Molecular Sieving of Propyne/Propylene by a Scalable Nanoporous Crystal with Confined Rotational Shutters.

Soft porous coordination polymers (PCPs) have the remarkable ability to recognize similar molecules as a result of their structural dynamics. However, their guest-induced gate-opening behaviors often lead to issues with selectivity and separation efficiency, as co-adsorption is nearly unavoidable. Herein, we report a strategy of a confined-rotational shutter, in which the rotation of pyridyl rings within the confined nanospace of a halogen-bonded coordination framework (NTU-88) creates a maximum aperture of 4.4 Å, which is very close to the molecular size of propyne (C3 H4 : 4.4 Å), but smaller than that of propylene (C3 H6 : 5.4 Å). This has been evidenced by crystallographic analyses and modelling calculations. The NTU-88o (open phase of activated NTU-88) demonstrates dedicated C3 H4 adsorption, and thereby leads to a sieving separation of C3 H4 /C3 H6 under ambient conditions. The integrated nature of high uptake ratio, considerable capacity, scalable synthesis, and good stability make NTU-88 a promising candidate for the feasible removal of C3 H4 from C3 H4 /C3 H6 mixtures. In principle, this strategy holds high potential for extension to soft families, making it a powerful tool for optimizing materials that can tackle challenging separations with no co-adsorption, while retaining the crucial aspect of high capacity.

Facile Solution-Refluxing Synthesis and Photocatalytic Dye Degradation of a Dynamic Covalent Organic Framework.

Covalent organic frameworks (COFs), as a novel crystalline porous adsorbent, have been attracting significant attention for their synthesis and application exploration due to the advantages of designability, stability, and functionalization. Herein, through increasing the concentration of the acid catalyst, a facile solution-refluxing synthesis method was developed for the preparation of a three-dimensional dynamic COF material, COF-300, with high yields (>90%) and high space−time yields (>28 kg m−3 day−1). This synthesis method not only permits gram-scale synthesis, but also yields products that well maintain porosity and unique guest-dependent dynamic behavior. Moreover, the catalytic activity of COF-300 as a metal-free photocatalyst was explored for the first time. Under 365 nm ultra-violet light irradiation, COF-300 can effectively catalyze the dye degradation (>99%) in wastewater with good recyclability. By adding magnetic Fe3O4 nanoparticles into the solution-refluxing synthesis of COF-300, Fe3O4/COF-300 nanocomposites can be obtained and used as magnetically recyclable photocatalysts, demonstrating the superiority of this facile synthesis procedure. Our study provides new insights for the preparation of COF materials and a constructive exploration for their water treatment application.

Association between SEMA3A signaling pathway genes and BMD/OP risk: An epidemiological and experimental study.

Objective: This study aimed to explore the associations of genetic variants in the semaphorin 3A (SEMA3A) signaling pathway genes, including SEMA3A, NRP1, PLXNA1, PLXNA2 and PLXNA3 with osteoporosis (OP) risk and bone mineral density (BMD) in a Chinese Han older adult population. Study design and method: A two-stage design was adopted. Total of 47.8kb regions in the 5 genes were sequenced using targeted next-generation sequencing (NGS) technology in the discovery stage, and the discovered OP-related single nucleotide polymorphisms (SNPs) were further genotyped using improved multiple linkage detection reaction technique in the validation stage. Methods of ALP/TRAP staining, real-time fluorescent quantitative PCR, and cell proliferation and apoptosis assays were performed with MC3T3-E1 and RAW 264.7 cell lines to clarify biological effects of observed functional variants in cell lines responsible for bone mass remodeling. Results: Total of 400 postmenopausal women (211 OP cases) were involved in the discovery stage, where 6 common and 4 rare genetic variants were found to be associated with OP risk. In the validation stage among another 859 participants (417 women, 270 OP cases), the PLXNA2 rs2274446 T allele was associated with reduced OP risk and increased femoral neck (FN) BMD compared to the C allele. Moreover, significant associations of NRP1 rs2070296 with FN BMD/OP risk and of NRP1 rs180868035 with lumbar spine and FN BMDs were also observed in the combination dataset analysis. Compared to the osteoblasts/osteoclasts transfected with the wild-type NRP1 rs180868035, those transfected with the mutant-type had reduced mRNA expression of osteoblastic genes (i.e., ALP, RUNX2, SP7 and OCN), while elevated mRNA expression of osteoclastic genes (i.e., TRAP, NFATc1 and CTSK). Furthermore, mutant NRP1 rs180868035 transfection inhibited osteoblast proliferation and osteoclast apoptosis, while promoted osteoclast proliferation and osteoblast apoptosis in corresponding cell lines. Conclusion: Genetic variants located in NRP1 and PLXNA2 genes were associated with OP risk and BMD. The NRP1 rs180868035 affects bone metabolism by influencing osteoblasts and osteoclasts differentiation, proliferation and apoptosis.

Association of volatile organic compounds co-exposure with bone health indicators and potential mediators.

Limited evidence was found in the associations of volatile organic compound (VOC) exposure with bone health indicators. This study aimed to explore the associations of individual and combined metabolites of VOCs (mVOCs) in urine, a representative of the internal exposure level of VOCs, with bone mineral density (BMD), osteoporosis (OP) and fracture, and potential mediators. Data of the National Health Examination and Nutrition Survey 2005-2006 and 2013-2014 was used. Multiple linear and logistic regression modeling were performed to analyze the associations of individual mVOC with bone health indicators. The least absolute shrinkage and selection operator (LASSO) regression was adopted to select mVOCs that were more relevant to bone health indicators for further weight quantile sum (WQS) analysis used for analyzing the associations between multiple VOC co-exposure and bone health indicators. Mediation analysis was used to identify potential mediators. Seventeen mVOC members with detection rate of >50% in urine of all 3478 participants aged ≥20 years (1829 females) were involved. Levels of most mVOCs were higher in women than men. Eight mVOCs were negatively associated with BMDs, and two and four mVOCs were positively associated with OP and fracture risks, respectively. WQS regression revealed decreased femoral neck BMD (ß = -0.010 g/cm2, 95% CI: -0.020, -0.0001) and total spine BMD (ß = -0.015 g/cm2, 95% CI: -0.028, -0.002) in response to increasing mVOC mixture levels. And alkaline phosphatase (ALP), body mass index (BMI), fasting insulin (FI) and high-density lipoprotein (HDL), were mediators in the associations with proportions of mediating effect ranging from 4.6% to 10.2%. Individual and combined VOC (co-)exposure were associated with reduced BMDs in American adults. ALP, BMI, FI and HDL were demonstrated to be mediators in the association of multiple VOC co-exposure with BMD.

An evaluation index system for regional mobile SARS-CoV-2 virus nucleic acid testing capacity in China: a modified Delphi consensus study.

BACKGROUND: Large-scale detection has great potential to bring benefits for containing the COVID-19 epidemic and supporting the government in reopening economic activities. Evaluating the true regional mobile severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus nucleic acid testing capacity is essential to improve the overall fighting performance against this epidemic and maintain economic development. However, such a tool is not available in this issue. We aimed to establish an evaluation index system for assessing the regional mobile SARS-CoV-2 virus nucleic acid testing capacity and provide suggestions for improving the capacity level. METHODS: The initial version of the evaluation index system was identified based on massive literature and expert interviews. The Delphi method questionnaire was designed and 30 experts were consulted in two rounds of questionnaire to select and revise indexes at all three levels. The Analytic Hierarchy Process method was used to calculate the weight of indexes at all three levels. RESULTS: The evaluation index system for assessing the regional mobile SARS-CoV-2 virus nucleic acid testing capacity, including 5 first-level indexes, 17 second-level indexes, and 90 third-level indexes. The response rates of questionnaires delivered in the two rounds of consultation were 100 and 96.7%. Furthermore, the authority coefficient of 30 experts was 0.71. Kendall's coordination coefficient differences were statistically significant (P < 0.001). The weighted values of capacity indexes were established at all levels according to the consistency test, demonstrating that 'Personnel team construction' (0.2046) came first amongst the five first-level indexes, followed by 'Laboratory performance building and maintenance' (0.2023), 'Emergency response guarantee' (0.1989), 'Information management system for nucleic acid testing resources' (0.1982) and 'Regional mobile nucleic acid testing emergency response system construction' (0.1959). CONCLUSION: The evaluation system for assessing the regional mobile SARS-CoV-2 virus nucleic acid testing capacity puts forward a specific, objective, and quantifiable evaluation criterion. The evaluation system can act as a tool for diversified subjects to find the weak links and loopholes. It also provides a measurable basis for authorities to improve nucleic acid testing capabilities.

Ligand Tailoring Strategy of a Metal-Organic Framework for Optimizing Methane Storage Working Capacities.

Methane, as the main component of natural gas, shale gas, and marsh gas, is regarded as an ideal clean energy to replace traditional fossil fuels and reduce carbon emissions. Porous materials with superior methane storage capacities are the key to the wide application of adsorbed natural gas technology in vehicle transportation. In this work, we applied a ligand tailoring strategy to a metal-organic framework (NOTT-101) to fine-tune its pore geometry, which was well characterized by gas and dye sorption measurements. High-pressure methane sorption isotherms revealed that the methane storage performance of the modified NOTT-101 can be effectively improved by decreasing the unusable uptake at 5 bar and increasing the total uptake under high pressures, achieving a substantially high volumetric methane storage working capacity of 190 cm3 (STP) cm-3 at 298 K and 5-80 bar.

Association Between Water Intake and Mortality Risk-Evidence From a National Prospective Study.

Background: Few studies have explored the association between water intake and mortality risk, and the findings were inconsistent. Objective: This study aimed to explore the water intake-mortality association, utilizing the data from the National Health and Nutrition Examination Survey (NHANES) and the 2015 public-linked mortality files released by the National Center for Health Statistics. Methods: We used the diet- and mortality-linked data of a total of 35,463 adults (17,234 men) aged ≥20 years in the NHANESs 1999-2014 to perform a prospective study. The multivariate-adjusted Cox proportional hazards model was used to explore the associations of the amount of water intake (expressed by total water, plain water, beverage, and food water) and water intake proportion (expressed by the percentage of each kind of water) with mortality risks due to all causes, malignant neoplasms/cancer, and heart disease. The restricted cubic spline plots were adopted to clarify the dose-response relationships among them. Results: With a median of 88 months (interquartile range: 49-136 months) follow-up, a total of 4,915 all-cause deaths occurred, including 1,073 and 861 deaths from malignant neoplasms/cancer and heart disease, respectively. The amount of water intake in either type was negatively associated with all-cause mortality risk. Additionally, the negative linear dose-response relationships of water intake and all-cause mortality risk were found for all types of water except for food water, which followed a non-linear pattern. Similarly, compared to the lowest quartile (beverage water intake: <676 g/day; food water intake: <532 g/day), beverage and food water intakes in the range of 1,033-1,524 and 1,612-3,802 g/day were associated with decreased malignant neoplasms/cancer mortality risk. A U-shaped dose-response relationship was found for beverage water intake and malignant neoplasms/cancer mortality risk and a negative linear dose-response relationship was found for food water intake and malignant neoplasms/cancer mortality risk. Coffee and/or tea consumption was/were negatively associated with mortality risks due to all causes and malignant neoplasms/cancer. No significant associations of water intake proportion and mortality risks were found. Conclusion: Our findings demonstrated that higher water intake is associated with lower mortality risks among the United States population.

Multiple vitamin co-exposure and mortality risk: A prospective study.

BACKGROUND & AIMS: Existing epidemiological studies explored the associations of circulating vitamins and mortality focusing on individual vitamin effects, and controversial findings were obtained. The joint effects of multiple vitamin co-exposure are worth studying. The study aimed to elucidate the associations of circulating vitamins and the joint effects of these vitamins' co-exposure with all-cause and cause-specific mortality risks. METHODS: We prospectively evaluated the associations of the concentrations of six kinds of vitamins (A, D, E, C, B12 and B9) in serum with risks for all-cause and cause-specific mortalities among U.S. adults. Mortality status and cause of death were determined by NHANES-linked public available files dated up to 31 December 2015. An unsupervised K-means clustering method was used to cluster the participants into several vitamin co-exposure patterns. The Cox proportional hazards model was used for statistical analysis. RESULTS: A total of 1404 deaths occurred during a median of 10.9 years follow-up among 8295 participants. In multivariable adjustment, increasing levels of vitamin D were associated with reduced all-cause and cause-specific mortality risks. A J-shaped nonlinear exposure-response relationship was observed between all studied vitamins (except for vitamin D) and all-cause mortality risk. Four co-exposure patterns were generated based on the studied vitamins, as follows: low-level exposure (cluster 1), vitamin A/D exposure (cluster 2), water-soluble vitamin exposure (cluster 3) and high-level exposure (cluster 4). Compared with those in cluster 1, participants in cluster 2 had lower all-cause and cancer mortality risks, with hazard ratios (95% confidence intervals [CIs]) of 0.67 (0.53, 0.85) and 0.45 (0.29, 0.71), respectively. CONCLUSIONS: The findings in this study indicated that high circulating vitamin D levels were associated with reduced mortality risk among U.S. adults. Vitamin co-exposure at moderate levels appropriately contributed to low all-cause and cancer mortality risks. Our findings provided a novel perspective for exploring the joint health effects of multivitamin co-exposure. Future investigations are needed to further unravel the underlying mechanisms of possible vitamin interactions.

Integrative Analysis of LGR5/6 Gene Variants, Gut Microbiota Composition and Osteoporosis Risk in Elderly Population.

Objective: This study aimed to explore the relationships between the common variants of R-spondin/Wnt signaling genes, gut microbiota composition, and osteoporosis (OP) risk in elderly Chinese Han population. Design: Dual-energy X-ray absorptiometry was used to obtain the OP-associated measurements at multiple skeleton sites among all 1,168 participants. Genotyping data was obtained by using the next-generation sequencing in the discovery stage (n = 400, 228 OP patients) and SNPscan technology in the replication stage (n = 768, 356 OP patients). Bioinformatic analysis was performed to provide more evidence for the genotype-OP associations. The 16S ribosomal RNA gene high-throughput sequencing technology was adopted to explore OP-associated gut microbiota variations. Results: The genetic variants of rs10920362 in the LGR6 gene (P-FDR = 1.19 × 10-6) and rs11178860 in the LGR5 gene (P-FDR = 1.51 × 10-4) were found to associate with OP risk significantly. Several microbial taxa were associated with the BMDs and T-scores at multiple skeleton sites. The associations between rs10920362 and BMD-associated microbiota maintained significance after adjusting confounders. The rs10920362 CT/TT genotype associated with a decreased relative abundance of Actinobacteria (ß = -1.32, P < 0.001), Bifidobacteriaceae (ß = -1.70, P < 0.001), and Bifidobacterium (ß = -1.70, P < 0.001) compared to the CC genotype. Conclusion: Our findings suggested that the variants loci of LGR6 may be associate with OP pathogenesis via gut microbiota modifications. The relationship between host genetics and gut microbiome provides new perspectives about OP prevention and treatment.

Associations of multiple metals with bone mineral density: A population-based study in US adults.

Epidemiologic studies focus on combined effects of multiple metals on bone mineral density (BMD) are scarce. Therefore, this study was conducted to examine associations of multiple metals exposure with BMD. Data of adults aged ≥20 years (n = 2545) from the US National Health and Nutrition Examination Survey (NHANES, 2011-2016) were collected and analyzed. Concentrations of metals were measured in blood (cadmium [Cd], lead [Pb], mercury [Hg], and manganese [Mn]) and serum (copper [Cu], selenium [Se], and zinc [Zn]) using inductively coupled plasma mass spectrometry and inductively coupled plasma dynamic reaction cell mass spectrometry, respectively. The weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models were performed to determine the joint effects of multiple metals exposure on lumbar and total BMD. The linear regression analyses showed Pb was negatively associated with BMDs. The WQS regression analyses revealed that the WQS index was inversely related to lumbar (ß = -0.022, 95% CI: -0.036, -0.008) and total BMD (ß = -0.015, 95% CI: -0.024, -0.006), and Se, Mn, and Pb were the main contributors for the combined effects. Additionally, nonlinear dose-response relationships between Pb, Mn, and Se and BMD, as well as a synergistic interaction of Pb and Mn, were found in the BKMR analyses. Our findings suggested co-exposure to Cd, Pb, Hg, Mn, Cu, Se, and Zn (above their 50th percentiles) was associated with reduced BMD, and Pb, Mn, and Se were the main contributors driving the overall effects.

A Porous Coordination Polymer Showing Guest-Amplified Positive and Negative Thermal Expansion.

A solvothermal reaction of Zn(NO3)2 and 4-(1H-pyrazol-4-yl)benzoic acid (H2pba) with toluene (Tol) as the template yielded a porous coordination polymer, [Zn(pba)]·0.5Tol, possessing a three-dimensional (3D) fence-like coordination framework based on inclined two-dimensional (2D) fence-like coordination layers. By virtue of the classic deformation mode of the 2D/3D fence structures, the guest-free structure exhibits very large positive thermal expansion of 347 MK-1 and moderate negative thermal expansion of -63/-83 MK-1, which are remarkably enhanced to new records of 689 and -171/-249 MK-1, respectively, by inclusion of Tol.

Two Isostructural Flexible Porous Coordination Polymers Showing Contrasting Single-Component and Mixture Adsorption Properties for Propylene/Propane.

Solvothermal reactions of 3-(3-methylpyridin-4-yl)benzoic acid (Hmpba) with Mn(NO3)2 or Co(NO3)2 yielded isostructural porous coordination polymers, [Mn(mpba)2]·guest (MCF-56, 1·g) and [Co(mpba)2]·guest (MCF-57, 2·g), respectively. X-ray diffraction revealed that 1·g and 2·g possess similar one-dimensional ultramicroporous channels, and guest-free [Mn(mpba)2] (1') and [Co(mpba)2] (2') possess significantly and slightly contracted channels, respectively. Single-component C3H6/C3H8 adsorption isotherms and computational simulations showed the typical nonporous-to-porous structural transformations for 1', in which C3H6 exhibits a significantly lower threshold pressure, and the typical small-pore-to-large-pore structural transformations for 2', in which C3H6 exhibits a slightly lower threshold pressure. Mixture column breakthrough experiments showed that the C3H6/C3H8 separation performances of 2' are obviously better than those of 1', because the latter cannot adsorb C3H6 below the threshold pressure for pore opening, and the pore opened by C3H6 can adsorb C3H8.

Guest-Dependent Dynamics in a 3D Covalent Organic Framework.

Guest-dependent dynamics having both crystal contraction and expansion upon inclusion of various guests is uncovered in a 3D covalent organic framework (COF) prepared with a facile and scalable method. A molecular-level understanding of how the framework adjusts the node geometry and molecular configuration to perform significant contraction and large amplitude expansion are resolved through synchrotron in-house powder X-ray diffraction (PXRD) and Rietveld refinements. We found that the COF adopts a contracted phase at ambient conditions upon capturing moisture and is also adaptive upon inclusion of organic solvents, which is highlighted by a large crystal expansion (as large as 50% crystallographic volume increment and a 3-fold channel size enlargement). With this new knowledge of the structural adaptability, the diverse responses and coherent switchability are thereby presented to pave the way to rational design and deliberate control of dynamic COFs.

Flexibility of Metal-Organic Framework Tunable by Crystal Size at the Micrometer to Submillimeter Scale for Efficient Xylene Isomer Separation.

Understanding, controlling, and utilizing the flexibility of adsorbents are of great importance and difficulty. Analogous with conventional solid materials, downsizing to the nanoscale is emerging as a possible strategy for controlling the flexibility of porous coordination polymers (or metal-organic frameworks). We report a unique flexibility controllable by crystal size at the micrometer to submillimeter scale. Template removal transforms [Cu2(pypz)2]·0.5p-xylene (MAF-36, Hpypz = 4-(1H-pyrazol-4-yl)pyridine) with one-dimensional channels to α-[Cu2(pypz)2] with discrete small cavities, and further heating gives a nonporous isomer ß-[Cu2(pypz)2]. Both isomers can adsorb p-xylene to give [Cu2(pypz)2]·0.5p-xylene, meaning the coexistence of guest-driven flexibility and shape-memory behavior. The phase transition temperature from α-[Cu2(pypz)2] to ß-[Cu2(pypz)2] decreased from ~270°C to ~150°C by increasing the crystal size from the micrometer to the submillimeter scale, ca. 2-3 orders larger than those of other size-dependent behaviors. Single-crystal X-ray diffraction showed coordination bond reconstitution and chirality inversion mechanisms for the phase transition, which provides a sufficiently high energy barrier to stabilize the metastable phase without the need of downsizing to the nanoscale. By virtue of the crystalline molecular imprinting and gate-opening effects, α-[Cu2(pypz)2] and ß-[Cu2(pypz)2] show unprecedentedly high p-xylene selectivities of 16 and 51, respectively, as well as ultrafast adsorption kinetics (<2 minutes), for xylene isomers.

Molecular sieving of ethylene from ethane using a rigid metal-organic framework.

There are great challenges in developing efficient adsorbents to replace the currently used and energy-intensive cryogenic distillation processes for olefin/paraffin separation, owing to the similar physical properties of the two molecules. Here we report an ultramicroporous metal-organic framework [Ca(C4O4)(H2O)], synthesized from calcium nitrate and squaric acid, that possesses rigid one-dimensional channels. These apertures are of a similar size to ethylene molecules, but owing to the size, shape and rigidity of the pores, act as molecular sieves to prevent the transport of ethane. The efficiency of this molecular sieve for the separation of ethylene/ethane mixtures is validated by breakthrough experiments with high ethylene productivity under ambient conditions. This material can be easily synthesized at the kilogram scale using an environmentally friendly method and is water-stable, which is important for potential industrial implementation. The strategy of using highly rigid metal-organic frameworks with well defined and rigid pores could also be extended to other porous materials for chemical separation processes.

Organic-Inorganic Layered and Hollow Tin Bromide Perovskite with Tunable Broadband Emission.

Recently, layered perovskites attracted great attention for its excellent stability and light-emitting property. However, most of them rely on the toxic element lead and their emission quantum yields are generally low. Here, a unique hollow two-dimensional perovskite was developed in which the organic hexamethylene diamines (C6H18N22+) strongly coupled with distorted tin bromide anions (SnBr64-). This toxic-free low-dimensional tin perovskite exhibits a broadband emission in the visible region with a high luminescence quantum yield of 86%. First-principles calculation indicate the broadband emission is associated with the recombination of self-trapped excitons. And the emission is related to the geometry of tin bromide anions. An ultraviolet light-pumped white light emitting diode with excellent color-rendering index of 94 was fabricated using it together with a commercially available blue phosphor.

Controlling Thermal Expansion Behaviors of Fence-Like Metal-Organic Frameworks by Varying/Mixing Metal Ions.

Solvothermal reactions of 3-(4-pyridyl)-benzoic acid (Hpba) with a series of transition metal ions yielded isostructral metal-organic frameworks [M(pba)2]·2DMA (MCF-52; M = Ni2+, Co2+, Zn2+, Cd2+, or mixed Zn2+/Cd2+; DMA = N,N-dimethylacetamide) possessing two-dimensional fence-like coordination networks based on mononuclear 4-connected metal nodes and 2-connected organic ligands. Variable-temperature single-crystal X-ray diffraction studies of these materials revealed huge positive and negative thermal expansions with |α| > 150 × 10-6 K-1, in which the larger metal ions give the larger thermal expansion coefficients, because the increased space not only enhance the ligand vibrational motion and hinged-fence effect, but also allow larger changes of steric hindrance between the layers. In addition, the solid-solution crystal with mixed metal ions further validates the abundant thermal expansion mechanisms of these metal-organic layers.

Mesoporous Metal-Organic Frameworks with Exceptionally High Working Capacities for Adsorption Heat Transformation.

Pore size is one of the most important parameters of adsorbents, and mesoporous materials have received intense attention for large guests. Here, a series of mesoporous coordination polymers underlying a new framework prototype for fast expansion of pore size is reported and the profound effect of pore size on adsorption heat transformation is demonstrated. Three isostructural honeycomb-like frameworks are designed and synthesized by combining ditopic linear metal oxalate chains and triangular tris-pyridine ligands. Changing the ligand bridging length from 5.5 to 8.6 and 9.9 Å gives rise to effective pore diameter from 20 to 33 and 37 Å, surface area from 2096 to 2630 and 2749 m2 g-1 , and pore volume from 1.19 to 1.93 and 2.36 cm3 g-1 , respectively. By virtue of the unique and tunable isotherm shape of mesopores, exceptionally large working capacity up to 1.19 g g-1 or 0.38 g cm-3 for adsorption heat transformation can be achieved using R-134a (1,1,1,2-tetrafluroethane) as a working fluid.

Hyperfine adjustment of flexible pore-surface pockets enables smart recognition of gas size and quadrupole moment.

The pore size and framework flexibility of hosts are of vital importance for molecular recognition and related applications, but accurate control of these parameters is very challenging. We use the slight difference of metal ion size to achieve continuous hundredth-nanometer pore-size adjustments and drastic flexibility modulations in an ultramicroporous metal-organic framework, giving controllable N2 adsorption isotherm steps, unprecedented/reversed loading-dependence of H2 adsorption enthalpy, quadrupole-moment sieving of C2H2/CO2, and an exceptionally high working capacity for C2H2 storage under practical conditions (98 times that of an empty cylinder). In situ single-crystal X-ray diffraction measurements and multilevel computational simulations revealed the importance of pore-surface pockets, which utilize their size and electrostatic potential to smartly recognize the molecular sizes and quadruple moments of gas molecules to control their accessibility to the strongest adsorption sites.

Engineering of Pore Geometry for Ultrahigh Capacity Methane Storage in Mesoporous Metal-Organic Frameworks.

Mesoporous Zn4O(-COO)6-based metal-organic frameworks (MOFs), including UMCM-1, MOF-205, MUF-7a, and the newly synthesized MOFs, termed ST-1, ST-2, ST-3, and ST-4 (ST = ShanghaiTech University), have been systematically investigated for ultrahigh capacity methane storage. Exceptionally, ST-2 was found to have the highest deliverable capacity of 289 cm3STP/cm3 (567 mg/g) at 298 K and 5-200 bar, which surpasses all previously reported records held by porous materials. We illustrate that the fine-tuned mesoporosity is critical in further improving the deliverable capacities at ultrahigh pressure.