to give a topologically aperiodic microporous network. We suggest that this unusual structure emerges as a consequence of geometric frustration in the chemical building units from which it is assembled.

The fabrication of Pt–Pb alloy networks with high-density micropores by dealloying for enhanced oxygen reduction activity

Porous Pt-based nanomaterials possess intriguing properties for various important applications due to their abundant exposed active sites and highly accessible surfaces. Importantly, the pore size is a key factor that determines its specific applicability. With the advances of fabrication strategies, Pt-based nanomaterials with a variety of unique pore structure including mesopores and macropores have been extensive reported. However, so far, few effective methods have been reported to prepare the Pt-based nanomaterials with high-density micropores. In this work, we reported a facile method to prepare the high-density microporous Pt–Pb NWs via a chemical etching strategy by using the intermetallic PtPb networks (NWs) as the starting material. After dealloying, a large amount of microporous and defects were successfully introduced into the MP-PtPb NWs. The microporous networks can not only increase the active area both on the exterior and interior surface, but also provide efficient mass transfer and electron mobility for reactant molecules. As a result, the mass activity exhibited by MP-PtPb NWs catalyst is 0.83 A mg−1Pt, which is 5.8 and 1.9 times than that of commercial Pt/C and IM-PtPb NWs. Besides, even after 10,000 cycles of accelerated durability test, the MP-PtPb NWs and IM-PtPb NWs exhibit comparable drop of ∼10% in mass activity, against a big decrease of 46% for commercial Pt/C. We believe this work provides an efficient strategy to prepare metallic catalysts with high-density microporous nanomaterials for catalysis.

Facile synthesis of triazine-based microporous organic network for high-efficient adsorption of flumequine and nadifloxacin: A comprehensive study on adsorption mechanisms and practical application potentials

Flumequine (FLU) and nadifloxacin (NAD), as emerging contaminants, have received extensive attention recently. In this study, a triazine-based microporous organic network (TMON) was synthetized and developed as an excellent adsorbent for FLU and NAD. The adsorption behavior and influence factors were investigated in both single and binary systems. Insight into the adsorption mechanisms were conducted through experiments, models, and computational studies, from macro and micro perspectives including functional groups, adsorption sites, adsorption energy and frontier molecular orbital. The results showed that the maximum adsorption capacities of TMON for FLU and NAD are 325.27 and 302.28 mg/g under 30 °C higher than records reported before. TMON exhibits the better adaptability and anti-interference ability for influence factors, leading to the preferable application effect in kinds of real water samples. TMON also shows the application potentials for the adsorption of other quinolone antibiotics and CO2 capture. Hydrogen-bonding interaction played the most critical role compared to π-π stacking effect, π-π electron-donor-acceptor interaction, CH-π interaction, and hydrophobic interaction during the adsorption. TMON could be regarded as a promising environmental adsorbent for its large surface area, stable physical and chemical properties, excellent recyclability, and wide range of applications.

Ultrafast ultrasound-assisted synthesis of microporous organic networks for the efficient removal of antibiotics

A novel green ultrasound-assisted method was proposed for ultrafast, convenient, and efficient synthesis of MONs for effective removal of antibiotics.

Photochemical and gas adsorption studies of Keggin polyoxometalate functionalized porous melamine terephthaldehyde material.

A compound containing a microporous melamine-terephthaldehyde framework is protonated by grinding with acetic acid, resulting in a mesoporous protonated melamine-terephthaldehyde network. The Keggin polyanion [PMo12O40]3- is then immobilized into this protonated melamine-terephthaldehyde network through a solid-state reaction. The polyanion interacts with the protonated microporous organic network through electrostatic interaction. Three different Keggin-melamine-terephthaldehyde materials were synthesized by varying the Keggin anion loading of 10 wt%, 15 wt% and 20 wt%. The Keggin-melamine-terephthaldehyde materials exhibit photochromism on irradiation with sunlight. The photochromism of the POM-organic hybrid material is due to reduction of the Keggin anion. The resulting blue reduced Keggin-melamine-terephthaldehyde materials are oxidized back by treatment with hydrogen peroxide. The N2, CO2 and H2 adsorption properties of all the synthesized materials, including protonated melamine-terephthaldehyde materials, were studied. The materials were characterized by IR, PXRD, DRS, TGA, EPR spectroscopy, and FESEM electron microscopy. The elemental composition was analysed with a CHN analyser and ICP-OES analysis.

Phase transitions in alumina films during post-sparking anodising of Al alloys

Formation of the high-temperature α-Al2O3 phase during Plasma Electrolytic Oxidation of aluminium at ambient bulk temperatures has been previously attributed to local microdischarge events providing multiple melting-solidification cycles in micro-volumes of the surface oxide layer. In this work, it is demonstrated that the α phase can be formed even if the microdischarge is fully suppressed under specific processing conditions. Oxide layers produced in the post-sparking anodising mode were studied by FIB, TEM, EBSD, EDS and GDOES techniques to reveal microstructural and chemical evolutions that accompany the γ to α alumina transition. Our results provide strong evidence that the α phase can form spontaneously in regions of oxide with the appropriate temperature, grain size and impurity distributions in the γ-Al2O3 matrix that allow sufficient mobility of α/γ grain boundaries. Ionic migration within the oxide and hydrothermal dissolution/precipitation in the associated microporous network that facilitate species mobility at the grain boundaries allow the critical temperature for activation of γ→α transition to be reduced. Overall, it is suggested that oxide layer growth can be considered in terms of a relatively simple Plug Flow Reactor model. This can help predict the phase transition kinetics depending on key processing parameters such as current density and frequency of pulse polarisation, thus enabling optimum control of coating microstructure for specific application requirements.

Improved stability of β-carotene by encapsulation in SHMP-corn starch aerogels

This study aimed to prepare a starch-based aerogel with microporous network structure, and to investigate its physicochemical properties after β-carotene encapsulation. Corn starch aerogels (CSA) prepared with sodium hexametaphosphate (SHMP) as a cross-linking agent and β-carotene encapsulation were evaluated in terms of morphology, long- and short-range molecular order, bioavailability, and stability. After encapsulating β-carotene, the morphology of SHMP-CSA showed that the aerogels presented agglomeration, and the relative crystallinity increased from 17.2% to 22.2%. The characteristic bands of β-carotene were not found in the FT-IR pattern, and the short-range molecular order of aerogel was decreased, proving that β-carotene was well embedded in the aerogel. During the simulated in vitro release process, β-carotene was almost completely released. After ultraviolet or light irradiation, the retention rate of β-carotene was much higher than that in the control group. These results demonstrated that SHMP-CSA encapsulation could effectively improve the stability of β-carotene.

Epitaxial growth of surface-passivated core-shell ferrierite

Ferrierite (FER) is both a natural and synthetic zeolite that is commonly utilized as a catalyst in commercial processes that take advantage of its two-dimensional network of micropores. The external surfaces of zeolite crystals often impose deleterious effects on catalyst performance, such as external coking or unselective reactions as a result of unconfined acid sites. One technique that can improve the efficiency of zeolite catalysts is surface passivation wherein the aluminosilicate crystal is encapsulated within a shell of its siliceous isostructure. These core–shell configurations eliminate surface acidity, forcing reactions to occur within interior (confined) pores for improved shape-selectivity while simultaneously reducing rates of deactivation, which extends catalyst lifetime. In this study, we examine whether a Si-rich shell can be epitaxially grown on the surface of an aluminosilicate FER crystal in fluoride-free media. Epitaxial growth of an ultra-thin Si-rich shell was confirmed by multiple characterization techniques showing no evidence of pore blockage or misoriented shell growth during core–shell synthesis. The passivation of external acid sites was confirmed using Friedel-Crafts alkylation of mesitylene and benzyl alcohol as a benchmark reaction for probing surface acidity. Overall, these findings confirm that it is possible to synthesize core–shell ferrierite with an aluminosilicate core and a silicon-rich shell via a facile seed-assisted growth procedure.

Polymorphism from a 1:1 Ln:BTB reaction pot: Solvothermal versus sonochemical synthesis of Ln-MOFs

A 1:1 reaction pot of lanthanide(III):1,3,5-benzenetrisbenzoate (Ln(III):BTB) in a 2:1 mixture of DMF/H2O was subject to solvothermal and sonochemical conditions in order to form new Ln-BTB polymorphs. Solvothermal crystal growth is time dependent, yielding a new MOF structure Nd4(BTB)4(H2O)10•(H2O)7 (1) after 1–2 days and two new analogues of Ln(BTB)(H2O), Nd(BTB)(H2O) (2) and Sm(BTB)(H2O) (3) after 3.5 days. Sonochemical synthesis produced a pure phase of Ln(BTB)(H2O)2•(H2O)2(DMF)3 (4–7, Ln = Nd3+ (4), Eu3+ (5), Tb3+ (6), and Er3+ (7)). Compound 1 is a novel 3-D framework that consists of undulating one-dimensional lanthanide-carboxylate secondary building unit (SBU) chains connected by BTB linkers, which pack into a hxl topology with rhombohedral and hexagonal channels. The total solvent accessible void space is 4581.6 Å3 which constitutes 37 % of the of the total unit cell volume. Compounds 2 and 3 are three-dimensional microporous networks consisting of mutually parallel-perpendicular, infinite, undulating one-dimensional metal-carboxylate SBU chains interlinked by BTB ligands. Compounds 4–7 were previously reported from four different synthetic protocols and feature Ln2(COO)6(H2O)4 SBUs linked by BTB linkers into a two-dimensional (3,6-connected) kgd network, which assembles via hydrogen bonds into a three-dimensional supramolecular framework. Gas adsorption studies on compound 4 indicate microporous and mesoporous sites that contribute relatively high Langmuir and BET surface areas up to 1161 m2/g and 671 m2/g, respectively. Eu(BTB)(H2O)2•(H2O)2(DMF)3 (5) displays strong luminescence under UV excitation and is a highly sensitive and selective sensor for Fe3+ ions and nitroaromatic compounds. Sensing occurs via luminescence quenching due to competitive absorption of excitation energy between the BTB framework and the analyte molecules.

Temperature-Programmed Separation of Hexane Isomers by a Porous Calcium Chloranilate Metal-Organic Framework.

The full separation of alkane isomers as a function of different degrees of branching remains a daunting challenge due to its stringent requirement with respect to pore dimensions of the adsorbents. In this work, we report a novel microporous coordination network built on calcium (II) and chloranilate. The compound has a flexible framework and exhibits temperature-dependent adsorption behavior toward hexane isomers. At 30 °C, it accommodates substantial amounts of linear and monobranched hexanes but fully excludes their dibranched isomer, and at elevated temperatures such as 150 °C, it acts as a splitter for linear and branched alkanes. Its capability of efficient discrimination of hexane isomers as a function of branching is verified by experimental breakthrough measurements. Ab initio calculations have uncovered the underlying selective size-exclusion separation mechanism.

Temperature‐Programmed Separation of Hexane Isomers by a Porous Calcium Chloranilate Metal‐Organic Framework

AbstractThe full separation of alkane isomers as a function of different degrees of branching remains a daunting challenge due to its stringent requirement with respect to pore dimensions of the adsorbents. In this work, we report a novel microporous coordination network built on calcium (II) and chloranilate. The compound has a flexible framework and exhibits temperature‐dependent adsorption behavior toward hexane isomers. At 30 °C, it accommodates substantial amounts of linear and monobranched hexanes but fully excludes their dibranched isomer, and at elevated temperatures such as 150 °C, it acts as a splitter for linear and branched alkanes. Its capability of efficient discrimination of hexane isomers as a function of branching is verified by experimental breakthrough measurements. Ab initio calculations have uncovered the underlying selective size‐exclusion separation mechanism.