In-depth experimental and computational 129Xe NMR analysis of extraordinarily efficient adsorption of xenon in a porous organic cage.

Thermal modification is an environmentally friendly process that enhances the lifetime and properties of timber. In this work, the absorption of water in pine wood ( Pinus sylvestris ) samples, which were modified by the ThermoWood process, was studied by magnetic resonance imaging (MRI) and gravimetric analysis. The modification temperatures were varied between 180 ° C and 240 ° C. The data shows that the modification at 240 ° C and at 230 ° C decreases the water absorption rate significantly and slightly, respectively, while lower temperatures do not have a noticeable effect. MR images reveal that free water absorption in latewood (LW) is faster than in earlywood (EW), but in the saturated sample, the amount of water is greater in EW. Individual resin channels can be resolved in the high-resolution images, especially in LW regions of the modified samples, and their density was estimated to be (2.7 ± 0.6) mm -2 . The T 2 relaxation time of water is longer in the modified wood than in the reference samples due to the removal of resin and extractives in the course of the modification process.

Wood decay is an economically significant process, as it is one of the major causes of wood deterioration in buildings. In this study, the decay process of Scots pine (Pinus sylvestris) samples caused by cellar fungus (Coniophora puteana) was followed by nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) methods. Altogether, 30 wood sample pieces were exposed to fungus for 10 weeks. Based on the decrease of the dry mass, the samples were categorized into three classes: decomposed (mass decrease 50–70%), slightly decomposed (10–50%), and nondecomposed (<10%). MRI made it possible to identify the active regions of fungus inside the wood samples based on the signal of free water brought by the fungus and arisen from the decomposition of wood carbohydrates. MRI implies that free water is not only created by the decay process, but fungal hyphae also transports a significant amount of water into the sample. Two-dimensional 1H T1-T2 relaxation correlation NMR measurements provided detailed information about the changes in the microstructure of wood due to fungal decomposition. Overall, this study paves the way for noninvasive NMR and MRI detection of fungal decay at early stages as well as the related structural changes.

aWe demonstrate the ability of multidimensional Laplace NMR (LNMR), comprising relaxation and diffusion experiments, to reveal essential information about microscopic phase structures and dynamics of ionic liquids that is not observable using conventional NMR spectroscopy or other techniques.Ionic liquids (ILs) are salts that consist of ions and have, by definition, melting points below 100 1C. They have unique physical and chemical properties such as high ionic conductivity, negligible vapour pressure, nonflammability, broad liquid phase temperature ranges, and high thermal stability, which all make ILs attractive in many scientific and technological applications. The applications include organic synthesis and catalysis, gas separation, extraction of metals, lubrication, electrochemistry, crystallization media for pharmaceutically active compounds and functional materials, etc. 1 NMR relaxation and diffusion experiments provide versatile information about the dynamics and structure of substances such as proteins, polymers, liquid crystals and porous media.2 They may also improve chemical resolution by distinguishing different components in complex systems without spectral resolution. 3 The relaxation and diffusion data consist of exponentially decaying components and the processing requires a Laplace inversion in order to determine diffusion coefficient and relaxation time distributions. 2 Therefore, these methods are referred to as Laplace NMR (LNMR). Like in traditional NMR spectroscopy, a multidimensional approach significantly enhances the resolution and information content of LNMR. 4 The approach makes it possible to correlate diffusion coefficients and relaxation times, and enables the investigation of chemical exchange even in the case when the exchanging sites are not resolved in the spectrum. The method requires a reliable and robust multidimensional Laplace inversion algorithm for extracting the diffusion coefficient and relaxation time distributions from the experimental data. 5NMR relaxation and diffusion experiments have been widely used to investigate physicochemical properties, hydrogen bonding, aggregation, solvation dynamics and atomic level interactions of ILs.6 However, to the best of our knowledge, the ability of Laplace inversion algorithms to provide distributions of relaxation times and diffusion coefficients has not yet exploited in studies of ILs. Furthermore, the potential of multidimensional LNMR to provide unique information about correlations and exchange is yet unexplored in the IL context. In this work, we demonstrate that a combination of several one-dimensional (1D) and two-dimensional (2D) LNMR experiments can provide important microscopic information about the phase structures of ILs, which is not possible using conventional NMR spectroscopy or other methods. We concentrate on the investigation of a halogen-free orthoborate based ionic liquid (hf-BIL).7 The affinity to absorb water, high polarity and toxicity make halogen containing ILs undesirable in many applications, and h...

Thermally modified wood (TMW) is widely used in outdoor applications due to its advanced properties towards weathering stresses. Although the structure changes of TMW from weather factors have been reported, investigation of the quantitative analysis of water states and cell wall structure of TMW after weathering is limited. In this work, the amount of bound water, fiber saturation point (FSP), cell wall pores, and free water distribution of thermally modified Scots pine, Norway spruce, and European ash were measured before and after a 2-year natural weathering via NMR relaxometry, cryoporometry, and magnetic resonance imaging. The results show that weathering increased T 2 relaxation time of lumens, indicating the degradation of tracheids and vessels, especially in TMW compared to unmodified wood. The amounts of bound water, FSP value, and cell wall pores were increased after weathering; however, an increase in thermal modification intensity resulted in lower FSP and limited the increase in number of pores. In summary, TMW showed better performance than unmodified wood after weathering. Keywords Bound water Á Free water Á Fiber saturation point (FSP) Á Cell wall pores Á Nuclear magnetic resonance (NMR) Á Thermally modified wood

The dynamics of gas in CC3 porous solid is explored with NMR diffusion and relaxation experiments and interpreted with molecular level modeling.

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