Polycyclic Tetramate Macrolactams (PoTeMs) are a family of structurally complex natural products with significant bioactivities. Most of the widespread biosynthetic gene clusters (BGCs) of PoTeMs in bacteria remain silent under normal fermentation conditions. Herein, we report the construction of an efficient chassis (306A) to facilitate the heterologous studies of PoTeM BGCs, which reveals a biosynthetic logic for sequential C14 modifications of PoTeMs through characterizing a PoTeM gene cluster ( fla) from marine-derived Streptomyces falvogriseus SCSIO 40032. The C14 hydroxylation was mediated by flavin-dependent oxidoreductase FlaB1 when catalyzing the crucial C6—C13 cyclization, which was supported by feeding and 18O 2 labeling studies; the C14-OH groups in 5/5/6-type PoTeMs are subsequently converted to ketones by the cytochrome P450 enzyme FlaD. The FlaD homologs FtdF and SSHG_05717 were assayed to show similar functions as FlaD. Besides, the crystal structure of pactamide N ( 5) provides a critical reference for determining the absolute configuration of 5/5/6-type PoTeMs lacking C14 modifications. This study not only affords an efficient chassis for studying silent PoTeM BGCs, but also provides insights into the biosynthetic logic for C14 oxidative modifications of predominant 5/5- and 5/5/6-type PoTeMs.
Herein, we report a rare example of three-component net-oxidative sulfonylation of a SO 2 surrogate with an oxidatively activated radical precursor under mild and metal- and external-oxidant-free conditions. The mildness and sustainability of the reaction are enabled by photoelectrocatalysis, and 3-aza-1, 5-dienes, organotrifluoroborates and 1, 4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO) undergo sulfonylative cyclization to afford sulfono 4-pyrrolin-2-ones in an atom-economical manner with a broad substrate scope and good functional-group tolerance. The protocol is amenable to the late-stage diversification of complex molecular architectures as well as the gram-scale synthesis. Sunlight could be used as the light source, and the reaction could be conducted in an all-solar mode using a commercially available photovoltaic panel to generate electricity in situ. Mechanistic studies reveal that the in situ generated 1, 4-diazabicyclo[2.2.2]octane (DABCO), which was generally innocent in previous reactions, functions as an electron shuttle between the photocatalytic cycle and the reactants.
Herein, the temperature- and pressure-stimulated responsive behavior as well as crystal-glass phase transition of a new zero-dimensional hybrid manganese bromide [4-MTPP] 2[MnBr 4] [4-MTPP + = (4-methoxybenzyl)tris(phenyl)phosphonium)] were reported. Our experiment results demonstrate that [4-MTPP] 2[MnBr 4] shows typical green photoluminescence emission centered at 522.4 nm excited by UV light, with a high photoluminescence quantum yields value of 79.36% and a large lifetime of 368.6 µs, attributing to its direct bandgap electronic structure. Further, the photoluminescence emission of [4-MTPP] 2[MnBr 4] presents a monotonically blue shift with the increased temperature, originating from the decreased crystal field strength where the Mn 2+ stays owing to lattice thermal expansion effect. On the contrary, as the pressure increases, the photoluminescence emission of [4-MTPP] 2[MnBr 4] exhibits a progressive red shift, which can be attributed to the increased crystal field strength of Mn 2+ due to the effect of pressure-induced lattice shrinkage. Meanwhile, its quenched emission can be successfully restored when the pressure returns to the ambient pressure. In addition, [4-MTPP] 2[MnBr 4] crystals show a crystal-glass phase transition at the temperature of 74 °C. Intriguingly, the melt-quenched glass of [4-MTPP] 2[MnBr 4] exhibits green emission under UV light excitation with a large lifetime of 302.2 µs.
Imbalance in the levels of ascorbic acid (AA) can pose a risk to human health. Therefore, it’s essential to establish an accurate method for the detection of AA. In this work, a novel N-doped carbon composite (MnO x@NC) with dual enzyme-like activities to detect AA was prepared by calcination of Mn-MOF containing H 3TTPCA ligand. Interestingly, the •O 2 - that leads to its oxidase-like activity was not formed by dissolved oxygen, but came from the synergistic effect of lattice oxygen generated by calcination and the transformation of Mn II/Mn III/Mn IV, and the presence of H 2O 2 provided much •OH, which caused its peroxidase-like activity. Meanwhile, the residual N element came from H 3TTPCA ligand assisted the catalytic process. Accordingly, a dual-signal sensing platform and smartphone-assisted recognition for detection of AA was developed and a colorimetric sensor array was established to distinguish three antioxidants. This work also demonstrates considerable promise for the detection of AA in authentic pharmaceuticals.
For coordination-insertion olefin polymerization, the development of novel transition-metal catalysts has drawn extensive attention in this field. In this contribution, we designed a series of hemilabile α-diimine nickel catalysts bearing oxygen atom as neighboring group. The steric hindrance and oxygen atom number of these nickel complexes ( Ni1—Ni4) could be adjusted, which influenced ethylene (co)polymerization processes. The introduction of oxygen atoms could enhance the thermal stability during ethylene polymerization for Ni2 compared to the counterpart without oxygen atoms. And for the copolymerization process of ethylene with polar monomers, higher catalytic activity (1.4 × 10 6 g·mol -1·h -1) and polar monomer incorporation ratio (1.2 mol%) were achieved. However, Ni4 with four oxygen atoms in this work was not active in ethylene polymerization due to the interaction between the oxygen atom and nickel catalytic center. The hemilabile effect in this work presented an example to enhance the stability of the α-diimine nickel catalysts in olefin polymerization.
Pressure-treatment has been shown to be an effective means to enhance fluorescence of organic-inorganic halides though it is only limited to few examples. Here, we report the pressure-dependent structural evolution and emission enhancement upon compression treatment of a zero-dimensional halide, BTPP 2ZnBr 4 (BTPP = Benzyl triphenyl phosphonium). Compared to the uncompressed BTPP 2ZnBr 4 crystal, the pressure-treated sample shows a maximum 7-fold intensified fluorescence at ambient conditions while maintaining the wide-spectrum blue emission feature. This significantly boosted emission is attributed to the pressure-induced irreversible structural distortion which effectively reduces the non-radiative recombination. This work demonstrates the promising potential of pressure treatment in achieving bright organic-inorganic halide emitters and other molecular fluorescent materials.
Open-shell graphene fragments (OGFs) with non-benzenoid topologies are attracting increasing attention due to their potential applications in organic light-emitting diodes (OLEDs) and organic radical conductors. Herein, we report the synthesis of an air-stable fluorenyl radical derivative ( AR1) containing a seven-membered ring, achieving thermodynamic stabilization through the fusion of a naphthalene ring around its periphery and anthracene substituent. The half-life times ( τ 1/2) of AR1 in air-saturated solution is 71.9 h. The high stability was ascribed to kinetic blocking of reactive sites with high spin densities. The geometric and electronic structures of AR1 were systematically studied by combining various experimental methods and density functional theory (DFT) calculations, which include X-ray crystallographic analysis, electron spin resonance (ESR), cyclic voltammetry, and UV-vis-NIR measurements.
A design strategy towards stable fluorenyl radicals ( FRs) has been developed through introducing donor-π-radical (D-π-R) conjugation, facilitated by the linkage of amine N atoms and FR centers via phenyl or 9-anthryl moieties. Four FRs, with or without N atom containing protecting groups, were designed and synthesized for comparative analysis. X-ray crystallographic studies revealed the planar fluorenyl skeletons of CDP-FR and MA-FR, which exhibit significant dihedral angles relative to their protecting groups. Wiberg bond-order analysis and natural bond orbital analysis conducted on the C-C and C-N bond between the radical center and N atoms in all FRs clearly demonstrated the presence of D-π-R conjugation. Furthermore, time-dependent DFT calculations, based on frontier molecular orbital analysis, highlighted the contribution of D-π-R structures as donor-acceptor effect on the lowest energy absorptions of carbazole and diphenylamine substituted CDP-FR and DPAA-FR, which would promote charge transfer process and inhibit the photodegradation reaction. Consequently, beneficial from D-π-R conjugations, CDP-FR and DPAA-FR exhibited superior photostability compared to TP-FR and MA-FR. Our study offers a new strategy for the design and synthesis of persistent stable monoradicals.
The post-synthetic modification of two-dimensional sub-stoichiometric covalent organic frameworks (COFs) for gas separation, particularly for the efficient removal of CO 2 from CO 2/N 2 mixtures, is an area of growing interest yet remains relatively unexplored. In this study, we report the precise tuning of functional groups in sub-stoichiometric COFs to enhance CO 2 capture performance. A sub-stoichiometric COF with free aldehyde groups (HPCOF) was designed and synthesized, followed by covalent modification via ethylenediamine (EDA) grafting, yielding HPCOF-EDA. This post-modification strategy significantly increased CO 2 adsorption capacity (55.7 cm 3·g -1 at 298 K and 1 bar) and CO 2/N 2 selectivity (58), primarily attributed to the formation of additional N—H···O interactions. These findings demonstrate the potential of functional engineering to broaden the application prospects of sub-stoichiometric COFs in gas adsorption and separation technologies.
The programmability of DNA assembly allows for the creation of gold nanostructures with custom shapes and tailored optical properties, holding promise for applications including single-molecule sensing and imaging. While DNA origami provides addressable site information for structure construction, there have been few studies on encoding information onto gold nanoparticles (AuNPs) to guide the assembly of Au-DNA origami structures, especially for encoding extensive information onto large AuNPs ( e.g., 30 nm). In this work, we introduce a strategy that encodes extensive information onto versatile AuNPs ranging in size from 5 nm to 30 nm using a DNA origami template (parent origami). This encoded information serves to direct the positioning of the AuNPs within a regenerated DNA origami structure (daughter origami). Our findings demonstrate the successful assembly of AuNPs ranging from 5 nm to 30 nm on the same site of the daughter DNA origami as the parent DNA origami, with yields of up to 80%. This approach offers new possibilities for achieving precise control over AuNPs assembly and functionality.
Comprehensive Summary: The advancement of bioorthogonal cleavage reactions (BCRs) has expanded the scope of the bioorthogonal chemistry toolkit, leading to a diverse array of innovative biological applications. These include but are not limited to precise spatial and temporal activation of intracellular probes, prodrugs, proteins, glycans, and nucleic acids. Herein, we summarize recent efforts by our group to develop BCRs for manipulating functional molecules in living species to meet various needs, along with future perspectives in this exciting field.
How do you get into this specific field? Could you please share some experiences with our readers?
Chemists are good at both forming and breaking bonds. Back in 2013, while the field of bioorthogonal reactions was continuously thriving, most researchers focused on the "ligation" type of bioorthogonal reactions. Alternatively, I started to wonder whether we could develop the "bond-cleavage" type of bioorthogonal reactions? We reviewed the literature and found that this is indeed a field that is yet to be developed. I immediately encouraged my graduate students to develop such reactions while I began to look for potential applications for such new chemistry. We soon developed a series of bioorthogonal "cleavage" reactions that can be triggered by metals, small molecules, as well as photocatalysis. We then applied these reactions to activate proteins and other biomolecules, allowing the gain-of-function study of their properties inside living cells. Small molecule drugs can also be activated by these reactions within tumor bed, which has led to safer and more efficient anti-cancer drugs. Over the past decade, we have built a bioorthogonal decaging toolbox that is generally applicable to virtually any molecules of interest, and we are persistently working on broadening the spectrum of reaction types and their applications. This has created a new direction in bioorthogonal chemistry with broad utilities in life sciences and medicine.
How do you supervise your students?
I encourage students to think independently and collaborate widely. I would be delighted if some of their ideas could let me learn something. In addition to experimental training, I also pay great attention to cultivating students’ logical thinking, English writing, and presentation skills. For our regular weekly group meetings, two students will give in-depth presentations on their research projects, while all group members and I will provide constructive discussions and suggestions.
What is the most important personality for scientific research?
In my opinion, the most important personality traits for scientific research are curiosity, perseverance, and critical thinking.
What is your favorite journal(s)?
ACS Chemical Biology.
Could you please give us some advices on improving Chinese Journal of Chemistry?
Consider organizing special issues that focus on emerging areas of chemistry, which can attract high-quality submissions and increase the journal’s impact.
Comprehensive Summary: Deep-tissue physiological signals are critical for accurate disease diagnosis. Current clinical equipment, however, often falls short of enabling continuous, long-term monitoring. Wearable and implantable flexible electronics offer a promising avenue for addressing this limitation, allowing in vivo signal collection and paving the way for early diagnosis and personalized treatment. A major challenge lies in ensuring that these devices seamlessly integrate with the diverse physiological microenvironments throughout the human body. Mechanoadaptive bioelectronics is emerging as a key solution to optimize signal acquisition and device robustness. This review provides a comprehensive overview of the physiological characteristics of various organs and the types of signals they generate. Furthermore, it explores recent advancements in mechanoadaptive bioelectronics, systematically categorizes their strategies, and underscores their potential to revolutionize healthcare. Finally, we delve into the ongoing challenges in this field and highlight promising directions to advance the adaptability of bioelectronics further.
Key Scientists: In 2017, researchers developed an ionic skin with enhanced mechanical compatibility through strain-hardening properties. [1] Three years later, a neural interface platform called the adaptive self-healing electronic epineurium (A-SEE) was reported. [2] This platform minimized stress on neural tissue by dynamically relaxing stress. In 2021, an adaptive hydrogel hybrid probe was developed for long-term tracking of isolated neuroelectric activity, optogenetics, and behavioral studies of neural circuits. This probe also utilized hydration-induced softening to minimize the foreign body response. [3] In the same year, a shape-adaptive imager with a Kirigami design was proposed. [4] In the following year, a morphing electronic (MorphE) device was reported, which exhibited attractive viscoelasticity and minimal stress on the growing nerve during long-term implantation. [5] In 2023, a standardized tissue-electronic interface was developed, which can be implanted with minimally invasive cardiac procedures on a rapidly beating heart. [6] Recently, a needle-like microfiber based on biphasic liquid metal was created. This microfiber can reach the target site simply by puncturing and enable multifunctional sensing. [7] At about the same time, a device amalgamated with living and synthetic components was developed for studying and treating inflammatory skin disease. [8] This device enables real-time digital updates and potentially adaptive treatment of non-resolving inflammation, which is enlightening for the new generation of adaptive bioelectronics.