Phosphonate monoesters as carboxylate-like linkers for metal organic frameworks

Bidentate phosphonate monoesters are analogues of popular dicarboxylate linkers in MOFs, but with an alkoxy tether close to the coordinating site. Herein, we report 3-D MOF materials based upon phosphonate monoester linkers. Cu(1,4-benzenediphosphonate bis(monoalkyl ester), CuBDPR, with an ethyl tether is nonporous; however, the methyl tether generates an isomorphous framework that is porous and captures CO 2 with a high isosteric heat of adsorption of 45 kJ mol -1. Computational modeling reveals that the CO 2 uptake is extremely sensitive both to the flexing of the structure and to the orientation of the alkyl tether. © 2011 American Chemical Society

Transcriptome analysis of tetrodotoxin sensing and tetrodotoxin action in the central nervous system of tiger puffer Takifugu rubripes juveniles

To reveal the sensing of tetrodotoxin (TTX) by tiger puffer Takifugu rubripes juveniles and its action in the central nervous system (CNS), we conducted transcriptome analysis using next-generation sequencing for the olfactory system and brain of non-toxic cultured juveniles administered TTX. Sixty-seven million reads from the nasal region (olfactory epithelium and skin) and the brain of each of three individuals of the control, TTX-sensing and TTX-administered juveniles were assembled into 153,958 contigs. Mapping raw reads from each sample onto the nucleotide sequences of predicted transcripts in the T. rubripes genome (FUGU version 4) and the de novo assembled contigs to investigate their frequency of expression revealed that the expression of 21 and 81 known genes significantly changed in TTX-sensing and TTX-administered juveniles in comparison with control juveniles, respectively. These genes included those related to feeding regulation and a reward system, and indicated that TTX ingestion of T. rubripes juveniles is controlled in the feeding center in the brain, that T. rubripes may sense TTX as a reward, and that accumulated TTX directly acts on the central nervous system to adjust TTX ingestion

Anhydrous proton conduction at 150\ub0C in a crystalline metal\u2013organic framework

Metal organic frameworks (MOFs) are particularly exciting materials that couple porosity, diversity and crystallinity. But although they have been investigated for a wide range of applications, MOF chemistry focuses almost exclusively on properties intrinsic to the empty frameworks; the use of guest molecules to control functions has been essentially unexamined. Here we report Na3(2,4,6-trihydroxy-1,3,5-benzenetrisulfonate) (named ?-PCMOF2), a MOF that conducts protons in regular one-dimensional pores lined with sulfonate groups. Proton conduction in ?-PCMOF2 was modulated by the controlled loading of 1H-1,2,4-triazole (Tz) guests within the pores and reached 5 10-4 S cm-1 at 150 \ub0C in anhydrous H2, as confirmed by electrical measurements in H2 and D2, and by solid-state NMR spectroscopy. To confirm its potential as a gas separator membrane, the partially loaded MOF (?-PCMOF2(Tz)0.45) was also incorporated into a H2/air membrane electrode assembly. The resulting membrane proved to be gas tight, and gave an open circuit voltage of 1.18 V at 100 \ub0C.Peer reviewed: YesNRC publication: N

Mechanical gas capture and release in a network solid via multiple single-crystalline transformations

Metal\u2013organic frameworks have demonstrated functionality stemming from both robustness and pliancy and as such, offer promise for a broad range of new materials. The flexible aspect of some of these solids is intriguing for so-called 'smart' materials in that they could structurally respond to an external stimulus. Herein, we present an open-channel metal\u2013organic framework that, on dehydration, shifts structure to form closed pores in the solid. This occurs through multiple single-crystal-to-single-crystal transformations such that snapshots of the mechanism of solid-state conversion can be obtained. Notably, the gas composing the atmosphere during dehydration becomes trapped in the closed pores. On rehydration, the pores open to release the trapped gas. Thus, this new material represents a thermally robust and porous material that is also capable of dynamically capturing and releasing gas in a controlled manner.NRC publication: Ye