Disordered compounds are crucially important for fundamental science and industrial applications. Yet most available methods to explore solid-state material properties require ideal periodicity, which, strictly speaking, does not exist in this type of materials. The supercell approximation is a way imply periodicity disordered systems while preserving "disordered" at the local level. Although approach very common, reported research still uses supercells that constructed "by hand" ad-hoc.This...

Cation ordering is believed to have crucial effects on many of the physicochemical properties that make layered double hydroxides (LDHs) materials considerable interest as host structures for drug delivery systems, nanocomposite materials, or catalysis. Here we first unambiguously confirm solid-state 1H NMR at fast (60–65 kHz) magic-angle spinning (MAS) can be used distinguish and quantify different local MgnAl3–nOH (n = 1, 2, 3) environments hydroxyl groups in LDH layers. By combining 27Al...

A (13)C CPMAS NMR experiment at high field (11.7 T) has produced significantly improved dispersion for the alpha form of testosterone, allowing revisions and extensions to be made assignments. Correlations shown by an INADEQUATE two-dimensional spectrum, recorded 16.5 T, have allowed components most doublet signals grouped into two sets (for crystallographically independent molecules). First-principles computations, employing a fully solid-state approach, been used obtain values...

A general protocol for the structural characterization of paramagnetic molecular solids using solid-state NMR is provided and illustrated by a high-spin FeII catalyst precursor. We show how good performance can be obtained on powder sample at natural abundance very fast (>30 kHz) magic angle spinning (MAS), even though individual resonances have highly anisotropic shifts short relaxation times. The results include optimization broadband heteronuclear (proton-carbon) recoupling sequences...

We present a detailed investigation of the molecular structure montmorillonite, an aluminosilicate clay with important applications in materials sciences, such as for catalysis, drug delivery, or waste barrier. Solid-state 29Si, 27Al, 25Mg, and 1H nuclear magnetic resonance (NMR) measurements combined density functional theory (DFT) calculations provide comprehensive picture local composition synthetic its naturally occurring analogue. A revised is proposed based on NMR results that allow...

A general protocol is demonstrated for determining the structures of molecularly ordered but noncrystalline solids, which combines constraints provided by X-ray diffraction (XRD), one- and two-dimensional solid-state nuclear magnetic resonance (NMR) spectroscopy, first-principles quantum chemical calculations. The approach used to determine structure(s) a surfactant-directed layered silicate with short-range order in two dimensions without long-range periodicity three-dimensions (3D)....

The (13)C CPMAS spectrum is presented for the polymorph of oxybuprocaine hydrochloride which stable at room temperature, i.e. Mod. II degrees . It shows crystallographic splittings arising from fact that there are two molecules, with substantially different conformations, in asymmetric unit. An INADEQUATE two-dimensional experiment was used to link signals same independent molecule. chemical shifts discussed relation crystal structure. Of four ethyl groups attached NH(+) nitrogens, one gives...

Subtle structural details of siliceous zeolites are probed by using two-bond scalar (J) coupling constants to characterize covalently bonded 29Si–O–29Si site pairs and local framework order. Solid-state two-dimensional (2D) 29Si{29Si} NMR measurements first-principles calculations 2J(29Si–O–29Si) couplings shed insights on both the structures Sigma-2 ZSM-12, as well sensitivity J for detailed characterization analyses. DFT a model linear silicate dimer show that 2J(Si–O–Si) have complicated...

Unlike the long-range order of ideal crystalline structures, local is an intrinsic characteristic real materials and often serves as key to tuning their properties final applications. Although researchers can easily assess ordering using two-dimensional imaging techniques with resolution that approaches atomic level, diagnosis, description, qualification in three dimensions much more challenging. Solid-state nuclear magnetic resonance (NMR) its panel continually developing instruments...

We show how two-dimensional chemical shift conditional probability distributions can be extracted from experimental NMR correlation spectra of disordered solids. that transverse dephasing times are central importance in determining the resolution (and sensitivity) these distributions. These provide a new source structural information characteristic solids, which is much more sensitive to structure than individual-atom The contained clearly potentially extremely rich for understanding...

Size-controlled ZnSe nanoparticles with high extents of atomic positional order are shown to exhibit large size-dependent variations in their local electronic environments. Solid-state ;{77}Se and ;{67}Zn NMR spectra reveal increasingly broad distributions environments decreasing nanoparticle sizes, contrast degrees established by transmission electron microscopy x-ray diffraction. First-principles calculations parameters distinguish between disorder that propagate from the surfaces yield...

Local compositions and structures of ${\text{Zn}}_{1\ensuremath{-}x}{\text{Mg}}_{x}\text{O}$ alloys have been investigated by Raman solid-state $^{67}\text{Z}\text{n}/^{25}\text{M}\text{g}$ nuclear-magnetic-resonance (NMR) spectroscopies neutron pair-distribution-function (PDF) analyses. The ${E}_{2}^{\text{low}}$ ${E}_{2}^{\text{high}}$ modes display Gaussian- Lorentzian-type profiles, respectively. At higher Mg substitutions, both become broader, while their peak positions shift in...

A general approach for structural interpretation of local disorder in partially ordered solids is proposed, combining high-resolution two-dimensional (2D) nuclear magnetic resonance (NMR) and first principles calculations. We show that small chemical shift variations the order a ppm can be interpreted detailed terms with advanced density functional theory methods. Focusing on model system bisphosphinoamine, we demonstrate existence spatial range amplitude probed using quantitative...

Measuring internuclear distances through dipolar interaction is a major challenge for solid-state nuclear magnetic resonance (NMR) spectroscopy. Obtaining reliable interatomic provides an access to the local structure in ordered or disordered solids. We show that at magic angle spinning (MAS) frequencies larger than ca. 50 kHz, some of three-spin terms homogeneous homonuclear Hamiltonian can be used promote creation double-quantum coherences between neighbouring 1H 19F spins without using...

Improvement of the industrial electrolytic process for aluminum production necessitates a thorough understanding underlying ionic structure electrolyte, which mainly comprises NaF and AlF3 at around 965 °C. The chemical physical properties this melt strongly depend on speciation, requires multipronged approach in order to clarify its properties. Here we parametrize new polarizable ion model (PIM) interatomic potential molten NaF–AlF3 system, is used study liquid up 50 mol % high...

Scalar (J) couplings in solid-state NMR spectroscopy are sensitive to covalent through-bond interactions that make them informative structural probes for a wide range of complex materials. Until now, however, they have been generally unsuitable use isotopically enriched solids, such as proteins or many inorganic because the complications presented by multiple coupled but nonisolated spins. Such difficulties overcome incorporating z-filter results robust method measuring pure J-coupling...

Surfactant-templated layered silicates are shown to possess complex compositional, structural, and dynamic features that manifest rich interrelated order disorder at molecular length scales. Temperature-dependent 1D 2D solid-state 29Si NMR measurements reveal a chemical-exchange process involving the surfactant headgroups is concomitant with reversible broadening of line shapes under magic-angle-spinning (MAS) conditions temperatures in range 205−330 K. Specifically, temperature-dependent...

This article reports on the identification, synthesis, and in-situ structure determination of a new crystalline calcium borosilicate compound composition CaSi(1/3)B(2/3)O(8/3). Synthesis was carried out by complete crystallization annealing from corresponding glassy in widely studied CaO-SiO2-B2O3 ternary system. The crystallographic determined ab initio using electron diffraction information charge flipping algorithm performed synchrotron neutron powder data collected situ at high...

Co-self-assembly of mesostructured silica films from solutions tetrahydrofuran (THF) and water, precursor species, structure-directing Pluronic P123 block-copolymer molecules is reported with without conjugated polymer guest species. The solution-phase behavior the ternary THF−water−P123 system guided selection nonequilibrium synthesis conditions that allowed highly ordered 2D hexagonal or lamellar to be prepared. Dilute water produced in situ by condensation were necessary sufficient...

This study is focused on structural characterization of hybrid glasses obtained by consolidation melting gels. The gels were prepared in molar ratios methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES) 75%MTES-25%DMDES 65%MTES-35%DMDES. Following consolidation, the characterized using Raman, 29Si 13C Nuclear Magnetic Resonance (NMR) spectroscopies, synchrotron Small Angle X-Ray Scattering (SAXS) scanning electron microscopy (SEM). Raman spectroscopy revealed presence Si-C bonds...

The aggregation of surfactants on solid surfaces as they are adsorbed from solution is the basis numerous technological applications such colloidal stabilization, ore flotation, and floor cleaning. understanding both structure dynamics surfactant aggregates applies to development alternative ways preparing hybrid layered materials. For this purpose, we study adsorption triethylene glycol mono n-decyl ether (C10E3) nonionic onto a synthetic montmorillonite (Mt), an aluminosilicate clay...

The measurement of scalar (J) couplings by solid-state NMR is a field great interest, since this interaction rich source local structural information, complementary to dipolar and chemical shift interactions. Here, we first demonstrate that J-coupling distributions exist can be observed in disordered solids, as illustrated with the observation pair-specific distribution (2)J((31)P-N-(31)P) bis-phosphino amine, investigate potential effects such on average constants. Second, show...

Layered silicates have important applications as host materials, supports for catalysis, and zeolite precursors. However, their local structures are often challenging to establish due disorder of the sheet assemblies. We present a new protocol that combines long- short-range structural constraints from diffraction solid-state NMR techniques, respectively, determine molecular structure layered in presence various extents stacking disorder. Solid-state 29Si data largely insensitive incomplete...