The present study has deepened our molecular-level understanding of the oxidation mechanism of unsaturated lipids that are widely found in many biological systems.Reversible catalytic reactions operate under thermodynamic control, and thus, establishing a selective catalytic system poses a considerable challenge. Herein, we report a reversible transfer hydrocyanation protocol that exhibits high selectivity for the thermodynamically less favorable branched isomer. Selectivity is achieved by exploiting the lower barrier for C-CN oxidative addition and reductive elimination at benzylic positions in the absence of a cocatalytic Lewis acid. Through the design of a novel type of HCN donor, a practical, branched-selective, HCN-free transfer hydrocyanation was realized. The synthetically useful resolution of a mixture of branched and linear nitrile isomers was also demonstrated to underline the value of reversible and selective transfer reactions. In a broader context, this work demonstrates that high kinetic selectivity can be achieved in reversible transfer reactions, thus opening new horizons for their synthetic applications.The NH4I-triggered formal [4 + 2] annulation of α,β-unsaturated ketoxime acetates with N-acetyl enamides has been developed. The current protocol employs electron-rich enamides as C2 synthons and enables the efficient and straightforward construction of polysubstituted pyridines in moderate to good yields based on metal-free systems. The reaction tolerates a wide range of functional groups and represents an alternate route toward the synthesis of pyridine derivatives.The rotational dynamics of dirhodium supramolecular gears, formed with four 9-triptycene carboxylates cyclically arranged around a dirhodium core with variable axial ligands as originally designed by Shionoya et al., provide an excellent opportunity to evaluate the potential of computational methods and expand our understanding of the factors determining geared dynamics. Rotational dynamic rates in these structures depend on the nature of the axial ligand as shown by simulations over timescales that are not accessible experimentally. Molecular dynamics simulations gave information on the gearing mechanism, and the activation barriers to gearing were calculated using density functional theory. Steric demands imposed by the axial ligand were quantified using buried volume analysis. https://www.selleckchem.com/products/5-cholesten-3beta-ol-7-one.html We found that gearing takes place in all six dirhodium-gear complexes with different axial ligands and that rotational barriers depend on their steric size.Two-dimensional (2D) perovskites are emerging photovoltaic materials because of their highly tunable photophysical properties and improved environmental stability in comparison with 3D perovskites. Here, a thiophene-based bulky dication spacer, namely, 2,5-thiophenedimethylammonium (ThDMA), was developed and applicated in 2D Dion-Jacobson (DJ) perovskite. High-quality 2D DJ perovskite, (ThDMA)(MA)n-1PbnI3n+1 (nominal n = 5), with improved crystallinity, preferred vertical orientation, and enlarged spatially resolved carrier lifetime could be achieved by a one-step method using a mixed solvent of DMF/DMSO (v/v, 91). The optimized device exhibits a high efficiency of 15.75%, which is a record for aromatic spacer-based 2D DJ perovskite solar cells (PSCs). Moreover, the unencapsulated 2D DJ perovskite devices sustained over 95% of their original efficiency after storage in N2 for 1655 h. Importantly, both the light-soaking stability and thermal stability (T = 80 °C) of the 2D DJ perovksite devices are dramatically improved in comparison with their 3D counterparts. These results indicate that highly efficient and stable 2D DJ PSCs could be achieved by developing thiophene-based aromatic spacers as well as device engineering.The potent DNA-binding compound triaminotriazine-acridine conjugate (Z1) functions by targeting TT mismatches in CTG trinucleotide repeats that are responsible for causing neurological diseases such as myotonic dystrophy type 1, but its binding mechanism remains unclear. We solved a crystal structure of Z1 in a complex with DNA containing three consecutive CTG repeats with three TT mismatches. Crystallographic studies revealed that direct intercalation of two Z1 molecules at both ends of the CTG repeat induces thymine base flipping and DNA backbone deformation to form a four-way junction. The core of the complex unexpectedly adopts a U-shaped head-to-head topology to form a crossover of each chain at the junction site. The crossover junction is held together by two stacked GC pairs at the central core that rotate with respect to each other in an X-shape to form two nonplanar minor-groove-aligned G·C·G·C tetrads. Two stacked GC pairs on both sides of the center core are involved in the formation of pseudo-continuous duplex DNA. Four metal-mediated base pairs are observed between the N7 atoms of G and CoII, an interaction that strongly preserves the central junction site. Beyond revealing a new type of ligand-induced, four-way junction, these observations enhance our understanding of the specific supramolecular chemistry of Z1 that is essential for the formation of a noncanonical DNA superstructure. The structural features described here serve as a foundation for the design of new sequence-specific ligands targeting mismatches in the repeat-associated structures.The photocatalytic fuel cell (PFC) provides an elegant approach for the construction of a light-induced self-powered sensing platform. Nevertheless, the quantification of a target with a single output signal in an ordinary PFC-based sensor is easily affected by variation of the light intensity and other environmental factors. Herein we propose a ratiometric self-powered aptasensor for highly selective detection of 17β-estradiol (E2) based on a dual-channel PFC constructed with two photoanodes which could effectively avoid the fluctuation of the light intensity. Taking the advantage of the inhibited output performance of PFC by E2 which was captured by aptamer immobilized on the photoanodes, E2 was quantified via the ratio of output power density values from dual photoanodes. Under optimum conditions, the ratiometric self-powered sensing signal was linearly related to the logarithm of E2 concentration in the range of 1 to 500 nM, with a detection limit (3S/N) of 0.12 nM. Thus, a new type of self-powered aptasensor with high accuracy and specificity was successfully developed based on PFC in cooperation with a ratiometric assay and a spatial-resolution technique.