Higher isotropic resolution in solids is essential for accurate assignment of the chemical shifts in multisite chemical and biological systems; consequently, the pursuit of solution-like resolution in solid samples remains an ongoing challenge. MAS provides the effective averaging of the anisotropic interactions to the first-order while the higher order interactions, such as residual dipolar splitting

Nuclear magnetic resonance (NMR) spectroscopy is an important technique for molecular structure determination but is inherently limited by its low sensitivity. Recently, the Dynamic nuclear polarization (DNP) technique has emerged as a solution to overcome the intrinsic low sensitivity of NMR spectroscopy by transferring polarization from the unpaired electron spins to nuclear spins under microwave

We report utilization of transverse relaxation rate (R2) of 17O (I = 5/2) satellite transitions (STs) as a probe of molecular dynamics in solids. A simple theoretical model using spectral density functions is proposed to describe the general R2 behaviors of half-integer quadrupolar nuclei in solids in the presence of molecular motion (or chemical exchange). Experimental 17O R2 data recorded for both

Chitin is the most important nitrogen-containing polysaccharide found on Earth. This polysaccharide is a polymer of an N-acetylglucosamine and it is a crucial structural component of fungal cell walls and crustaceans. Magic-angle spinning solid-state NMR is emerging as a powerful analytical approach to study polysaccharides in the context of intact cell walls and whole cells. The presence of an acetamido

Probing the fast dynamics of surface sites using NMR spectroscopy is highly challenging owing to the sites' high dilution and the difficulties often associated with isotopic enrichment. Intra-CH21H–1H dipolar couplings are ideal probes of motions given that they only involve 1H's and the tensor has a well-defined size and orientation. We introduce a frequency-selective variant of the double-quantum

A cross-polarization 2H–1H isotope correlation spectroscopy (CP-iCOSY) approach is presented for characterizing a deuterated amino acid, pharmaceutical compound and a solid formulation. This can be achieved by isotopic enrichment in conjunction with high magnetic field (28.2 T) and fast magic-angle spinning (MAS), enabling the rapid detection of 2H NMR spectra in a few seconds to minutes. Specifically

The naturally abundant 14N isotope (>99 %) is sparingly employed for characterization in solid-state nuclear magnetic resonance (NMR) despite the importance of nitrogen atoms in shaping molecular structures and properties. This inhibition can be attributed to large quadrupolar couplings (∼several MHz), resulting in more involved spin methodologies for 14N nuclei. Experimentally, spin-½ nuclei are utilized

Exciting developments in new experimental methods for multidimensional solid-state NMR spectroscopy have recently been achieved using optimal-control theory. These results, in turn, have triggered the development of new pulse sequences based on traditional analytical theories. This trend article summarises the key steps leading to these advancements. It also describes additional applications of optimal

Cellulose–lignin blends are proposed as alternative precursors for carbon fiber (CF) production, offering a potential sustainable and cost-effective alternative to the expensive fossil-based polymers currently used. The characteristics of the precursor fibers including their crystallinity, the incorporated chemical structures and the distribution of the biopolymers have a significant influence on their

17O NMR methods are emerging as a powerful tool for determination of structure and dynamics in materials and biological solids. We present experimental and theoretical frameworks for measurements of 17O NMR relaxation times in static solids focusing on the excitation of the central transition of the 17O spin 5/2 system. We employ 17O-enriched NaNO3 as a model compound, in which the nitrate oxygen atoms

People with the genetic disease cystic fibrosis (CF) often have chronic airway infections and produce airway secretions called sputum. A better understanding of sputum composition is desired in order to track changes in response to CF therapeutics and to improve laboratory models for the study of CF airway infections. The glycosylated protein mucin is a primary component. Along with extracellular DNA

Among the many natural biomaterials for which information on atomic-level structure and reorientational motion can offer essential clues to function, insoluble multi-component composites with limited degrees of order are among the most challenging to study. Despite its limited sensitivity, solid-state NMR (ssNMR) is often the technique of choice to ferret out these details in carbon- and nitrogen-rich

The molecular structure of hydrochars produced from 13C-enriched glucose under various conditions has been elucidated based on advanced one- and two-dimensional (2D) 1H-13C and 13C–13C solid-state nuclear magnetic resonance (NMR) with spectral editing. Regardless of synthesis conditions, hydrochars consist mostly of oxygen-substituted arene rings (including diphenols) and furans connected by alkyl

Solid-state NMR has great potential for investigating molecular structure, dynamics, and organization of the stratum corneum, the outer 10–20 μm of the skin, but is hampered by the unfeasibility of isotope labelling as generally required to reach sufficient signal-to-noise ratio for the more informative multidimensional NMR techniques. In this preliminary study of pig stratum corneum at 35 °C and water-free

We present a high-resolution magic-angle spinning (MAS) solid-state NMR (ssNMR) study to characterize nontuberculous mycobacteria (NTM). We studied two different NTM strains, Mycobacterium smegmatis, a model, non-pathogenic strain, and Mycobacterium abscessus, an emerging and important human pathogen. Hydrated NTM samples were studied at natural abundance without isotope-labelling, as whole-cells versus

Through-space heteronuclear correlation experiments under magic-angle spinning (MAS) conditions can provide unique insights into inter-atomic proximities. In particular, it has been shown that experiments based on two consecutive coherence transfers, 1H → I → 1H, like D-HMQC (dipolar-mediated heteronuclear multiple-quantum correlation), are usually more sensitive for the indirect detection via protons

This study builds upon our prior researches and seeks to investigate and clarify the influences of various characteristics of hydrogen bonds (H-bonds) and charge transfer (CT) interactions, which were detected within the inhibitor binding pockets (labeled as the QM models I–IV) of MraY–capuramycin, MraY–carbacaprazamycin, MraY–3′-hydroxymureidomycin A, and MraY–muraymycin D2 complexes by QTAIM and

In this work, we elucidated the structural organization of stimuli-responsive peptide-polydiacetylene (PDA) conjugates that can self-assemble as 1D nanostructures under neutral aqueous conditions. The amino acid sequences bear positively or negatively charged domains at the periphery of the peptide segments to promote solubility in water while also driving assembly of the individual and combined components

Planewave-corrected methods have proven effective for accurately modeling nuclear magnetic resonance (NMR) parameters in crystalline systems. Recent work extended the application of planewave-corrected calculations beyond the second row, predicting EFG tensor parameters for Cl using a simple molecular correction to projector augmented-wave (PAW) density functional theory (DFT). Here we extend this

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While syringyl units are the most abundant monolignols in hardwood lignin, their phenolic (i.e. hydroxyl) end group concentration has not been measured. In two uniformly C-enriched young hardwoods, from beech and oak, the syringyl units were quantitatively investigated by advanced solid-state C NMR. Small signals of OH-terminated syringyl units were resolved in spectrally edited two-dimensional C–C

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