Minute-MOFs: Ultrafast Synthesis of M2(dobpdc) Metal-Organic Frameworks from Divalent Metal Oxide Colloidal Nanocrystals

The material demands for metal-organic frameworks (MOFs) for next-generation energy-efficient CO capture technologies necessitate advances in their expedient and scalable synthesis. Toward that end, the recently discovered expanded MOF-74, or M (dobpdc), where M = divalent metal cation and dobpdc = 4,4′-dioxido-3,3′-biphenyldicarboxylate, can now be prepared in minutes via a controlled dissolution-crystallization route from divalent metal oxides as precursors. We show that the available surface area of the metal oxide plays a critical role in the precursor dissolution, which was found to be rate-limiting. Based on this understanding of the reaction trajectory, we pushed the chemical transformation to its fringe kinetic limit by configuring the metal oxide precursors as ligand-free colloidal metal oxide nanocrystals, which allowed MOF formation in less than 1 min. MOFs prepared by this strategy were highly crystalline, with BET surface areas on par with conventional multihour syntheses from metal halide salts. This method was also applied successfully in the synthesis of M (dobdc) MOFs, highlighting its generality. Our work challenges the conventional wisdom that plurality of steps in MOF formation is inherently time-intensive. 2 2

Minute-MOFs: Ultrafast Synthesis of M2(dobpdc) Metal-Organic Frameworks from Divalent Metal Oxide Colloidal Nanocrystals

The material demands for metal-organic frameworks (MOFs) for next-generation energy-efficient CO2 capture technologies necessitate advances in their expedient and scalable synthesis. Toward that end, the recently discovered expanded MOF-74, or M2(dobpdc), where M = divalent metal cation and dobpdc = 4,4′-dioxido-3,3′-biphenyldicarboxylate, can now be prepared in minutes via a controlled dissolution-crystallization route from divalent metal oxides as precursors. We show that the available surface area of the metal oxide plays a critical role in the precursor dissolution, which was found to be rate-limiting. Based on this understanding of the reaction trajectory, we pushed the chemical transformation to its fringe kinetic limit by configuring the metal oxide precursors as ligand-free colloidal metal oxide nanocrystals, which allowed MOF formation in less than 1 min. MOFs prepared by this strategy were highly crystalline, with BET surface areas on par with conventional multihour syntheses from metal halide salts. This method was also applied successfully in the synthesis of M2(dobdc) MOFs, highlighting its generality. Our work challenges the conventional wisdom that plurality of steps in MOF formation is inherently time-intensive

Design Rules for Membranes from Polymers of Intrinsic Microporosity for Crossover-free Aqueous Electrochemical Devices

The energy efficiency and cycle life of electrochemical cells with dissolved active materials are inextricably tied to the stability, conductivity, and transport selectivity of the cell's membrane. Membrane design rules have been lacking for such cells operating under harsh conditions, such as high alkalinity, due to the lack of selective, stable membranes. Here, we examined several classes of membranes for three aqueous Zn-based cell chemistries. In doing so, we uncovered a simple relationship between the membrane selectivity and the cell's cycle life, such that it is now possible to predict the lifetime of the cell on the basis of its membrane properties, thus avoiding time- or resource-intensive experimentation in large-format cells. Our work should greatly accelerate the identification of membranes for long-lasting, MW-scale redox-flow, and other low-cost grid batteries, which are required to last 10–20 years

Declining prevalence of HIV-1 drug resistance in antiretroviral treatment-exposed individuals in Western Europe

HIV-1 drug resistance represents a major obstacle to infection and disease control. This retrospective study analyzes trends and determinants of resistance in antiretroviral treatment (ART)-exposed individuals across 7 countries in Europe. Of 20 323 cases, 80% carried at least one resistance mutation: these declined from 81% in 1997 to 71% in 2008. Predicted extensive 3-class resistance was rare (3.2% considering the cumulative genotype) and peaked at 4.5% in 2005, decreasing thereafter. The proportion of cases exhausting available drug options dropped from 32% in 2000 to 1% in 2008. Reduced risk of resistance over calendar years was confirmed by multivariable analysis