Repulsive Lateral Interaction of Water Molecules at the Initial Stages of Adsorption in Microporous AlPO-11 According to Al NMR and DFT.

Lateral (adsorbate-adsorbate) interactions between adsorbed molecules affect various physical and chemical properties of microporous adsorbents and catalysts, influencing their functional properties. In this work, we studied the hydration of microporous AlPO-11 aluminophosphate, which has an unusually ordered structure upon adsorption of water vapor, and according to Al NMR data, only tetrahedrally or octahedrally coordinated Al sites are present in the AlPO-11. These Al NMR data are consistent with the results of density functional theory (DFT) calculations of hydrated AlPO-11, which revealed the presence of a strong repulsive lateral interaction at the initial stage of adsorption, suppressing the adsorption of water on neighboring (separated by one -O-P-O- bridge) Al crystallographic sites.

The impact of framework flexibility and defects on the water adsorption in CAU-10-H.

Aluminum-based metal-organic framework (MOF) CAU-10-H is a promising candidate for heat transformation and water harvesting applications due to its hydrothermal stability, beneficial step-wise water adsorption isotherm and low toxicity. In this study, the effects of the framework flexibility and structural defects on the mechanism of water sorption in CAU-10-H were studied by grand canonical Monte Carlo (GCMC) methods. It was shown by the simulations that the rigid ideal MOF framework is hydrophobic.

Investigation of vanadia-alumina catalysts with solid-state NMR spectroscopy and DFT.

In this work, isolated surface sites of vanadium oxide on the alumina surface were modeled and compared to experimental data obtained with V Solid-State Nuclear Magnetic Resonance (SSNMR) spectroscopy. The geometry of the centers on the (100), (110), and (111) planes of the spinel structure and (010) monoclinic alumina was modeled using density functional theory (DFT); their V NMR parameters were calculated using the Gauge-Including Projector Augmented Wave (GIPAW) method. The comparison of the simulated theoretical spectra with the experimental ones made it possible to find the sites that are likely present on the surface of real catalysts.

Identification of beryllium fluoride complexes in mechanically distorted gels using quadrupolar split Be NMR spectra resolved with solution-state selective cross-polarization.

The uniformly anisotropic media afforded by hydrogels are being increasingly exploited in analytical (structure elucidation) nuclear magnetic resonance (NMR) spectroscopy, and in studies of mechanosensitive biophysical and biochemical properties of living cells. The 9Be NMR parameters of beryllium fluoride complexes formed in aqueous solutions are sensitive markers of the anisotropic molecular environments produced by gelatin gels. The electric quadrupole moment of the 9Be nucleus (spin I = 3/2) interacts with the electric field gradient tensor in a stretched (or compressed) gel, giving rise to the splitting of peaks in 9Be NMR spectra.

Pyrolysis of the Cellulose Fraction of Biomass in the Presence of Solid Acid Catalysts: An Operando Spectroscopy and Theoretical Investigation.

Biomass pyrolysis by solid acid catalysts is one of many promising technologies for sustainable production of hydrocarbon liquid fuels and value-added chemicals, but these complex chemical transformations are still poorly understood. A series of well-defined model SiO -supported alumina catalysts were synthesized and molecularly characterized, under dehydrated conditions and during biomass pyrolysis, with the aim of establishing fundamental catalyst structure-activity/selectivity relationships. The nature and corresponding acidity of the supported AlO nanostructures on SiO were determined with Al/ H NMR and IR spectroscopy of chemisorbed CO, and DFT calculations.

Photochemistry of Dithiocarbamate Cu(SCNEt) Complex in CHCl. Transient Species and TD-DFT Calculations.

Nanosecond laser flash photolysis was used to study the mechanism of photochemical transformations of the diethyldithiocarbamate Cu(II) complex (Cu(dtc), where dtc ≡ SCNEt anion) in chloroform solutions. The electron transfer from the excited Cu(dtc) complex to a solvent molecule leads to the appearance of the primary intermediate, the [ClCu(dtc)(dtcCHCl)] complex, where a dtcCHCl molecule is coordinated with a copper ion via one sulfur atom. In the fast reaction (k = 2.