Latest ArticlesMechanochromophores based on bichromic molecular switches, such as bis-naphthopyanes, allow multimodal mechanochromic behavior beyond the typical binary response from single chromophores, which is important for distinguishing between multiple stress states through discrete changes in color. Spontaneously generated persistent and distinguishable multi-colors from activated bis-naphthopyanes remain challenging. And the versatility of bis-mechanophore design for advanced optical molecular systems and the fundamental insights into the corresponding mechano-reactivity are not enough. Here, we identify a dihydroanthracene bridged bis-naphthopyrans as a multimodal mechanochromophore in polymers. Bridging two pyrans with the sterically constrained dihydroanthracene is helpful to control the steric effect for the favorable formation of a distinctly appreciable bis-merocyanine (bis-MC) product. By varying the length of the polymer chains, the force delivered to the mechanophore is modulated, resulting in a gradient change in the relative distribution of two distinctly colored MC products and a multicolor mechanochromism. Mechanical activation of this bis-naphthopyanes proceeds via a mechanistically distinct pathway compared to the photochemical process. In addition, the bulk films can also achieve pronounced color changes when subjected to mechanical force. This study thus further expands the molecular diversity of mechanochromophores and tune the multimodal switch properties of bis-naphthopyrans based polymers.
Azulene is a promising building block for creating innovative polycyclic aromatic hydrocarbons. This study involved the construction of three nonalternant isomers of pentacene by fusing two azulene units, named Az-PH1/2/3. Az-PH1 was initially developed through the rhodium(II)-catalyzed cyclization of bis(N-tosylhydrazone)s. Intriguingly, Az-PH1 was also unexpectedly obtained during a nickel(0)-catalyzed one-step tandem reaction. We investigated the optical and electrochemical properties, aromaticity, and photo-oxidative stability of Az-PH1, comparing it with the well-known pentacene using density functional theory, electrochemical, and photophysical tests. Our results showed that the azulene-fusing strategy resulted in a molecule with narrow optical bandgaps (2.046 eV) and a long half-life time under ambient air conditions.
Covalent organic polymer (COP) thin film-based memristors have generated intensive research interest, but the studies are still in their infancy. Herein, by controlling the content of hydroxyl groups in the aldehyde monomer, Py-COP thin films with different electronic push-pull effects were fabricated bearing distinct memory performances, where the films were prepared by the solid-liquid interface method on the ITO substrates and further fabricated as memory devices with ITO/Py-COPs/Ag architectures. The Py-COP-1-based memory device only exhibited binary memory behavior with an ON/OFF ratio of 1:101.87. In contrast, the device based on Py-COP-2 demonstrated ternary memory behavior with an ON/OFF ratio of 1:100.6: 103.1 and a ternary yield of 55%. The ternary memory mechanism of the ITO/Py-COP-2/Ag memory device is most likely due to the combination of the trapping of charge carriers and conductive filaments. Interestingly, the Py-COPs-based devices can successfully emulate the synaptic potentiation/depression behavior, clarifying the programmability of these devices in neuromorphic systems. These results suggest that the electronic properties of COPs can be precisely tuned at the molecular level, which provides a promising route for designing multi-level memory devices.
Microcystins (MCs), a family of cyclic heptapeptide cyanotoxins, exists in aquatic environment where cyanobacterial bloom happens, which will accumulate in aquatic organisms and transfer through the food chain to higher trophic levels, posing a health risk to both animals and human bodies. Among various MCs, Microcystin-LR (MC-LR) is worthiest studied for its strong toxicity, ubiquity and widespread. Here in this work, iminodiacetic acid (IDA) decorated magnetic mesoporous silica (mSiO2) nanocomposites (Fe3O4@mSiO2-IDA) were facilely synthesized which possessed the merits of large surface area (188.21 m2/g), accessible porosity (2.66 nm), excellent hydrophilicity and rapid responsiveness to magnetic field. Then the composites were successfully employed to the removal process of Microcystin-LR in real water samples followed by Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis, achieving the removal efficiency above 92.5% even after ten recycles of the composites. It provided a potential method for removing MC-LR in aqueous environment with high effectiveness, lower costs and less secondary contamination.
The virtual cocrystal screening approach based on molecular electrostatic potential surface (MEPS) maps is a fast and feasible computational method to estimate the probability of cocrystal formation by calculating the difference in the interaction site pairing energies of monomers and that of their assemblies prior to experimental screening. In this paper, we report 12 cocrystal forms of temozolomide with mono-, di-, and trihydroxy benzoic acids, namely, 3-hydroxy-, 2,4-dihydroxy-, 2,5-dihydroxy-, 2,6-dihydroxy-, 3,4-dihydroxy-, and 3,4,5-trihydroxy-benzoic acids, as well as benzoic acid, as pharmaceutical coformers for the first time. 10 single crystals out of the 12 cocrystal forms were obtained and unequivocally determined by single-crystal X-ray diffraction, which clarified spatial arrangements, molecular conformations, and supramolecular synthons. MEPS further gains some insights into the sites of hydrogen bonding interactions for exploring combination patterns in these assemblies. Modulated stability of TMZ was successfully achieved by cocrystallization with these acids.
As the most common pathological type of nephrotic syndrome, membranous nephropathy (MN) presents diversity in progression trends, facing severe complications. The precise discrimination of MN from healthy people, other types of nephrotic syndrome or those with therapeutic remission has always been huge challenge in clinics, not to mention comprehensive individualized monitoring relied on minimally invasive molecular detection means. Herein, we construct a functionalized pore architecture to couple with machine learning to aid all-round peptidome enrichment and data profiling from hundreds of human serum samples, and finally establish a set of defined peptide panel consisting of 12 specific feature signals. In addition to the realization of above-mentioned precise discrimination with more than 97% of sensitivity, 88% of accuracy and f1 score, the simultaneously comprehensive individualized monitoring for MN can also be achieved, including conventionally screening diagnosis, congeneric distinction and prognostic evaluation. This work greatly advances the development of peptidome data-driven individualized monitoring means for complex diseases and undoubtedly inspire more devotion into molecular detection field.
Quinoidal π-conjugated structures, a kind of fundamental subunits for organic π-systems, may produce some intriguing optical, electronic and magnetic properties of polycyclic hydrocarbons (PHs). Herein, we report two thienothiophene-centered ladder-type polycyclic molecules (1 and 2), which possess one quinoidal thienothiophene moiety and two para-quinodimethane (p-QDM) subunits, respectively. As theoretically and experimentally studied, while 1 is a fully closed-shell molecule, 2 owns an open-shell structure along with partial contribution of tetraradical state that is induced by the resonance of p-QDM. Moreover, although 2 has a larger π-conjugated skeleton and open-shell electronic state, it exhibits larger bandgap and blue-shifted absorption. On the other hand, the reversible oxidation activity of 1 enables the preparation of its dication, and the studies on its single-crystal and aromatic structures demonstrate that its two positive charges are delocalized onto the oxygen atoms, thus achieving fully π-extended structure and near-infrared absorption. This study not only gains insight into quinoidal π-subunits, but also provides an important basis for the development of antiaromatic and open-shell π-electron materials.
Electrocatalytic synthesis of ammonia as an environment-friendly and sustainable development method has received widespread attention in recent years. Two-dimensional (2D) materials are a promising catalyst for ammonia synthesis due to their large surface area. In this work, we have constructed a series of 2D metal borides (MBenes) with transition metal (TM) defects (TMd-MBenes) and comprehensively calculated the reactivity of electrocatalytic synthesis of ammonia-based on density functional theory. The results have demonstrated that the TMd-MBenes can effectively activate nitrogen oxide (NO) and nitrogen (N2) molecules thermodynamically. Particularly interesting, the co-chemisorption of O atoms, dissociated from NO, can facilitate the spilled of the inert N2 molecules into single N atoms, which can further hydrogenate into ammonia easily with an ultralow limiting potential of 0.59 V on TMd-MnB. Our research has not only provided clues for catalyst design for experimental study but also paved the way for the industrial application of electrocatalytic ammonia synthesis.
Photosensitization related to energy/electron transfer process is of great importance to natural photosynthesis. Herein, we proposed a promising strategy to improve the sensitizing ability of the typical photoactive MOFs (UiO-Ir) by engineering its metal coordination center with NBI (1, 8-naphthalenebenzimidizole) chromophore. The resulting MOFs (UiO-Ir-NBI) exhibited a strong sensitizing ability for significantly boosting photosynthesis. Impressively, the catalytic yield of 2-chloroethyl ethyl sulfoxide with UiO-Ir-NBI can reach 99%, over 6 times higher than that with UiO-Ir (16.4%). Moreover, UiO-Ir-NBI exhibited an excellent catalytic stability and a broad substrate tolerance, highlighting its great application prospect. Systematic investigations revealed that the strong visible light absorption, long excited state lifetime and efficient electron-hole separation of UiO-Ir-NBI greatly contributed to harvesting visible light and facilitating interface electron/energy transfer for efficient solar energy utilization. This work provides a new horizon to boost photosythesis of MOFs by engineering their metal sensitizing centers at a molecular level.
We reported the characterization of a novel brassicicene diterpene biosynthetic gene cluster, which contains a unique α-ketoglutarate-dependent dioxygenase (αKGD) enzyme, AbnI. Our findings revealed that AbnI demonstrates remarkable substrate promiscuity and is capable of activating multiple sites on both 5–8–5 and 5–9–5 brassicicene skeletons, resulting in skeleton modifications and an unexpected ring system rearrangement. These results suggested the potential utility of AbnI as an enzymatic tool for terpene CH functionalization. In addition, the catalytic mechanism of AbnI and its potential ecological implications were discussed.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
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
