Role of crystal size on swing-effect and adsorption induced structure transition of ZIF-8.

The flexibility and structure transition behaviour of ZIF-8 in a series of samples with different particle size has been studied using a combination of high-resolution N2 gas adsorption isotherms and, for the first time, a broad in situ PXRD and Rietveld analysis. During the stepped adsorption process, large particles showed a narrow adsorption/desorption pressure range with a shorter equilibrium time due to lower kinetic hindrance, deriving from higher amount of active sites. In situ PXRD showed that both the rotation of imidazole ring and a bend in the methyl group led to the gate opening of ZIF-8.This work was funded by the EPSRC IAA Partnership Development Award (RG/75759). D.F.-J. thanks the Royal Society for funding through a University Research Fellowship. We thank Diamond Light Source for beamtime at beamline I11 (visit EE9750).This is the author accepted manuscript. The final version is available from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C6DT00565

Alkaline-earth phosphonate MOFs with reversible hydration-dependent fluorescence

A new rigid tritopic phosphonic ligand, 2,4,6-tris(4-phosphonophenyl)pyridine (H6L), was synthesized and used to assemble isostructural barium (1) and strontium (2) phosphonate metal organic frameworks that exhibit fully reversible and selective water-dependent fluorescence red-shift at room temperature

Divalent Metal Vinylphosphonate Layered Materials: Compositional Variability, Structural Peculiarities, Dehydration Behavior, and Photoluminescent Properties

A family of M-VP (M = Ni, Co, Cd, Mn, Zn, Fe, Cu, Pb; VP = vinylphosphonate) and M-PVP (M = Co, Cd; PVP = phenylvinylphosphonate) materials have been synthesized by hydrothermal methods and characterized by FTIR, elemental analysis, and thermogravimetric analysis (TGA). Their structures were determined either by single crystal X-ray crystallography or from laboratory X-ray powder diffraction data. The crystal structure of some M-VP and M-PVP materials is two-dimensional (2D) layered, with the organic groups (vinyl or phenylvinyl) protruding into the interlamellar space. However, the Pb-VP and Cu-VP materials show dramatically different structural features. The porous, three-dimensional (3D) structure of Pb-VP contains the Pb center in a pentagonal pyramid. A Cu-VP variant of the common 2D layered structure shows a very peculiar structure. The structure of the material is 2D with the layers based upon three crystallographically distinct Cu atoms; an octahedrally coordinated Cu2+ atom, a square planar Cu2+ atom and a Cu+ atom. The latter has an unusual co-ordination environment as it is 3-coordinated to two oxygen atoms with the third bond across the double bond of the vinyl group. Metal-coordinated water loss was studied by TGA and thermodiffractometry. The rehydration of the anhydrous phases to give the initial phase takes place rapidly for Cd-PVP but it takes several days for Co-PVP. The M-VP materials exhibit variable dehydration-rehydration behavior, with most of them losing crystallinity during the process.Proyecto nacional MAT2010-15175 (MICINN, España

Generating large starting configurations for molecular Reverse Monte Carlo modelling of an unique non-linear optical amorphous solid

We report on the recent advances regarding the source code optimization of Reverse Monte Carlo modelling used in scattering data analysis of an amorphous molecular solid which has recently attracted attention as a new brilliant white light emitter if irradiated by a simple infrared laser diode. The algorithm used for generating random molecular starting configurations without overlapping molecules in a box with periodic boundary conditions has been accelerated by a factor of roughly 400 in a 54k atom case. The resulting bigger independent starting configurations are used to gain further insight into previously presented x-ray scattering data. New improved scattering data have been obtained, revealing new structural features in the lower Q range

A titanium(IV)-based metal-organic framework featuring defect-rich Ti-O sheets as an oxidative desulfurization catalyst

While titanium‐based metal–organic frameworks (MOFs) have been widely studied for their (photo)catalytic potential, only a few TiIV MOFs have been reported owing to the high reactivity of the employed titanium precursors. The synthesis of COK‐47 is now presented, the first Ti carboxylate MOF based on sheets of TiIVO6 octahedra, which can be synthesized with a range of different linkers. COK‐47 can be synthesized as an inherently defective nanoparticulate material, rendering it a highly efficient catalyst for the oxidation of thiophenes. Its structure was determined by continuous rotation electron diffraction and studied in depth by X‐ray total scattering, EXAFS, and solid‐state NMR. Furthermore, its photoactivity was investigated by electron paramagnetic resonance and demonstrated by catalytic photodegradation of rhodamine 6G

Atrioventricular node ablation is an effective management strategy for atrial fibrillation in patients with hypertrophic cardiomyopathy

BACKGROUND: Atrial fibrillation (AF) is common in hypertrophic cardiomyopathy (HCM) patients and can be challenging to manage. Atrioventricular node (AVN) ablation may be an effective management strategy for AF in these patients. OBJECTIVE: Assess the efficacy of AVN ablation in HCM patients who have failed medical therapy and/or catheter ablation for AF. METHODS: Multi-centre study with retrospective analysis of a prospectively collated HCM registry. AVN ablation patients were identified. Baseline characteristics, device and procedural indication were collected. Symptoms defined by NYHA and EHRA classification and echocardiographic findings during follow-up were assessed. RESULTS: Fifty-nine patients were included. Indications for AVN ablation were: 6 (10.2%) inappropriate ICD shock, 35 (59.3%) ineffective rate control and 18 (30.5%) to regularize rhythm to improve symptoms. During post-AVN ablation follow-up of (79.4±61.1 months), left ventricular ejection fraction (LVEF) remained stable (pre-LVEF 48.9±12.4%, post-LVEF 49.8±10.9%, p=0.68) even in those without a CRT device (pre-LVEF 54.3±8.0% vs post-LVEF 53.8±8.0%=0.65). Forty-nine (83.1%) patients reported an improvement in symptoms regardless of AF type (17/21, 81.0% paroxysmal vs. 32/38, 84.2% persistent AF; p=1.00), presence of baseline LV impairment (22/26, 84.6% LVEF≤50% vs. 27/33, 81.8% LVEF≥50%; p=1.00) or CRT device (27/32, 84.4% CRT vs. 22/27, 81.5% no CRT; p=1.0). Symptoms improved in 16 (89%) patients who underwent AVN ablation to regularize rhythm. CONCLUSION: AVN ablation improved symptoms without impacting LV function in a majority of the patients. AVN ablation is suggestive to be an effective and safe management approach for AF in HCM and should be further evaluated in larger prospective studies