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. 2026 Sep 22. Online ahead of print. doi: 10.1039/d6sc05421h

Asymmetric recognition in metal–organic frameworks for enhanced ethylene/ethane sieving

Yanhui Dai a, Dongxiao Yang a, Lifei Yin a, Yi Wang a, Bangku Yang a, Yang Chen a,✉, Jinping Li b, Libo Li a,✉
PMCID: PMC13625846  PMID: 42820037

Abstract

Ethylene/ethane (C2H4/C2H6) separation is one of the most energy-intensive processes in the petrochemical industry, highlighting the urgent need for efficient adsorbents to replace cryogenic distillation. In this work, a new metal–organic framework (MOF), TYUT-25, is constructed via an asymmetric recognition strategy to achieve directional regulation of adsorption behavior within channels. In conventional systems, structural modulation typically induces a synchronous adsorption response, where C2H4 and C2H6 uptake increase or decrease simultaneously, thereby limiting further improvements in selectivity. In contrast, the asymmetric recognition strategy results in inverse adsorption behaviors of C2H4 and C2H6. The pore aperture is contracted to suppress C2H6 entry, thereby enabling size-sieving discrimination between C2H4 and C2H6, while the pore cavity enhances interactions between C2H4 and the framework, leading to enhanced C2H4 uptake and suppressed C2H6 adsorption. Compared with Zn(BPA)(BDC), adsorption measurements show that the C2H4 uptake of TYUT-25 increases from 1.6 to 8.4 cm3 g−1 at 0.1 bar and reaches 34.4 cm3 g−1 at 1 bar. At 298 K and 1 bar, the C2H4/C2H6 selectivity exceeds 104. Breakthrough experiments further verify separation performance. DFT calculations and Hirshfeld surface analysis indicate enhanced host–guest interactions. This work demonstrates that asymmetric recognition enables inverse adsorption responses, providing an effective strategy for the coordinated regulation of adsorption capacity and selectivity within a MOF.

Ethylene/ethane (C2H4/C2H6) separation is one of the most energy-intensive processes in the petrochemical industry, highlighting the urgent need for efficient adsorbents to replace cryogenic distillation.graphic file with name d6sc05421h-ga.webp

1. Introduction

Ethylene (C2H4) is one of the most widely produced chemicals worldwide and is commonly regarded as a key indicator of a nation's level of petrochemical development.1–3 With the rapid expansion of emerging industries and continuous advances in chemical technology, the demand for C2H4 based materials has grown substantially.4 As a result, global C2H4 production has surpassed 200 million tons per year. At present, high-purity C2H4 (≥99.5%) is mainly obtained through cryogenic distillation of steam cracking gases.5,6 This process represents one of the most energy-intensive operations in the chemical industry, accounting for approximately 0.3% of total global energy consumption.7–10 Accordingly, adsorption-based separation using porous materials has attracted increasing attention as a potential alternative to conventional distillation, offering opportunities for energy savings and reduced carbon emissions.11–13 However, the separation of C2H4 from ethane (C2H6) remains highly challenging due to their very similar physicochemical properties.14–17 Therefore, developing new adsorbent materials with pore structures precisely matched to the molecular dimensions of C2H4 and capable of meeting the requirements for efficient C2H4 purification has become a major focus of current research.

Over the past three decades, metal–organic frameworks (MOFs), as representative emerging porous adsorbents, have demonstrated great promise in the field of gas adsorption and separation.18–25 Owing to their high porosity, tunable pore structures, and structural diversity, MOFs are well suited to the demands of rational structural design for gas separations.26–33 Extensive studies have been conducted on MOFs for C2H4/C2H6 separation.34–37 Materials with a high density of open metal sites, such as the MOF-74 series and HKUST-1, achieve separation through strong interactions with C2H4 molecules, but typically exhibit co-adsorption of C2H6, leading to limited selectivity.11,38 To address this issue, strategies such as pore aperture reduction or introduction of functional sites have been widely explored to enhance C2H4/C2H6 discrimination. However, even when pore apertures are reduced or functional sites are introduced into the framework, most systems still fail to overcome the intrinsic limitation of synchronous variation in adsorption behavior, where modulation of pore environments simultaneously affects the adsorption strengths of both C2H4 and C2H6.39 For example, the porous aromatic framework PAF-1 can be converted to PAF-1-SO3H via sulfonation and further to PAF-1-SO3Ag via Ag+ exchange. Although the C2H4 uptake is enhanced compared with pristine PAF-1, a noticeable increase in C2H6 uptake at low pressure is also observed, thereby limiting improvements in overall selectivity.40 In addition, in the isostructural anion-pillared ultramicroporous MOF ZU-36 series, variations in metal centers lead to subtle differences in the framework structure and pore aperture, thereby influencing gas adsorption behavior. ZU-36-Ni exhibits a slightly smaller pore aperture than ZU-36-Co. Although the reduced pore size can modestly enhance size discrimination and slightly improve C2H4/C2H6 selectivity, the overall pore space contraction still results in a simultaneous decrease in both C2H4 and C2H6 uptake, leading to a typical trade-off between selectivity and capacity.41 Ideally, C2H4/C2H6 separation should be achieved by exploiting the subtle difference in molecular size, allowing selective adsorption of C2H4 while excluding C2H6. Because C2H4 (3.28 × 4.18 × 4.84 Å3) and C2H6 (3.81 × 4.08 × 4.82 Å3) differ only slightly in molecular dimensions, effective molecular sieving remains highly challenging (Table S1). To date, only a few MOFs have been reported to exhibit sieving behavior for C2H4/C2H6 separation, namely Co-gallate (M = Ni, Mg),42 UTSA-280,43 and BFFOUR-Cu-dpds.44 Despite recent progress, such sieving-type materials often suffer from low C2H4 uptake at low pressure and insufficient differentiation in adsorption response between C2H4 and C2H6, thereby constraining further improvements in separation performance.

Therefore, a key challenge lies in overcoming limitations of existing separation materials, including indiscriminate recognition in large-pore MOFs with poor selectivity, limited enhancement in selectivity arising from synchronous adsorption behavior while compromising C2H4 uptake, and insufficient low-pressure C2H4 capture in conventional sieving frameworks. In this context, we propose an asymmetric recognition strategy that introduces enriched polar functional sites and localized negative electrostatic potential within the pore environment and achieves C2H4/C2H6 separation through the cooperative regulation of the pore aperture and cavity microenvironment. This modulation further leads to inverse adsorption responses for the two gases, with size-sieving discrimination enabled by the narrowed pore aperture, enhanced C2H4 uptake and suppressed C2H6 adsorption, thereby enabling simultaneous improvement in both adsorption capacity and selectivity, while also strengthening host–guest interactions between C2H4 and the framework (Scheme 1). In this work, a one-dimensional channel MOF material, TYUT-25, was constructed to achieve cooperative regulation of the pore aperture and cavity microenvironment within the framework. The introduction of amino functional groups plays a dual role in this regulation, with the Lewis basic –NH2 groups located around the pore aperture inducing contraction of the effective pore window, thereby imposing a geometric constraint on the incoming molecules, while the polar amino groups modify the local electrostatic environment and provide favorable interaction sites within the cavity for C2H4 adsorption. TYUT-25 features a confined aperture-expanded cavity architecture. The contracted pore apertures act as “molecular gates”, effectively excluding C2H6 while allowing C2H4 diffusion into the channels, while the optimized cavity microenvironment enhances C2H4 binding through multiple cooperative interactions. In addition, the surrounding aromatic units are optimally arranged, and multiple C–H⋯π supramolecular interactions further anchor C2H4 molecules, thereby synergistically enhancing C2H4 adsorption and enrichment. Compared with Zn(BPA)(BDC), TYUT-25 shows a significant enhancement in C2H4 adsorption performance, increasing from 1.6 cm3 g−1 at 0.1 bar to 8.4 cm3 g−1 and further to 34.4 cm3 g−1 at 1 bar, indicating enhanced C2H4 uptake. In contrast, the C2H6 uptake decreases from 11.2 cm3 g−1 at 1 bar to 0.83 cm3 g−1, successfully achieving increased C2H4 adsorption and reduced C2H6 adsorption. Notably, the selectivity of TYUT-25 also increases from 2.5 for Zn(BPA)(BDC) to over 104.

Scheme 1. Schematic illustration of three recognition strategies toward C2H4/C2H6 separation, including indiscriminate recognition, synchronous recognition and asymmetric recognition.

Scheme 1

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2. Results and discussion

TYUT-25 and Zn(BPA)(BDC) were synthesized via a solvothermal method using zinc salts (Zn(NO3)2·6H2O), 1,2-bis(4-pyridyl)acetylene (bpa), and 2-aminoterephthalic acid (BDC-NH2) or terephthalic acid (BDC), respectively.45 Single-crystal X-ray diffraction analysis reveals that TYUT-25 crystallizes in the monoclinic P21/n space group (Fig. S1–S3 and Table S2). In this structure, TYUT-25 retains an identical coordination mode and structural configuration to the Zn(BPA)(BDC) framework. The Zn2+ centers adopt identical coordination environments, each forming a five-coordinate geometry defined by three oxygen atoms from carboxylate groups and two nitrogen atoms from different bpa ligands (Fig. S4). Two-dimensional layers constructed from BDC-NH2 linkers are connected by bpa ligands acting as pillar units along the vertical direction, giving rise to a three-dimensional pillared framework (Fig. S5–S7). Abundant amino sites and framework oxygen atoms are embedded within the pore interior, which can deliver localized negative electrostatic potential in TYUT-25 (Fig. S8–S11). This polarized electrostatic environment arises from the synergistic electron-donating effect of amino groups and electronegative oxygen atoms, leading to an electron-rich pore microenvironment. Such negative potential perfectly complements the positively charged hydrogen atoms of C2H4 molecules, thereby strengthening host–guest interactions and facilitating efficient C2H4 adsorption. TYUT-25 and Zn(BPA)(BDC) feature regular one-dimensional straight channels, displaying an architecture with small apertures and large cavities (Fig. S12 and S13). Zn(BPA)(BDC) exhibits a pore aperture of approximately 2.2 × 3.9 Å2 and a cavity size of 4.7 × 6.4 Å2. Upon amino-functionalization, the pore aperture of TYUT-25 is further reduced to approximately 2.0 × 3.6 Å2, while the cavity dimensions decrease slightly to 4.4 × 6.2 Å2. Upon activation at 215 °C, the TYUT-25 framework undergoes local structural adjustments, mainly involving changes in the angles of the pillar and interlayer ligands, while maintaining the overall coordination connectivity and topology (Fig. S14 and S15). The narrowed pore entrance enables discrimination between C2H4 (3.28 × 4.18 Å2) and C2H6 (3.81 × 4.08 Å2) based on their subtle differences in molecular cross-sections, making the smaller C2H4 molecule more favorable for entering the channel (Fig. 1a and b). Although the static pore aperture is relatively small, the pore entrance possesses an intrinsic dynamic adjustment capability that allows guest molecules to access the channel, a phenomenon that has also been reported in other related materials.46 Meanwhile, the moderately contracted cavity provides a favorable pore microenvironment, incorporating spatial confinement, functional sites, and electrostatic interactions, which collectively enhance the interaction with C2H4 molecules. The cooperative effect of aperture narrowing and cavity microenvironment thus establishes an advantageous structural setting for C2H4 recognition and separation, endowing TYUT-25 with promising molecular sieving capability toward C2H4/C2H6 mixtures.

Fig. 1. Pore structures, accessible Connolly surfaces, and electrostatic potential (ESP) distributions of (a) Zn(BPA)(BDC) and (b) TYUT-25. The cross-sectional dimensions of C2H4 and C2H6 are shown.

Fig. 1

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To evaluate the structural integrity and practical applicability of the materials, systematic characterization was carried out on TYUT-25 and Zn(BPA)(BDC). The experimental powder X-ray diffraction patterns (PXRD) are in good agreement with the simulated results, indicating high phase purity and crystallinity of the as-synthesized samples (Fig. 2a). The introduction of amino groups does not alter the overall crystal structure. The CO2 adsorption isotherms measured at 195 K exhibit typical Type I behavior, confirming the microporous nature of both materials. The BET (Brunauer–Emmett–Teller) surface area of Zn(BPA)(BDC) is 391 m2 g−1, while TYUT-25 exhibits a BET surface area of 364 m2 g−1, suggesting that the framework retains relatively high porosity after amino functionalization with only a moderate reduction. The pore sizes calculated based on the Horvath–Kawazoe model (HK) are 5.8 Å and 4.9 Å, respectively (Fig. 2b and c). To further evaluate the adsorption performance, CO2 adsorption was also measured at 273 K, demonstrating micropore adsorption behavior (Fig. S16 and S17). Thermogravimetric analysis (TGA) further reveals the thermal stability of the materials. Compared with Zn(BPA)(BDC), the first weight loss step of TYUT-25 begins at around 210 °C, which may be attributed to the reduced pore size caused by the introduction of –NH2 groups, making the removal of guest solvent molecules more difficult. In the range of 210 to 300 °C, solvent molecules confined in the pores are gradually released, and framework decomposition occurs only above 300 °C, indicating good thermal stability (Fig. 2d). The chemical stability of TYUT-25 was evaluated by immersing the sample in aqueous solutions with pH values ranging from 3 to 11. After treatment, TYUT-25 retains its crystallinity and regular block-like morphology without obvious damage, indicating that the framework maintains its structural integrity under the investigated conditions. Furthermore, the stability of fully activated TYUT-25 was evaluated under humid and acidic/basic conditions, where the sample retained its crystallinity and adsorption performance (Fig. 2e, f, S18 and S19). On this basis, the adsorption behaviors of C2H4 and C2H6 were systematically investigated.

Fig. 2. (a) PXRD patterns of the as-synthesized and simulated Zn(BPA)(BDC) and TYUT-25. (b and c) 195 K CO2 adsorption isotherms and pore size distribution curves calculated using the HK model for Zn(BPA)(BDC) and TYUT-25. (d) TGA curves of Zn(BPA)(BDC) and TYUT-25. (e) PXRD patterns of TYUT-25 after treatment under different pH conditions. (f) SEM images of TYUT-25 after treatment under different pH conditions.

Fig. 2

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The single-component adsorption isotherms of C2H4 and C2H6 were measured for Zn(BPA)(BDC) and TYUT-25 to examine the influence of pore environment modification on C2 hydrocarbon separation behavior. Zn(BPA)(BDC) exhibits similar adsorption capacities for C2H4 and C2H6 in the low-pressure region, with a C2H4 uptake of only ∼1.6 cm3 g−1 at 298 K and 0.1 bar, while C2H6 adsorption is negligible. At 298 K and 1 bar, the C2H4 uptake increases to 30 cm3 g−1 and the C2H6 uptake rises to 11.2 cm3 g−1. The differences in uptake across the measured pressure range suggest that Zn(BPA)(BDC) has limited selectivity between the two gases (Fig. 3a). In contrast, TYUT-25 exhibits a significantly enhanced C2H4 uptake of ∼8.4 cm3 g−1 at 298 K and 0.1 bar, 4.0 times higher than that of Zn(BPA)(BDC), while C2H6 adsorption remains negligible across the entire low-pressure region, indicating a pronounced adsorption divergence between the two gases. At 298 K and 1 bar, the C2H4 uptake further rises to 34.4 cm3 g−1, indicating that such structural regulation does not compromise C2H4 adsorption but instead enhances the affinity of the framework toward C2H4, leading to strengthened host–guest interactions and increased uptake (Fig. 3b). Meanwhile, C2H6 uptake decreases from 11.2 cm3 g−1 at 1 bar in Zn(BPA)(BDC) to 0.83 cm3 g−1 in TYUT-25, highlighting that, in contrast to the enhanced C2H4 adsorption, the more confined pore aperture effectively restricts C2H6 accommodation and leads to a clear inverse adsorption response.

Fig. 3. (a and b) C2H4 and C2H6 adsorption isotherms of Zn(BPA)(BDC) and TYUT-25 at 298 K. (c and d) Calculated C2H4/C2H6 IAST selectivity of TYUT-25 and Zn(BPA)(BDC), along with a comparison of selectivity and uptake ratios with representative materials. (e) C2H4 adsorption isotherms of TYUT-25 at 298 K and 313 K. (f) Qst of C2H4 on TYUT-25.

Fig. 3

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Notably, the adsorption performance of TYUT-25 is highly sensitive to the activation temperature. Distinct adsorption behaviors were observed under different activation conditions, with the optimal adsorption performance achieved after activation at 215 °C (Fig. S20 and S21). This behavior is associated with the activation-induced local structural adjustments in TYUT-25 (Fig. S14). In contrast, Zn(BPA)(BDC) exhibits largely unchanged adsorption properties over the same activation temperature range (Fig. S22 and S23). Overall, pore environment regulation thus substantially amplifies the adsorption difference between C2H4 and C2H6 and increases the low-pressure C2H4 uptake, thereby improving selectivity. TYUT-25 demonstrates clear potential for C2H4/C2H6 separation compared with Zn(BPA)(BDC). Ideal adsorbed solution theory (IAST) calculations indicate a C2H4/C2H6 selectivity >104, which remains extremely high over a wide pressure range (Fig. 3c, S24, and S25 and Tables S3 and S4). Benchmarking against representative C2H4/C2H6 separation materials from the literature shows that TYUT-25 simultaneously achieves high selectivity (>104) and a competitive uptake ratio (41.3), surpassing some standard references, such as NOTT-300 (48.7, 5.04),32 Co-gallate (52, 10.8),42 and BFFOUR-Cu-dpds (68.8, 14.9),44 placing it at the forefront of this class of adsorbents (Fig. 3d and Table S5). The adsorption enthalpy of C2H4 on TYUT-25 was evaluated from isotherms at different temperatures to probe interaction strength. The 1 bar C2H4 uptake decreases from 34.4 cm3 g−1 to 25.3 cm3 g−1 with increasing temperature (Fig. 3e). Using the Clausius–Clapeyron equation, the zero-loading adsorption enthalpy of C2H4 on TYUT-25 is 38.3 kJ mol−1 (Fig. 3f), indicating a strong affinity toward C2H4. This value exceeds those of several representative C2H4 adsorbents, including NOTT-300 (16 kJ mol−1),32 BFFOUR-Cu-dpds (34.4 kJ mol−1)44 and UTSA-280 (35.0 kJ mol−1),43 demonstrating the enhanced host–guest interactions between C2H4 molecules and the TYUT-25 framework (Fig. S26).

To gain molecular level insight into the observed differences in C2H4 adsorption, we combined Grand Canonical Monte Carlo (GCMC) simulations and Density Functional Theory (DFT) calculations to systematically analyze the adsorption density distribution and the preferred adsorption sites of C2H4 in Zn(BPA)(BDC) and activated TYUT-25 at 298 K and 1 bar. GCMC results show that in the pristine MOF, C2H4 molecules are dispersed throughout the pores with relatively low overall adsorption density, while after amino modification, C2H4 molecules tend to aggregate in specific regions of the pores, leading to a significant increase in local adsorption density, which indicates that the introduction of amino groups provides more favorable adsorption sites and enhances the interactions between the molecules and the framework (Fig. S27 and S28). To further elucidate the nature of these interactions, DFT calculations were performed to obtain the optimal adsorption configurations of C2H4 in both frameworks. In Zn(BPA)(BDC), C2H4 molecules adopt a parallel orientation within the pores and interact with the framework mainly through weak C–H⋯O and C–H⋯π interactions with relatively long distances (C–H⋯O: 3.55–3.90 Å; C–H⋯π: 2.78–3.84 Å) and only a single C–H⋯N interaction (2.98 Å) (Fig. 4a). In contrast, in TYUT-25, C2H4 molecules are stabilized within the pores through multiple dense interactions with the framework, resulting in stronger host–guest interactions. Specifically, the numbers of C–H⋯N, C–H⋯O, and C–H⋯π interactions increase, and the interaction distances decrease overall (C–H⋯N: 2.94–3.87 Å; C–H⋯O: 2.31–3.78 Å; C–H⋯π: 2.52–3.68 Å), reflecting a regulated cavity microenvironment with increased accessible binding sites for C2H4 within the framework. The binding energy of C2H4 in TYUT-25 is calculated to be 43.14 kJ mol−1 (Fig. 4b). These strengthened host–guest interactions consequently lead to a more confined local adsorption environment for C2H4 within TYUT-25. C2H4 molecules in TYUT-25 experience closer host–guest contact distances and enhanced spatial confinement within the pore environment (Fig. 4c and d).

Fig. 4. (a and b) DFT-calculated C2H4 adsorption sites in Zn(BPA)(BDC) and activated TYUT-25. (c and d) Preferential binding sites for C2H4 and their close contacts with the framework in Zn(BPA)(BDC) and activated TYUT-25. (e and f) Hirshfeld surfaces and 2D fingerprint plots of C2H4 in Zn(BPA)(BDC) and activated TYUT-25.

Fig. 4

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To gain deeper insights into host–guest interactions at the molecular level, the Hirshfeld surfaces and 2D fingerprint plots of C2H4 adsorbed in Zn(BPA)(BDC) and TYUT-25a were compared (Fig. 4e and f). In contrast to the predominantly blue surface of Zn(BPA)(BDC) that signifies weak interactions, the Hirshfeld surface of TYUT-25a displays distinct red regions, visually reflecting strong and specific intermolecular interactions. In the corresponding 2D fingerprint plots, the overall distribution of TYUT-25 shifts and clusters toward the lower-left shorter contact region (with di and de extending down to ∼1.2 Å), indicating a higher adsorption affinity between C2H4 and the framework. Detailed analysis of specific atomic contacts further elucidates the origin of the enhanced adsorption behavior. Compared with C2H4-loaded Zn(BPA)(BDC), TYUT-25 exhibits increased and sharpened distributions of H⋯C and H⋯H contacts toward shorter distances, while enhanced H⋯N contacts are also observed upon amino functionalization (Fig. S29 and S30). Charge density difference analysis further shows more pronounced local electronic changes around the adsorption region in TYUT-25 than in Zn(BPA)(BDC), indicating a distinct electronic environment at the C2H4 adsorption sites (Fig. S31). These findings confirm the effectiveness of the asymmetric recognition strategy in reconstructing the pore cavity microenvironment, thereby cooperatively strengthening multiple interactions between C2H4 and the framework.

Breakthrough experiments were conducted to evaluate the dynamic separation performance toward an equimolar C2H4/C2H6 mixture (50/50, v/v) at 298 K (Fig. S32). For Zn(BPA)(BDC), C2H4 and C2H6 broke through the column at nearly the same time, indicating negligible separation capability. Specifically, C2H6 eluted at approximately 8 min, while C2H4 broke through at approximately 15 min, resulting in a short separation window of only about 7 min (Fig. 5a). In contrast, TYUT-25 displayed pronounced separation behavior. C2H6 eluted rapidly, while C2H4 was retained much longer and broke through at around 22 min. This resulted in a clear separation window of about 21 min between the two gases, which is nearly three times larger than that of Zn(BPA)(BDC) (Fig. 5b). The C2H4 uptake before breakthrough was estimated to be 0.49 mmol g−1, with the lower uptake mainly attributed to the relatively slow diffusion of C2H4 through the narrow pore apertures. Integration of the entire breakthrough curve gave a total dynamic adsorption capacity of 1.08 mmol g−1, corresponding to 89.3% of the equilibrium uptake of 1.21 mmol g−1 obtained from the single-component adsorption isotherm under the same pressure of 0.5 bar (Fig. S33). To assess the stability of the material, cyclic breakthrough experiments were performed. For single-component C2H4, three consecutive runs produced nearly identical breakthrough curves, indicating stable adsorption behavior (Fig. 5c). Similarly, repeated breakthrough tests using the C2H4/C2H6 mixture showed highly reproducible profiles for both gases over three cycles (Fig. 5d), demonstrating excellent structural robustness and consistent separation performance. These results confirm that the regulated pore microenvironment in TYUT-25 enables efficient dynamic separation of the challenging C2H4/C2H6 mixture with good cycling stability.

Fig. 5. (a and b) Binary breakthrough curves of C2H4/C2H6 (50/50 v/v) for Zn(BPA)(BDC) and TYUT-25. (c) Single-component breakthrough curves of C2H4 for TYUT-25 in three consecutive cycles. (d) Recyclability test of binary C2H4/C2H6 (50/50 v/v) breakthrough separation for TYUT-25 over three consecutive cycles.

Fig. 5

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3. Conclusion

This work utilizes an asymmetric recognition strategy to achieve the cooperative regulation of pore aperture and cavity microenvironment, thereby inducing an inverse response in the adsorption capacities of C2H4 and C2H6. Compared with Zn(BPA)(BDC), the constructed TYUT-25 exhibits enhanced C2H4 adsorption while suppressing C2H6 uptake. At 0.1 bar, the C2H4 uptake significantly increases from 1.6 cm3 g−1 to 8.4 cm3 g−1 and further rises to 34.4 cm3 g−1 at 1 bar, originating from strengthened host–guest interactions. Meanwhile, the restricted pore aperture, governed by a size-sieving effect, reduces the C2H6 uptake from 11.2 cm3 g−1 to 0.83 cm3 g−1, resulting in a substantial increase in selectivity from 2.5 to >104. This result effectively circumvents the inherent limitation of synchronous adsorption behavior in conventional systems. The synergistic effect of pore aperture and cavity microenvironment regulation further establishes a platform for coupling molecular sieving with host–guest interaction modulation. This work not only demonstrates a high-performance adsorbent for C2H4/C2H6 separation but also provides a potential design strategy for achieving inverse adsorption responses in porous materials.

Author contributions

Y. D.: data curation, formal analysis, writing – original draft, and writing – review & editing. D. Y.: data curation. L. Y.: formal analysis. Y. W.: formal analysis. B. Y.: validation. Y. C.: conceptualization, formal analysis, validation, writing – review & editing, funding acquisition, and project administration. L. L.: data curation, formal analysis, validation, writing – review & editing, funding acquisition, and project administration. J. L.: formal analysis and conceptualization.

Conflicts of interest

There are no conflicts to declare.

Supplementary Material

SC-OLF-D6SC05421H-s001
SC-OLF-D6SC05421H-s002

Acknowledgments

The research work was supported by the National Natural Science Foundation of China (22422810, 22278287, and 22278288).

Data availability

CCDC 2339591 (TYUT-25) and 2581666 (TYUT-25-activated) contain the supplementary crystallographic data for this paper.47a,b

The data supporting this article have been included as part of the supplementary information (SI). Supplementary information: experimental synthesis and measurement details, adsorption test data, stability test results, crystallographic data, and theoretical computational details. See DOI: https://doi.org/10.1039/d6sc05421h.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Citations

  1. (a) CCDC 2339591: Experimental Crystal Structure Determination, 2026, 10.5517/ccdc.csd.cc2jjjp9 [DOI]
  2. (b) CCDC 2581666: Experimental Crystal Structure Determination, 2026, 10.5517/ccdc.csd.cc2snfkg [DOI]

Supplementary Materials

SC-OLF-D6SC05421H-s001
SC-OLF-D6SC05421H-s001.pdf (6.8MB, pdf)
SC-OLF-D6SC05421H-s002
SC-OLF-D6SC05421H-s002.cif (59.5KB, cif)

Data Availability Statement

CCDC 2339591 (TYUT-25) and 2581666 (TYUT-25-activated) contain the supplementary crystallographic data for this paper.47a,b

The data supporting this article have been included as part of the supplementary information (SI). Supplementary information: experimental synthesis and measurement details, adsorption test data, stability test results, crystallographic data, and theoretical computational details. See DOI: https://doi.org/10.1039/d6sc05421h.

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