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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 (C3H4: 4.4 Å), but smaller than that of propylene (C3H6: 5.4 Å). This has been evidenced by crystallographic analyses and modelling calculations. The NTU‐88o (open phase of activated NTU‐88) demonstrates dedicated C3H4 adsorption, and thereby leads to a sieving separation of C3H4/C3H6 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 C3H4 from C3H4/C3H6 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. [ABSTRACT FROM AUTHOR]

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 (C3H4: 4.4 Å), but smaller than that of propylene (C3H6: 5.4 Å). This has been evidenced by crystallographic analyses and modelling calculations. The NTU‐88o (open phase of activated NTU‐88) demonstrates dedicated C3H4 adsorption, and thereby leads to a sieving separation of C3H4/C3H6 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 C3H4 from C3H4/C3H6 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. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Magnifying the controllable directional motions of molecular machines to the macroscopic levels is a significant topic for chemists. Flexible metal–organic frameworks with long‐range order and responsive structural transformation under external stimuli may be an appropriate platform for achieving the target. By taking advantage of the single‐crystal to single‐crystal manner of soft porous crystals, we utilize single‐crystal X‐ray diffraction to directly observe the dynamic structural inversion of a new three‐fold interpenetrated pillared‐layer metal‐organic framework [Co(edba)(bpy)] (MCF‐83, H2edba = 4,4'‐(ethyne‐1,2‐diyl)dibenzoic acid, bpy = 4,4'‐bipyridine). More interestingly, the dynamic inversions of the pillars and layers are selectively guest‐controllable and independent, allowing precise control of the directional shape changes, which is the key of constructing intelligent materials to accomplish a complex task. The mechanism is further studied by combining the X‐ray diffraction analyses, sorption measurements and molecular simulations. [ABSTRACT FROM AUTHOR]

Framework flexibility is one of the most important characteristics of metal–organic frameworks (MOFs), which is not only interesting, but also useful for a variety of applications. Designing, tailoring or controlling framework flexibility of MOFs is much more difficult than for static structural features such as the framework topology and pore size/shape. Nevertheless, with in-depth understanding of the relationship between framework flexibility and the host framework structure, guest loading and other aspects such as the crystal size/morphology and external physical environment, some strategies have been developed for controlling the flexibility of MOFs and the corresponding properties, which are summarized and discussed in this review. [ABSTRACT FROM AUTHOR]

Reactions of a new bent dipyridyl-type ligand, 3,6-di(pyridin-4-yl)-9H-carbazole (dpc), with different Zn(ii) salts yielded four coordination polymers, namely [ZnCl2(dpc)] (1), [Zn4Cl8(dpc)4]·1.44H2O (2), [ZnF(dpc)2(H2O)]PF6·2H2O·2DMF (3) (DMF = N,N-dimethylformamide), and [Zn(dpc)2(SiF6)]·guest (4). By virtue of the bent coordination geometries of both the tetrahedral Zn(ii) ion and the dipyridyl ligand, as well as the termination effect of the Cl− counter-anion/ligand, 1 is a single-stranded helical chain. 2 is a supramolecular isomer of 1 containing the same bent ZnCl2(dpc) secondary building unit, but four of such units interconnect to form a molecular Möbius ring. More interestingly, the molecular Möbius rings in 2 mechanically interlock with their neighbours to form a curb chain. With weakly coordinating PF6− as a counter-anion, 3 is a cationic loop chain consisting of vertex-sharing rhombus molecular rings built from two metal ions and two organic ligands. 4 contains vertex-sharing loop chains similar to those in 3, but they are connected by SiF62− to form a neutral layered network possessing intralayer channels for gas adsorption. [ABSTRACT FROM AUTHOR]

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 (β = −0.010 g/cm2, 95% CI: −0.020, −0.0001) and total spine BMD (β = −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. [Display omitted] • Individual and multiple VOCs co-exposure were associated with reduced BMD. • BMI, HDL, FI, and ALP mediated the association of VOCs co-exposure with BMD. • LASSO regression was used to select representative VOC and avoid collinearity. • WQS regression was used to explore the VOCs co-exposure and BMD association. [ABSTRACT FROM AUTHOR]

Through a modified solvothermal reaction using benzoic acid as an additive, the fcu-type framework [Zr6O4(OH)4(edba)6] (H2edba=4,4′-(ethyne-1,2-diyl)dibenzoic acid), an expanded version of UiO-66, is synthesized as high-quality single crystals, which can retain their single-crystallinity after solvent exchange and degas treatments. In situ variable-temperature single-crystal X-ray diffraction measurements show that the guest-free framework exhibits a remarkably large isotropic negative thermal expansion ( α=−11.0×10−6 K−1) as a result of the transverse vibrational bending of the long organic ligand. By virtue of the relatively large π-conjugation system of the organic ligand, [Zr6O4(OH)4(edba)6] also exhibits bright blue luminescence, which can be quenched efficiently by gaseous O2 ( Ksv=2.4 bar−1). [ABSTRACT FROM AUTHOR]

Three new coordination polymers based on 4,4′-(ethyne-1,2-diyl)dibenzoic acid (H2edba) and 2,2′-bipyridine (bpy) ligands, namely, [Zn(edba)(bpy)]·xGuest (1), [Cu(edba)(bpy)]·xGuest (2), and [Co3(edba)3(bpy)2]·3DMF·H2O (3) (DMF = N,N-dimethylformamide), were synthesized under the same solvothermal conditions except for the use of different metal ions. Single-crystal X-ray analysis indicates that with the different coordination habits of Zn2+, Cu2+, and Co2+ ions, the resulting compounds feature coordination structures with different dimensionalities, namely, a 1D zigzag chain based on single-ion nodes in 1, a 2D sql layer based on dinuclear 4-connected nodes in 2, and a 3D sxb framework based on trinuclear 6-connected nodes in 3. In addition, after the removal of guest molecules, the 2D framework of 2 and the 3D framework of 3 are stable enough for CO2 sorption with Langmuir surface areas of 440 cm2 g−1 and 542 cm3 g−1, respectively. The present study serves as an example, in which the metal ion acts as the sole reaction variable, demonstrating the significance of the metal ion in the structural diversity of coordination polymers. [ABSTRACT FROM AUTHOR]

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 cm³ STP/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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

An in-depth synthetic study for potential new supramolecular isomers of silver(i) 3,5-dialkyl-1,2,4-triazolates was carried out through liquid diffusion and rapid solution mixing of [Ag(NH3)2]OH and the related triazoles. Apart from the literature reported close-packing complexes of [Ag(dmtz)] (1a, Hdmtz = 3,5-dimethyl-1,2,4-triazole), [Ag(detz)] (2a, Hdetz = 3,5-diethyl-1,2,4-triazole), [Ag(dptz)] (3a, Hdptz = 3,5-dipropyl-1,2,4-triazole) and [Ag(diptz)] (4a, Hdiptz = 3,5-diisopropyl-1,2,4-triazole), four guest-containing isomers [Ag5(detz)5]·C6H6 (2b), [Ag4(dptz)4]·0.5C6H6 (3b), [Ag(diptz)]·0.5H2O (4b) and [Ag(diptz)]·C6H6 (4c) were discovered. Single-crystal X-ray diffraction studies revealed that 2b, 3b and 4b are complicated coordination networks with small discrete cavities, while 4c possesses an nbo-a framework topology with large discrete cavities embedding a unique supramolecular hexamer of benzene guest molecules with an orthogonal arrangement. Single-crystal and powder X-ray diffraction as well as thermogravimetry studies showed that 2b and 3b can undergo reversible temperature- and guest-induced single-crystal-to-single-crystal structural transformations, respectively, in which the conformation changes of the flexible alkyl groups play important roles. On the other hand, single crystals of 4c can transform into single crystals of another new isomer [Ag8(diptz)8]·C6H6·CH3OH (4d) with a completely different network connectivity, by immersing in methanol. [ABSTRACT FROM AUTHOR]

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 (β = −0.022, 95% CI: −0.036, −0.008) and total BMD (β = −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. [Display omitted] • Associations of multiple metals with BMD were examined in US adults aged ≥20 years. • WQS and BKMR models were applied to estimate the joint effects of multiple metals exposure. • Significant over-all effects of Cd, Pb, Hg, Mn, Cu, Se, and Zn were found in relation to BMD. • Mn, Pb, and Se are the main contributors to the combined effects on BMD. • Synergistic interaction exist between Mn and Pb on BMD. [ABSTRACT FROM AUTHOR]

[Display omitted] • Near defect-free and defect-rich UiO-66-type MOFs were successfully prepared. • Affecting mechanism of defects on CO 2 capture performance was elucidated. • Importance of thermal treatment for CO 2 capture performance was illustrated. • Necessity of identifying local fine structure for CO 2 capture evaluation was noted. Carbon capture and storage (CCS) technology is currently an essential response to the global warming problem caused by excessive CO 2 emissions. Efficient and reproducible adsorbents for flue gas treatment play an important role in CCS technology, and metal–organic frameworks (MOFs) are considered to be ideal candidates by virtue of their designable CO 2 sorption sites. However, carbon capture performance evaluation and reproducibility of MOFs still hinder their application promotion in industrial production. In this work, an extended UiO-66-type MOF based on 1,4-naphthalenedicarboxylate, was successfully synthesized in both a near defect-free form (UiO-66N) and a defect-rich form (DUiO-66N), for exploring the influence of crystalline defects and thermal treatments on carbon capture performance. Although powder X-ray diffraction showed that UiO-66N and DUiO-66N possessed the same crystalline phase, transmission electron microscopy, thermalgravimetric analyse and gas/dye sorption confirmed the presence of crystalline defects and the variation of porosity in DUiO-66N. CO 2 sorption isotherms and flue gas breakthrough experiments revealed the defect-induced improved carbon capture performance, which was also supported by density functional theory. Meanwhile, the metastability of defects required low thermal treatment temperatures for activation and regeneration thus maintaining the superior carbon capture performance. These findings suggested that in reproducing and evaluating the carbon capture performance of MOFs, it cannot rely only on the global crystalline phase judgment, but needs to identify the local fine structure as well as optimize activation and regeneration conditions. [ABSTRACT FROM AUTHOR]

A rhombic porous coordination polymer was synthesized as two conformational isomers with acute and obtuse interior angles, which can reversibly and irreversibly transform into a new conformation, undergoing not only single-side but also double-side swing. [ABSTRACT FROM AUTHOR]

Porous materials bearing free aliphatic amine groups are powerful adsorbents for carbon dioxide but generally have to be synthesized by complicated, multi-step post-synthetic modification methods due to the high activity of these functional groups. We report a crystal-engineering strategy for such metal–organic frameworks. Reactions of Zn(ii) ion with diversified coordination modes and bis(4-carboxy-benzyl)amine (H2bcba) with a secondary aliphatic amine bridge at different temperatures yielded a pair of isomeric frameworks with very similar framework structures but distinctly different local structures, namely α-[Zn(bcba)] (MCF-51 or α-Zn) with all amino groups coordinated and β-[Zn(bcba)] (MCF-52 or β-Zn) with uncoordinated amino groups. Single-component gas adsorption and CO2/CH4 mixture breakthrough experiments at ambient conditions showed that, the CO2 adsorption ability and CH4 purification performances of β-Zn, in terms of CO2 adsorption enthalpy (42 kJ mol−1), CO2/CH4 selectivity (32) and CH4 purity/productivity (1.49 mmol g−1 at 99.999%+), are much higher than those of α-Zn (CO2 adsorption enthalpy of 17 kJ mol−1, CO2/CH4 selectivity of 2.9 and CH4 purity/productivity of 0.088 mmol g−1 at 99%+). [ABSTRACT FROM AUTHOR]

A new coordination compound, [Cu(sphen)] (Hsphen = 2-sulfydryl-1,10-phenanthroline), as an analog of [Cu(ophen)] (Hophen = 1H-[1,10]phenanthrolin-2-one), is synthesized and characterized by single-crystal X-ray diffraction. While [Cu(ophen)] is a planar discrete complex showing strongπ–πstacking, [Cu(sphen)] is further connected by Cu–S bonds to form a one-dimensional coordination polymer. The bulk electrical conductivity of [Cu(sphen)] (5.0 × 10−3 S·cm−1) is ~3 orders of magnitude higher than that of [Cu(ophen)] (3.9 × 10−6 S·cm−1). [ABSTRACT FROM AUTHOR]

By changing the ligand substituent groups near the open metal sites from hydrophilic to hydrophobic, the guest-induced structural dynamism of a series of isostructural 5-fold interpenetrated MOFs changed from interpenetration reconstitution to simple framework breathing. [ABSTRACT FROM AUTHOR]

By virtue of planar Cu2(μ-OH)22+ cluster units, a flexible porous metal azolate framework not only adsorbs large amounts of CO2 (19.6 wt% or 266 g L−1 at 298 K and 1 atm) with a high zero-coverage adsorption enthalpy (−47 kJ mol−1), but also desorbs quickly at very low temperatures. [ABSTRACT FROM AUTHOR]

Block-shaped single crystals of the new title compound are synthesized by slow evaporation of the filtrate of an aqueous mixture of Cd(NO3)2, NaN3, and Me4NBr in the ratio of 1:12:6 (20 °C, 55% yield). [ABSTRACT FROM AUTHOR]