Solid-state NMR (ssNMR) is a versatile technique that can be used for the characterization of various materials, ranging from small molecules to biological samples, including membrane proteins. ssNMR can probe...

Reported here for the first time is the alkaline periodate oxidation of lignocelluloses for the selective isolation of cellulose nanocrystals (CNCs). With the high concentrations as a potassium salt at pH 10, periodate ions predominantly exist as dimeric orthoperiodate ions (H2I2O104−). With reduced oxidizing activity in alkaline solutions, dimeric orthoperiodate ions preferentially oxidized non‐ordered cellulose regions. The alkaline surroundings promoted the degradation of these oxidized cellulose chains by β‐alkoxy fragmentation and generated CNCs. The obtained CNCs were uniform in size and generally contained carboxy groups. Furthermore, the reaction solution could be reused after regeneration of the periodate with ozone gas. This method allows direct production of CNCs from diverse sources, in particular lignocellulosic raw materials including sawdust (European beech and Scots pine), flax, and kenaf, in addition to microcrystalline cellulose and pulp.

The available magnetic field strength for high resolution NMR in persistent superconducting magnets has recently improved from 23.5 to 28 Tesla, increasing the proton resonance frequency from 1 to 1.2 GHz. For magic-angle spinning (MAS) NMR, this is expected to improve resolution, provided the sample preparation results in homogeneous broadening. We compare two-dimensional (2D) proton detected MAS NMR spectra of four membrane proteins at 950 and 1200 MHz. We find a consistent improvement in resolution that scales superlinearly with the increase in magnetic field for three of the four examples. In 3D and 4D spectra, which are now routinely acquired, this improvement indicates the ability to resolve at least 2 and 2.5 times as many signals, respectively.

No periodate oxidation on chitin? For the first time, direct selective alkaline periodate oxidation of chitin led to the isolation of ordered domains as uniform anisotropic and zwitterionic ChNCs after simultaneous removal of non-ordered domains.

Reported here for the first time is the alkaline periodate oxidation of lignocelluloses for the selective isolation of cellulose nanocrystals (CNCs). With the high concentrations as ap otassium salt at pH 10, periodate ions predominantly exist as dimeric orthoperiodate ions (H 2 I 2 O 10 4À ). With reduced oxidizing activity in alkaline solutions,dimeric orthoperiodate ions preferentially oxidized non-ordered cellulose regions.The alkaline surroundings promoted the degradation of these oxidized cellulose chains by b-alkoxy fragmentation and generated CNCs.T he obtained CNCs were uniform in size and generally contained carboxyg roups.F urthermore,t he reaction solution could be reused after regeneration of the periodate with ozone gas.T his method allows direct production of CNCs from diverse sources,inparticular lignocellulosic raw materials including sawdust (European beech and Scots pine), flax, and kenaf,inaddition to microcrystalline cellulose and pulp.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/10.

Internuclear distance determination is the foundation for NMR-based structure calculation. However, high-precision distance measurement is a laborious process requiring lengthy data acquisitions due to the large set of multidimensional spectra needed at different mixing times. This prevents application to large or challenging molecular systems. Here, we present a new approach, transferred-rotational-echo double resonance (TREDOR), a heteronuclear transfer method in which we simultaneously detect both starting and transferred signals in a single spectrum. This co-acquisition is used to compensate for coherence decay, resulting in accurate and precise distance determination by a single parameter fit using a single spectrum recorded at an ideal mixing time. We showcase TREDOR with the microcrystalline SH3 protein using 3D spectra to resolve resonances. By combining the measured N–C and H–C distances, we calculate the structure of SH3, which converges to the correct fold, with a root-mean-square deviation of 2.1 Å compared to a reference X-ray structure. The TREDOR data used in the structure calculation were acquired in only 4 days on a 600 MHz instrument. This is achieved due to the more than 2-fold time saving afforded by co-acquisition of additional information and demonstrates TREDOR as a fast and straightforward method for determining structures via magic-angle spinning NMR.

A catalyst-free one-pot methodology that enables direct nitrogen interception of chitosan/chitin for imidazo[1,5-a]pyridines was developed. This strategy is featured by directly synthesizing important deuterated imidazo[1,5-a]pyridines and tridentate ligands. In particular,...