As compared to porous network solids, including metal–organic frameworks, covalent–organic frameworks, porous aromatic frameworks, and zeolites, porous molecular materials are relatively unexplored. ...Additionally, within porous molecular space, porous organic cages (POCs) have been the most widely reported over the past decade. Relatively recently, however, porous hybrid metal–organic molecular complexes have received considerable attention with a large fraction of surface areas for these coordination cages reported over the past three years. This review focuses on advances in this area. We highlight the recent work with permanently microporous metal–organic polyhedra (MOPs). Analogous to early work in the area of MOFs, the vast majority of MOPs for which surface areas have been reported have been based on paddlewheel building units and carboxylate ligands. We describe the synthesis of porous cages and highlight those based on monometallic, bimetallic, trimetallic, tetrametallic, and higher nuclearity clusters. Finally, we showcase work wherein the porosity of MOPs has been leveraged for applications related to the storage and separation of small molecules and the incorporation of these porous and potentially porous cages into membranes.
Although gas adsorption properties of extended three-dimensional metal–organic materials have been widely studied, they remain relatively unexplored in porous molecular systems. This is particularly ...the case for porous coordination cages for which surface areas are typically not reported. Herein, we report the synthesis, characterization, activation, and gas adsorption properties of a family of carbazole-based cages. The chromium analog displays a coordination cage record BET (Brunauer−Emmett−Teller) surface area of 1235 m2/g. With precise synthesis and activation procedures, two previously reported cages similarly display high surface areas. The materials exhibit high methane adsorption capacities at 65 bar with the chromium(II) cage displaying CH4 capacities of 194 cm3/g and 148 cm3/cm3. This high uptake is a result of optimal pore design, which was confirmed via powder neutron diffraction experiments.
Posttraumatic stress symptoms (PTSS) are common after acute coronary syndrome (ACS) and predict increased morbidity and mortality. Climate change contributes to worse mental and cardiovascular health ...outcomes, thus, PTSS represent a potential mechanism linking climate change to adverse cardiovascular outcomes. Because people living in areas with lower socioeconomic status (SES) experience greater climate vulnerability, have worse cardiovascular health, and may be more susceptible to PTSS, any effect of temperature on PTSS could be amplified in this population.
Spatial regression models were estimated to test the association of temperature and temperature variability (within-day variability, directed change over time, and absolute change over time), census tract-level SES, and their interaction with PTSS 1 month post-hospital discharge in a longitudinal cohort study comprising 956 patients evaluated for ACS at an urban U.S. academic medical center between November 2013-May 2017. PTSS were self-reported in relation to the ACS event that brought the patient to the hospital. Census tract-level was computed as a composite score from the CDC Social Vulnerability Index, with higher values indicating lower SES.
No temperature or temperature variability metrics were associated with PTSS. Lower census tract-level SES was associated with greater PTSS at 1 month. There was a marginally significant interaction of SES with ACS status, such that we only observed evidence of an association among those with ACS.
Temperature exposures were not associated with acute CVD-induced PTSS, which could be a result of a small sample size, mismatched timescale, or lack of a true effect. Conversely, lower census tract-level SES was associated with developing worse PTSS 1 month after evaluation for an ACS. This association appeared stronger in individuals with a true ACS. Early interventions to prevent PTSS could promote better mental and CVD outcomes in this at-risk population.
Coordination assemblies containing transition-metal cations with coordinatively unsaturated sites remain a challenging target in the synthesis of porous molecules. Herein, we report the design, ...synthesis, and characterization of three porous hybrid inorganic/organic porous molecular assemblies based on cobalt(II) and nickel(II). Precise tuning of ligand functionalization allows for the isolation of molecular species in addition to two- and three-dimensional metal–organic frameworks. The cobaltous and nickelous cage compounds display excellent thermal stabilities in excess of 473 K and Brunauer–Emmett–Teller surface areas on the order of 200 m2/g. The precise ligand functionalization utilized here to control phases between discrete molecules and higher-dimensional solids can potentially further be tuned to optimize the porosity and solubility in future molecular systems.
A subset of coordination cages have garnered considerable recent attention for their potential permanent porosity in the solid state. Herein, we report a series of functionalized carbazole-based ...cages of the structure type M
12
(R-cdc)
12
(M = Cr, Cu, Mo) where the functional groups include a range of aromatic substituents. Single-crystal X-ray structure determinations reveal a variety of intercage interactions in these materials, largely governed by pi-pi stacking. Density functional theory for a subset of these cages was used to confirm that the nature of the increased stability of aryl-functionalized cages is a result of inter-cage ligand interactions.
Straightforward coupling reactions give access to aryl-functionalized ligands for the synthesis of porous coordination cages with tunable properties and increased stability.
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•Traffic-related air pollution (using NO2 as a surrogate) can trigger heart attacks.•It is not clear how soon after exposure a heart attack might occur.•We found that traffic-related ...pollution can trigger heart attacks within 6 h.•Risk was elevated at pollution concentrations below air quality standards.
Traffic-related air pollution can trigger myocardial infarction (MI). However, the hourly hazard period of exposure to nitrogen dioxide (NO2), a common traffic tracer, for incident MI has not been fully evaluated. Thus, the current hourly US national air quality standard (100 ppb) is based on limited hourly-level effect estimates, which may not adequately protect cardiovascular health.
We characterized the hourly hazard period of NO2 exposure for MI in New York state (NYS), USA, from 2000 to 2015.
For nine cities in NYS, we obtained data on MI hospitalizations from the NYS Department of Health Statewide Planning and Research Cooperative System and hourly NO2 concentrations from the US Environmental Protection Agency’s Air Quality System database. We used city-wide exposures and a case-crossover study design with distributed lag non-linear terms to assess the relationship between hourly NO2 concentrations over 24 h and MI, adjusting for hourly temperature and relative humidity.
The mean NO2 concentration was 23.2 ppb (standard deviation: 12.6 ppb). In the six hours preceding MI, we found linearly increased risk with increasing NO2 concentrations. At lag hour 0, a 10 ppb increase in NO2 was associated with 0.2 % increased risk of MI (Rate Ratio RR: 1.002; 95 % Confidence Interval CI: 1.000, 1.004). We estimated a cumulative RR of 1.015 (95 % CI: 1.008, 1.021) for all 24 lag hours per 10 ppb increase in NO2. Lag hours 2–3 had consistently elevated risk ratios in sensitivity analyses.
We found robust associations between hourly NO2 exposure and MI risk at concentrations far lower than current hourly NO2 national standards. Risk of MI was most elevated in the six hours after exposure, consistent with prior studies and experimental work evaluating physiologic responses after acute traffic exposure. Our findings suggest that current hourly standards may be insufficient to protect cardiovascular health.
Porous molecular solids are promising materials for gas storage and gas separation applications. However, given the relative dearth of structural information concerning these materials, additional ...studies are vital for further understanding their properties and developing design parameters for their optimization. Here, we examine a series of isostructural cuboctahedral, paddlewheel-based coordination cages, M24(tBu-bdc)24 (M = Cr, Mo, Ru; tBu-bdc2– = 5-tert-butylisophthalate), for high-pressure methane storage. As the decrease in crystallinity upon activation of these porous molecular materials precludes diffraction studies, we turn to a related class of pillared coordination cage-based metal–organic frameworks, M24(Me-bdc)24(dabco)6 (M = Fe, Co; Me-bdc2– = 5-methylisophthalate; dabco = 1,4-diazabicyclo2.2.2octane) for neutron diffraction studies. The five porous materials display BET surface areas from 1057–1937 m2/g and total methane uptake capacities of up to 143 cm3(STP)/cm3. Both the porous cages and cage-based frameworks display methane adsorption enthalpies of −15 to −22 kJ/mol. Also supported by molecular modeling, neutron diffraction studies indicate that the triangular windows of the cage are favorable methane adsorption sites with CD4–arene interactions between 3.7 and 4.1 Å. At both low and high loadings, two additional methane adsorption sites on the exterior surface of the cage are apparent for a total of 56 adsorption sites per cage. These results show that M24L24 cages are competent gas storage materials and further adsorption sites may be optimized by judicious ligand functionalization to control extracage pore space.
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In the United States (US), urinary tract infections (UTI) lead to more than 10 million office visits each year. Temperature and season are potentially important risk factors for UTI, ...particularly in the context of climate change.
We examined the relationship between ambient temperature and outpatient UTI diagnoses among patients followed from 2015 to 2017 in two California healthcare systems: Kaiser Permanente Southern California (KPSC) and Sutter Health in Northern California. We identified UTI diagnoses in adult patients using diagnostic codes and laboratory records from electronic health records. We abstracted patient age, sex, season of diagnosis, and linked community-level Index of Concentration at the Extremes (ICE-I, a measure of wealth and poverty concentration) based on residential address. Daily county-level average ambient temperature was assembled from the Parameter-elevation Regressions on Independent Slopes Model (PRISM). We implemented distributed lag nonlinear models (DLNM) to assess the association between UTI and lagged daily temperatures. Main analyses were confined to women. In secondary analyses, we stratified by season, healthcare system, and community-level ICE-I.
We observed 787,186 UTI cases (89% among women). We observed a threshold association between ambient temperature and UTI among women: an increase in daily temperature from the 5th percentile (6.0 ˚C) to the mean (16.2 ˚C) was associated with a 3.2% (95% CI: 2.4, 3.9%) increase in same-day UTI diagnosis rate, whereas an increase from the mean to 95th percentile was associated with no change in UTI risk (0.0%, 95% CI: −0.7, 0.6%). In secondary analyses, we observed the clearest monotonic increase in the rate of UTI diagnosis with higher temperatures in the fall. Associations did not differ meaningfully by healthcare system or community-level ICE-I. Results were robust to alternate model specifications.
Increasing temperature was related to higher rate of outpatient UTI, particularly in the shoulder seasons (spring, autumn).
The molecular nature, and thus potential solubility, of coordination cages endows them with a number of advantages as compared to metal-organic frameworks and other extended network solids. However, ...their lack of three-dimensional connectivity typically limits their thermal stability as inter-cage interactions in these materials are relatively weak. This is particularly the case for carbazole-based coordination cages. Here, we report the design and synthesis of a benzyl-functionalized octahedral coordination cage that displays moderate surface area and increased thermal stability as compared to its unfunctionalized counterpart. Structural analysis suggests the increased thermal stability is a result of aryl-aryl interactions between ligand groups on adjacent cages. We have further adapted the ligand synthesis strategy to afford a novel, high-yielding preparatory route for the isolation of carbazole-3,6-dicarboxylic acid that does not rely on pyrophoric reagents or transition metal catalysts.
A benzyl-protecting strategy affords access to large quantities of carbazole-based ligands or molecular adsorbents with tunable inter-cage interactions.
Porosity in low-nuclearity coordination cages is relatively rare as cages with larger pore sizes are usually targeted as a way to increase gas adsorption capabilities in this promising class of ...molecular adsorbents. This work presents the design, synthesis, and characterization of a series of carbazole dicarboxylic acid bridged calixarene capped cages that exhibit significant porosity to N
2
and CO
2
given their limited size, presenting with Braun-Emmett-Teller (BET) surface areas in excess of 450 m
2
g
−1
and 350 m
2
g
−1
, respectively. Furthermore, we report, to the best of our knowledge, the first class of calixarene capped cages bridged by a ligand with a 90° bridging angle in addition to the first permanently porous calixarene cage to utilize Mn
2+
cations.
Porosity in low-nuclearity coordination cages is relatively rare as cages with larger pore sizes are usually targeted as a way to increase gas adsorption capabilities in this promising class of molecular adsorbents.
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