Search

Imidazopyridines, benzimidazoles and their derivatives are important heterocyclic substances with a wide range of future applications in the field of fluorescent sensors due to their excellent solid-state luminescence properties, long fluorescence lifetimes, and large Stokes shifts. Two 3-phenylimidazo[1,5-a]pyridines and two 2-phenyl-1H-benzo[d]imidazoles were synthesized and spectroscopically characterized by NMR spectroscopy and fluorescence spectroscopy analysis. The molecular structures and crystal stacking properties of three types of compounds, namely, imidazo[1,2-a]pyridine, imidazo[1,5-a]pyridine and benzimidazole, have been investigated by single-crystal X-ray diffraction analysis, and the results show that the different positions of the N atoms affect the stacking of the crystals, whereas the molecules are connected mostly through intermolecular π–π stacking and C–H⋯N and C–H⋯π interactions. Tight π-stacking contacts lead to a decrease in the fluorescence quantum yield of the molecules. Also, the shortened distance between imidazolepyridine or benzimidazole units and the strong aromatic interactions from polar substituents lead to solid-state fluorescence quenching. With the help of Hirshfeld surface analysis and electrostatic potential analysis, the roles of various noncovalent forces including hydrogen bonding, π-stacking, and C–H⋯π interactions in the formation of solid-state molecules are elucidated. The redshift of the emission spectra in solution with increasing solvent polarity and the apparent separation of the electron cloud densities between the HOMO and LUMO orbitals suggest that all seven compounds are typical intramolecular charge transfer (ICT) molecules. The HOMO–LUMO energy gap results are consistent with the fluorescence emission behavior of the compounds in solution and solid states. [ABSTRACT FROM AUTHOR]

An efficient I2 (10 mmol %)/H2O2 mediated oxidative formal [4+1] cyclization of 2‐pyridinemethylamine or o‐phenylenediamine (2‐aminobenzenethiol) with benzaldehyde via C−N bond formation has been developed. This strategy provides a straightforward approach to imidazo[1,5‐a]pyridines, iodo‐substituted imidazo[1,5‐a]pyridines and benzimidazole (benzothiazole) derivatives in yields ranging from 60 % to 98 %, respectively. Several heterocyclic products exhibit promising blue luminous performance with satisfactory fluorescence quantum yields of up to 64 %, large Stokes shifts, and a longer lifetime (7.35 ns). The band gap energies obtained from DFT are also consistent with the absorption spectra. [ABSTRACT FROM AUTHOR]

Cp2Fe-mediated electrochemical synthesis of a diverse array of phosphorylated azaspiro[4.5]di/trienones has been developed, which demonstrated broad substrate scope and good diastereoselectivity. It represents the first example of electrochemical synthesis of phosphorylated azaspiro[4.5]di/trienones, circumventing the need for external oxidants and high temperatures. Moreover, a plausible mechanism including radical-initiated dearomative cyclization driven by ferrocenium cations has been provided, which was supported by the related mechanistic study. [ABSTRACT FROM AUTHOR]

Unlike traditional organic methods, electrosynthesis has emerged as an environmentally friendly and sustainable approach to generate a series of functionalized compounds. In this process, the traceless electron serves as the redox agent, eliminating the need for stoichiometric oxidants or reductants. In contrast to direct electrolysis, redox‐mediated electrolysis has the ability to overcome kinetic inhibitions and achieve diverse selectivity under mild conditions. This has garnered increasing attention from the synthetic community, especially in the past few years. This review will focus on Cp2Fe‐mediated electrosynthesis of diversified functionalized compounds through C−N, C−C, C−P and C−O bond formation over the past decade. [ABSTRACT FROM AUTHOR]

Drawing inspiration from the initiating amino acid modification in biosynthetic peptides, we have successfully demonstrated a biomimetic mechanism for N-to-C terminal extension in prebiotic peptide synthesis. This achievement was accomplished by using acetylated amino acid amides as the N-terminal substrate for peptide synthesis and amino acid amides as the C-terminal extension, with the reaction carried out in a dry-wet cycle at 80 °C without requiring any activators. This provides a plausible pathway for the formation of prebiotic peptides. [ABSTRACT FROM AUTHOR]

As the cornerstone mission of the fourth phase of the Chinese Lunar Exploration Program, Chang'E-7 (CE-7) was officially approved, and implementation started in 2022, including a main probe and a communication relay satellite. The main probe, consisting of an orbiter, a lander, a rover and a mini-flying probe, is scheduled to be launched in 2026. The lander will land on Shackleton crater's illuminated rim near the lunar south pole, along with the rover and mini-flying probe. The relay satellite (named Queqiao-2) will be launched in February 2024 as an independent mission to support relay communication during scientific exploration undertaken by Chang'E-4, the upcoming Chang'E-6 in 2024 and subsequent lunar missions. The CE-7 mission is mainly aimed at scientific and resource exploration of the lunar south pole. We present CE-7's scientific objectives, the scientific payloads configuration and the main functions for each scientific payload with its key technical specifications. [ABSTRACT FROM AUTHOR]

Synthesis of valuable compounds directly from small and simple molecules is an area of great interest in chemical research. However, the preparation of most organophosphorus compounds from white phosphorus currently relies on inefficient, stepwise procedures that result in significant environmental pollution and poor atom economy. We herein describe a novel and high-yielding route to generate various phosphorothioates with diverse substituents from white phosphorus, disulfides, and alcohols in a single reaction step. This innovative three-component coupling reaction utilizes basic industrial raw materials and offers several advantages, including operational simplicity, mild reaction conditions, a broad substrate scope, and high product selectivity. [ABSTRACT FROM AUTHOR]

Correction for 'Metal-free visible-light-induced phosphorylation of unactivated alkyl iodides with white phosphorus as the P-atom source' by Fushan Chen et al., Green Chem., 2023, 25, 6629–6634, https://doi.org/10.1039/D3GC01579C. [ABSTRACT FROM AUTHOR]

A comprehensive and systematic view and solution to the protection and renewal of traditional villages can help actively promote and implement the strategy of rural revitalization. This paper constructs a village protection and renewal evaluation system based on the maximum information entropy model, utilizes the entropy weight method to build the index weight evaluation matrix, and introduces the confidence factor to correct the index weights, realizing the combination of the system. Then, based on the linear weighting method to carry out a comprehensive assessment of village protection and renewal development, and based on the assessment results to formulate a personalized village protection and renewal strategy, and the feasibility analysis of the strategy with the village of T city. The results show that village protection and renewal in T city villages generally indicate an upward trend from 2016 to 2023, and the comprehensive evaluation index reached a peak of 0.3227 in 2023. In the case study, the linear regression equations fitted to the scattering points of the uptown residential area villages and the entire T city villages’ axes intersect with a difference in slopes of 14.5123. The angle of the regression line continues to increase in comparison with 2016, indicating that the role of traditional village protection planning is significant. Village protection planning plays an important role in verifying the effectiveness of the formulated village protection and renewal strategy, which can promote the development of village regional characteristics for the good.