Water-stable zirconium-based metal-organic framework material with high-surface area and gas-storage capacities.

We designed, synthesized, and characterized a new Zr-based metal-organic framework material, NU-1100, with a pore volume of 1.53 ccg(-1) and Brunauer-Emmett-Teller (BET) surface area of 4020 m(2) g(-1) ; to our knowledge, currently the highest published for Zr-based MOFs. CH4 /CO2 /H2 adsorption isotherms were obtained over a broad range of pressures and temperatures and are in excellent agreement with the computational predictions. The total hydrogen adsorption at 65 bar and 77 K is 0.092 g g(-1) , which corresponds to 43 g L(-1) . The volumetric and gravimetric methane-storage capacities at 65 bar and 298 K are approximately 180 vSTP /v and 0.27 g g(-1) , respectively.OKF, JTH and RQS thank DOE ARPA-E and the Stanford Global Climate and Energy Project for support of work relevant to methane and CO2, respectively. TY acknowledges support by the U. S. Department of Energy through BES Grant No. DE-FG02-08ER46522. WB acknowledges support from the Foundation for Polish Science through the “Kolumb” Program. DFJ acknowledges the Royal Society (UK) for a University Research Fellowship. This material is based upon work supported by the National Science Foundation (grant CHE-1048773).This is the accepted manuscript. The final version is available as 'Water-Stable Zirconium-Based Metal–Organic Framework Material with High-Surface Area and Gas-Storage Capacities' from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/chem.201402895/abstract

1,3,4-Oxadiazoles for Crystal Engineering. Convenient Synthesis and Self-Assembly: Nonchiral Chains versus Chiral Helices

A series of new 1,3,4-oxadiazoles containing carboxylic and halogen groups and a double bond have been synthesized in good yields and a multigram scale. This was achieved at room temperature from readily available 1,2-diacylhydrazines using a cheap condensation reagent (the solution of P₂O₅ in H₂SO₄). Single-crystal X-ray diffraction analysis has shown that all studied 1,3,4-oxadiazole-containing acids are self-assembled by intermolecular H-bonds into supramolecular zigzag chains or helices, depending on the tecton molecular structure and the type of H-bonding. Factors affecting helix formation have been found, and a Cambridge Structural Database (CSD) survey has been performed to support these findings. Moreover, it has been demonstrated that the tuning of the crystal structure leading to spontaneous symmetry breaking for supramolecular helices based on nonchiral molecules is possible even by as little change in molecular structure as a shift from an isopropyl substituent to a cyclopropyl. Subsequently, the studied 1,3,4-oxadiazole-containing acids and related compounds are found to be easily accessible building blocks for crystal engineering of new chiral materials with tunable supramolecular arrangement

1,3,4-Oxadiazoles for Crystal Engineering. Convenient Synthesis and Self-Assembly: Nonchiral Chains versus Chiral Helices

A series of new 1,3,4-oxadiazoles containing carboxylic and halogen groups and a double bond have been synthesized in good yields and a multigram scale. This was achieved at room temperature from readily available 1,2-diacylhydrazines using a cheap condensation reagent (the solution of P₂O₅ in H₂SO₄). Single-crystal X-ray diffraction analysis has shown that all studied 1,3,4-oxadiazole-containing acids are self-assembled by intermolecular H-bonds into supramolecular zigzag chains or helices, depending on the tecton molecular structure and the type of H-bonding. Factors affecting helix formation have been found, and a Cambridge Structural Database (CSD) survey has been performed to support these findings. Moreover, it has been demonstrated that the tuning of the crystal structure leading to spontaneous symmetry breaking for supramolecular helices based on nonchiral molecules is possible even by as little change in molecular structure as a shift from an isopropyl substituent to a cyclopropyl. Subsequently, the studied 1,3,4-oxadiazole-containing acids and related compounds are found to be easily accessible building blocks for crystal engineering of new chiral materials with tunable supramolecular arrangement

Metal–Organic Framework (MOF) Defects under Control: Insights into the Missing Linker Sites and Their Implication in the Reactivity of Zirconium-Based Frameworks

For three-dimensional (3D) metal–organic frameworks (MOFs), the presence and nature of structural defects has been recognized as a key factor shaping the material’s physical and chemical behavior. In this work, the formation of the “missing linker” defects has been addressed in the model biphenyl-4,4′-dicarboxylate (bpdc)-based Zr MOF, UiO-67. The defect showed strong dependence on the nature of the modulator acid used in the MOF synthesis; the defects, in turn, were found to correlate with the MOF physical and chemical properties. The dynamic nature of the Zr6 (node)-monocarboxylate bond showed promise in defect functionalization and “healing”, including the formation of X-ray-quality “defect-free” UiO-67 single crystals. Chemical transformations at defect sites have also been explored. The study was also extended to the isoreticular UiO-66 and UiO-68′ systems

Computational Design of Metal–Organic Frameworks Based on Stable Zirconium Building Units for Storage and Delivery of Methane

A metal–organic framework (MOF) with high volumetric deliverable capacity for methane was synthesized after being identified by computational screening of 204 hypothetical MOF structures featuring (Zr₆O₄)­(OH)₄(CO₂)_n inorganic building blocks. The predicted MOF (<b>NU-800</b>) has an <b>fcu</b> topology in which zirconium nodes are connected via ditopic 1,4-benzenedipropynoic acid linkers. Based on our computer simulations, alkyne groups adjacent to the inorganic zirconium nodes provide more efficient methane packing around the nodes at high pressures. The high predicted gas uptake properties of this new MOF were confirmed by high-pressure isotherm measurements over a large temperature and pressure range. The measured methane deliverable capacity of <b>NU-800</b> between 65 and 5.8 bar is 167 cc­(STP)/cc (0.215 g/g), the highest among zirconium-based MOFs. High-pressure uptake values of H₂ and CO₂ are also among the highest reported. These high gas uptake characteristics, along with the expected highly stable structure of <b>NU-800</b>, make it a promising material for gas storage applications

N‑Phosphorylated Azolylidenes: Novel Ligands for Dinuclear Complexes of Coinage Metals

Dinuclear silver­(I) complexes with bridging N-phosphorylated azolylidene ligands have been synthesized. Subsequent transfer of the ligands to other group 11 metal centers (Cu, Au) has been accomplished, highlighting the usefulness of the silver complexes as an easy to handle, air- and moisture-stable source of these ligands. Preliminary results indicate that dinuclear copper­(I) complexes with N-phosphorylated imidazolylidene ligands display notable catalytic efficiency in nitrene transfer reactions