Latest ArticlesIn this contribution, we describe the preparation and recognition characteristics of a novel tetrapodal benzene cage (1). The cage can express a wide recognition range without losing selectivity for the object of appropriate size and functional groups. The key to obtaining the desired structural isomer of 1 is the synthesis and isolation of the o-bis(bromomethyl)benzene precursor (5). Three distinct guests, F− (extremely small size), D-lactate (appropriate size) and L-Asp (branched shape), were selected as examples to demonstrate the recognition characteristics of 1. By NMR titration studies, they all expressed good binding affinity (K > 105 L/mol) in competitive medium (10% DMSO/THF), indicating that 1 has a wide recognition scope. The highest binding constant was observed for D-lactate, revealing that 1 has good selectivity for D-lactate versus F− and L-Asp. Moreover, the NMR titration study of F− in DMSO indicates 1 can achieve different binding modes (1:1 and 2:1 guest-host) for small-sized guests, which allows for the further development of binary binding properties and thereafter applications in the field of catalysis.
New fabrication method of nanostructures is of great importance for the applications of nanoscience and nanotechnology. This review summarizes cucurbit[n]uril (CB[n])-based nanostructure fabrication and modification approaches. These strategies include the use of CB[n]s as building blocks and supramolecular crosslinkers to fabricate nanostructures, to surface modify nanostructures, and as gatekeepers to control the release of encapsulated cargo. These nanostructures are used for drug delivery, bioimaging, chemical sensing, catalysis and other applications. CB[n]s often play a vital role in the fabrication of these nanostructures, and the realization of the applications.
Organic lasers with broad emission bands in near-infrared (NIR) region are crucial for their applications in laser communication, night-vision as well as bioimaging owing to the abundance of selectable lasing wavelengths. However, for most organic gain materials, gain regions are limited in a small wavelength range because of the fixed energy level systems. Herein, we design a strategy to realize NIR organic lasers with broad emission bands based on tunable energy level systems induced by cascaded excited-state intramolecular proton transfer (ESIPT). A novel gain material named DHNN was developed, which can undergo a cascaded double-ESIPT process supporting four-level and six-level systems simultaneously. By doping DHNN into polystyrene microspheres, NIR lasers with tunable emission bands can be achieved based on the careful modulation of microcavities. Finally, organic lasers with an ultra-broad emission band ranging from 700 nm to 900 nm was successfully achieved by harnessing four-level and six-level systems simultaneously.
The extraction of radioactive minor actinides (An(Ⅲ)) from lanthanides (Ln(Ⅲ)) is an extremely important step in nuclear waste reprocessing. Designing ligands with high-performance actinide-selectivity remains an essential task. Recent works have reported that some polyazole based ligands exhibit good An(Ⅲ)/Ln(Ⅲ) separation performance. Herein, we first evaluated the effects of different polyazole side chains on the Am(Ⅲ)/Eu(Ⅲ) selectivity by exploring three pyridine-derived polyazole ligands L1, L2 and L3 with 1,2,4-triazole, 1,2,3-triazole, and pyrazole side chains, respectively, using scalar relativistic theoretical methods. The coordination structures, bonding properties and thermodynamic behaviors of AmL(NO3)3 and EuL(NO3)3 complexes were investigated, which clarifies that the side chains do affect the electronic structure of ligand and its selectivity for Am(Ⅲ)/Eu(Ⅲ) ions. Moreover, L1 with 1,2,4-triazole side chains exhibited the highest selectivity for Am(Ⅲ) over Eu(Ⅲ) while the lowest complexation ability for metal ions among the three pyridine-derived polyazole ligands. Subsequently, we designed a new ligand L4 containing 1,2,4-triazole side chains and a preorganized phenanthroline backbone. Theoretically, such a new ligand was verified to show stronger complexation ability and higher selectivity for Am(Ⅲ)/Eu(Ⅲ) ions than L1. This work clarifies the complexation nature of polyazole based ligands with Am(Ⅲ)/Eu(Ⅲ) ions and provides design strategies for highly efficient polyazole based ligands for An(Ⅲ)/Ln(Ⅲ) separation.
A photochromic molecular rotor based on stiff-stilbene (SSB-FMR) was handily prepared through coupled reaction, and further self-assembled with cucurbit[8]uril (CB[8]) to form a 2:2 quaternary supramolecular complex (SSB-FMR/CB[8]). Significantly, the intervention of CB[8] on SSB-FMR achieved dual functions that assembly-induced emission enhancement and assembly-induced improvement of photoisomerized performance (especially reversibility) of stiff-stilbene molecular photoswitch. The supramolecular strategy further facilitated the assembly as a photoresponsive fluorescence switch with outstanding fatigue resistance, which was expediently applied in high-security-level QR code anti-counterfeiting and controllable lysosome targeted imaging. The study unprecedentedly provides a supramolecular method for highly efficiently improving photoisomerized performance especially reversibility of molecular photoswitches based on stiff-stilbene, and is of vital significance for the construction of intelligent materials with excellent capability.
The self-assembled structures of H3BDA molecule with multiple meta-dicarboxylic groups and their stimulus responses to the guest molecules (COR and T4PT) are thoroughly investigated by scanning tunneling microscopy (STM). STM observations display that two kinds of nanostructures are fabricated by H3BDA molecules through intermolecular hydrogen bonds, in which a linear structure is formed at a higher concentration and a flower-like structure is obtained at a lower concentration. After the addition of COR and T4PT, H3BDA appears different responsiveness resulting in different co-assembled structures, respectively. The linear structure is regulated into a flower-like structure by COR and COR molecules are trapped in the cavities. When the pyridine derivative (T4PT) is introduced, a new bicomponent porous structure emerges via the hydrogen bond formed between the carboxyl group and the pyridine. Furthermore, the deposition of additional COR to the H3BDA/T4PT system results in the breakdown of the porous structure and the generation of H3BDA/COR host–guest system. Combined with density functional theory (DFT) calculations and molecular dynamics (MD) simulations, the transformation phenomenon of bi-component nanostructure induced by guest molecules is formulated. The results are expected to understand the modification effect of guest molecules on the host network, which is of great significance for the design and construction of multi-component nanostructures and crystal engineering.
Heterocycle-braced cyclic peptides have demonstrated enhanced metabolic stability, increased potency and selectivity. Here, we present a rapid synthesis method for constructing Trp(C7)-alkene(E)-crosslinked cyclic peptides with potent anti-proliferative activities against cancer cells, through C-H alkenylation and macrolactamization. This report addresses critical challenges associated with the installation and removal of the directing group N-Piv, configuration selectivity of the olefin, and intramolecular cyclization. Notably, this method exhibits mild reaction conditions, traceless removal of the directing group, and high configuration selectivity.
The atom-economical C-F insertion chemistry is emerged as a promising technology for the synthesis of various fluorinated scaffolds, which have wide applications both in the academic and the industrial communities. The past three years have witnessed rapid developments in this field. This highlight provides an overview on the evolution according to the fluorinating agents used.
The dynamic kinetic asymmetric transformation of racemic propargylic ammonium salts with prochiral aldimine esters through a stereodivergent propargylation is catalyzed by dual nickel and copper catalysis. Thus, a diverse range of optically active α-quaternary amino esters were produced via CN bond cleavage with high reaction efficiency and stereoselectivity (up to > 99% ee). By selection of the appropriate pairwise combination of catalyst configurational isomers, all four possible stereoisomers of the corresponding propargylation products are obtained in high yields with excellent regio-, diastereo-, and enantioselectivities.
This study presents an unexpected finding that the cis isomer of β-thio-Asp exhibits higher ligation activity than the trans isomer. This discovery sheds light on the intricate nature of native chemical ligation and highlights the importance of factors beyond the steric effects of the side chain in modulating ligation activity.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62662699(Operation and Technical Support)
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
