A one-pot O-alkylation mediated macrocyclization approach has been used for the synthesis of carbohydrate-based macrocyclic azobenzene. The synthesized macrocycle can be reversibly isomerized between E and Z isomers upon UV or visible irradiation with excellent photostability and thermal stability (t =51 days at 20 °C for the Z isomer). A chirality transfer from the chiral sugar unit to azobenzene was observed by circular dichroism (CD). DFT and TD-DFT calculations were performed to calculate the optimal geometry and the theoretical absorption and CD spectra. Comparison of the experimental CD spectra with the theoretical ones suggests that both E- and Z-macrocycles adopt preferentially P-helicity for the azobenzene moiety. Furthermore, the macrocycle showed gelation ability in cyclohexane and ethanol with multistimuli-responsive behavior upon exposure to environmental stimuli including thermal-, photo-, and mechanical responses. Moreover, these organogels display temperature-dependent helical inversion, which can be tuned by a repeated heating-cooling procedure.

Reversible photocontrol of glycosides and glycoconjugates structures is a very attractive approach to modulate, in a spatiotemporal way, the various properties and biological activities of carbohydrates. We have synthesized three new azobenzene‐derived glycomacrolactones from thioglycopyranosides. The synthesized cyclic glycoazobenzenes can be reversibly photoisomerized between E and Z isomers with high fatigue resistance. A 1H NMR spectroscopic study shows that E → Z isomerization of glycomacrocycles induces large conformational change of the macrocyclic structures, without changing sugar 4C1 chair conformation. The Z‐glycoazobenzenes can be thermally converted back to the E‐isomers. Interestingly, these 16 to 17‐membered Z‐glycomacrolactones display higher thermal stability than the reported macrocyclic azobenzenes, the half‐life varying from 37 to 72 days. The excellent photoswitching property and bistability of the synthesized glycoazobenzenes open a new opportunity for the convergent synthesis of diastereomers of glycomacrocycles. Furthermore, chiroptical properties have been observed for both E and Z glycomacrolactones. The geometry of different isomers of macrocycles has been optimized with DFT calculations. Theoretical CD spectra obtained by TD‐DFT suggest that the E and Z glycomacrocycles adopt preferentially (P) helical structure for the azobenzene moiety.

We demonstrate photoresponsive cholesteric liquid crystals (CLCs) doped with glycomacrocyclic azobenzene derivatives, which exhibit large conformational changes, providing dynamic control of helical superstructures in response to a light stimulus. An unprecedented shortening of the helical pitch length and the empowerment of helical twisting power up to 500% are observed upon trans (E) to cis (Z) photoisomerization. Light-driven dynamic helix twisting and untwisting behavior affords the first example of glycomacrocyclic 2 azobenzenes-based CLCs which can drive the mechanical movement of micro-objects. Two modes of rotations -two-directional or one-directional rotational motion (crankshaft mode)are realized. In particular, the latter mode based on the reversible cholesteric texture transition between homogeneous stripes and focal conics leads to the accumulation of the rotation angles achieving the amplified mechanical movements.

An intramolecular glycosylation approach has been successfully used to synthesize a series of photoswitchable glycomacrocycles with excellent α-stereoselectivity and interesting photochromic and chiroptical properties.

During an earthquake sequence, there are often multiple recurring landslides. Understanding the spatial distribution of the landslides triggered by the rst earthquake can help us predict the landslide susceptibility for subsequent shakes over a short term. This study used two landslide inventories from the Lombok earthquake sequence in Indonesia in 2018 to construct a short-term secondary disaster prediction model and an overall spatial prediction model using four machine learning algorithms. The average accuracy of the positive samples predicted by the prediction model was 7.1% lower than that of the short-term model. The highest accuracy of the overall prediction model was 14.9% higher, on average, and the area under the ROC curve (AUC) score was 8.1% higher, on average, but the corresponding probability thresholds were lower. The reason for this difference is that, in the short-term prediction model, since most of the landslides in the rst landslide inventory were prone to fail two or more times due to the effect of multiple earthquakes, the prediction results have a high positive rate. This feature of the short-term prediction model makes it suitable for landslide rescue guidance in a sequence of earthquakes. In contrast, the overall prediction model can better represent the spatial distribution of the earthquake-triggered landslides in the area.

A switchable carbohydrate‐embedded macrocyclic supramolecular gelator has been generated by a one‐pot O‐alkylation mediated macrocyclization approach. The synthesized azobenzene‐based glycomacrocycle can be reversibly isomerized between E and Z isomers upon light irradiation with excellent photostability and thermal stability (t1/2=51 days at 20 °C for the Z isomer). The macrocycle showed chirality transfer, multistimuli‐responsive organogel formation behavior upon exposure to external triggers, and helical inversion during the self‐assembly and gel formation. For more details, see the Communication by J. Xie et al. on page 14996 ff.

Photochromism, a reversible photo‐induced transformation of a molecule between two isomers having distinguishably different absorption spectra, has found increasing applications in materials science, chemistry, biology and pharmacology. In this review, we summarize our recent efforts on the development of photoswitchable carbohydrates and their conjugates. Synthesis, photophysical properties and potential applications of azobenzene‐functionalized glycomacrolactones and glycolipids, as well as multichromophoric sugar bearing diarylethene photochrome and dicyanomethylene‐4H‐pyran fluorophore will be discussed and compared.

SHAPE chemistry (selective 2'-hydroxyl acylation analyzed by primer extension) has been developed to specifically target flexible nucleotides (often unpaired nucleotides) independently to their purine or pyrimidine nature for RNA secondary structure determination. However, to the best of our knowledge, the structure of 2'-O-acylation products has never been confirmed by NMR or X-ray data. We have realized the acylation reactions between cNMP and NMIA under SHAPE chemistry conditions and identified the acylation products using standard NMR spectroscopy and LC-MS/MS experiments. For cAMP and cGMP, the major acylation product is the 2'-O-acylated compound (>99%). A trace amount of N-acylated cAMP has also been identified by LC-UV-MS. While for cCMP, the isolated acylation products are composed of 96% of 2'-O-acylated, 4% of N,O-diacylated, and trace amount of N-acylated compounds. In addition, the characterization of the major 2'-O-acylated compound by NMR showed slight differences in the conformation of the acylated sugar between the three cyclic nucleotides. This interesting result should be useful to explain some unexpected reactivity of the SHAPE chemistry.