Diamonds are forever: A diamond‐like framework in which the C–C bonds are replaced with rigid phenyl rings (see picture) is not only structurally stable but also has a large internal surface area. This porous aromatic framework (PAF‐1) demonstrates high uptake capacities of hydrogen and carbon dioxide as well as benzene and toluene vapors, and has an unprecedented surface area of 7100 m2 g−1.

A series of isostructural metal-organic framework polymers of composition [Cu2(L)(H2O)2] (L= tetracarboxylate ligands), denoted NOTT-nnn, has been synthesized and characterized. Single crystal X-ray structures confirm the complexes to contain binuclear Cu(II) paddlewheel nodes each bridged by four carboxylate centers to give a NbO-type network of 64.82 topology. These complexes are activated by solvent exchange with acetone coupled to heating cycles under vacuum to afford the desolvated porous materials NOTT-100 to NOTT-109. These incorporate a vacant coordination site at each Cu(II) center and have large pore volumes that contribute to the observed high H2 adsorption. Indeed, NOTT-103 at 77 K and 60 bar shows a very high total H2 adsorption of 77.8 mg g(-)- equivalent to 7.78 wt% [wt% = (weight of adsorbed H2)/(weight of host material)] or 7.22 wt% [wt% = 100(weight of adsorbed H2)/(weight of host material + weight of adsorbed H2)]. Neutron powder diffraction studies on NOTT-101 reveal three adsorption sites for this material: at the exposed Cu(II) coordination site, at the pocket formed by three {Cu2} paddle wheels, and at the cusp of three phenyl rings. Systematic virial analysis of the H2 isotherms suggests that the H2 binding energies at these sites are very similar and the differences are smaller than 1.0 kJ mol-1, although the adsorption enthalpies for H2 at the exposed Cu(II) site are significantly affected by pore metrics. Introducing methyl groups or using kinked ligands to create smaller pores can enhance the isosteric heat of adsorption and improve H2 adsorption. However, although increasing the overlap of potential energy fields of pore walls increases the heat of H2 adsorption at low pressure, it may be detrimental to the overall adsorption capacity by reducing the pore volume.

Abstract:A microporous metal-organic framework, PCN-14, based on an anthracene derivative, 5,5′-(9,10-anthracenediyl)di-isophthalate (H4adip), was synthesized under solvothermal reaction conditions. X-ray single crystal analysis revealed that PCN-14 consists of nanoscopic cages suitable for gas storage. N2-adsorption studies of PCN-14 at 77 K reveal a Langmuir surface area of 2176 m 2 /g and a pore volume of 0.87 cm 3 /g. Methane adsorption studies at 290 K and 35 bar show that PCN-14 exhibits an absolute methane-adsorption capacity of 230 v/v, 28% higher than the DOE target (180 v/v) for methane storage.

We report a detailed study of CO2 adsorption in two important metal−organic framework (MOF) compounds (Mg-MOF-74 and HKUST-1). In both MOFs, the open metal ions were identified as the primary binding sites through neutron diffraction measurements. The relatively strong metal−CO2 binding was attributed to an enhanced electrostatic interaction, and vibrational mode analysis shows that the adsorbed CO2 molecule is strongly attached through one of its oxygen atoms while the rest of the molecule is relatively free. This high orientational disorder is the reason for the large apparent O−C−O bond bending angle derived from diffraction measurements. Our calculations give only a small degree of bond bending, suggesting that the CO2 adsorption on the open metal site is still largely physisorption. Interestingly, the overall metal−CO2 binding strength is right in the range which can facilitate both adsorption (CO2 capture) and desorption (MOF regeneration) under typical flue gas conditions.

Metal-organic frameworks (MOFs) have been shown to be excellent materials for storage of carbon dioxide, implying that they could be useful for removal of carbon dioxide from flue gas stacks, however their performance in industrially relevant swing adsorption processes for carbon capture has not been studied. Here we show that the efficacy of MOFs for carbon capture depends dramatically on the process and that some MOFs can provide significant carbon capture under typical pressure and vacuum swing processes. In particular, MOFs that possess coordinatively unsaturated metal centers offer as much as 9 mmol g À1 swing capacity under certain conditions. The results herein clearly show that there is no single ideal compound for carbon capture applications and that different materials can perform better or worse depending on the specific process conditions. In addition to their capture performances, we have also investigated their selectivity to carbon dioxide over that of nitrogen and methane. The analysis provided clearly demonstrates that the performance of a given MOF cannot be determined without also considering the detailed industrial process in which the MOF is to be applied.

A promising storage medium for hydrogen and other gases is a graphene oxide framework (GOF) that consists of layers of GO connected by benzene‐1,4‐diboronic acid (B14DBA) pillars (see picture). Theoretical predictions and the initial experimental results are presented for this cheap and environmentally friendly building block for nanoporous materials with better gas adsorption properties.

The online social network Twitter has grown exponentially since 2008. The current study examined Twitter use among professional athletes who use Twitter to communicate with fans and other players. The study used content analysis to place 1,962 tweets by professional athletes into one of six categories: interactivity, diversion, information sharing, content, promotional, and fanship. Many of the tweets fell into the interactivity category (34%). Athletes used Twitter to converse directly with their followers. Those with the most followers had more interactivity tweets. A large percentage of tweets (28%) fell into the diversion category, because many of the tweets involved non-sports-related topics, and relatively few of the tweets (15%) involved players discussing their own teams or sports. In addition, only 5% of the tweets were promotional in nature, indicating that professional athletes may not be taking advantage of the promotional opportunities Twitter may provide.

Diamantenfieber: Ein Diamantgerüst, in dem C‐C‐Bindungen gegen Benzolringe ausgetauscht sind (siehe Bild), ist einerseits stabil und hat andererseits eine große innere Oberfläche. Das poröse aromatische Gerüst PAF‐1 (Oberfläche 7100 m2 g−1) kann große Mengen an Wasserstoff und Kohlendioxid, Benzol‐ und Toluoldampf aufnehmen.