L-Hexoses are key components of many biologically relevant natural products and pharmaceuticals. As rare sugars, L-hexoses are not readily obtained from natural sources. Access to L-hexose building blocks from commercially available and inexpensive D-sugars is highly desirable from the viewpoints of organic synthesis and drug discovery. As demonstrated by the convenient preparation of L-glucosyl, L-galactosyl, and L-mannosyl fluorides from readily available β-D-C-glucosyl, β-D-C-mannosyl, and β-D-C-galactosyl derivatives, we describe a novel and efficient approach to the demanding L-glycosyl fluorides. The transformation features the installation of anomeric hydroxymethyl group under mild conditions and head-to-tail inversion of sugar rings through radical decarboxylative fluorination of uronic acids. The power of this protocol is highlighted by the first assembly of a pentasaccharide repeating unit of Pseudomonas ATCC 31554 extracellular polysaccharide (S-88). This synthesis relies on the efficient extension of sugar chain at the sterically hindered hydroxy group and the facile introduction of L-mannosyl unit using L-mannosyl fluoride as glycosylating agent. The methods developed in this work would provide new tools to the arsenal of synthesis of L-sugar building blocks and of assembly of glycans containing L-sugar moieties.
All-Polymer solar cells (all-PSCs) have attracted considerable attention due to their inherent advantages over other types of organic solar cells, including superior optical and thermal stability, as well as exceptional mechanical durability. Recently, all-PSCs have experi-enced remarkable advancements in device performance thanks to the invention of polymerized small-molecule acceptors (PSMAs) since 2017. Among these PSMAs, PY-IT has garnered immense interest from the scientific community due to its exceptional perfor-mance in all-PSCs. In this review, we presented the design principles of PY-IT and discussed the various strategies employed in device engineering for PY-IT-based all-PSCs. These strategies include additive and interface engineering, layer-by-layer processing methods, meniscus-assisted coating methods, and ternary strategy. Furthermore, this review highlighted several novel polymeric donor materials that are paired with PY-IT to achieve efficient all-PSCs. Lastly, we summarized the inspiring strategies for further advancing all-PSCs based on PY-IT. These strategies aim to enhance the overall performance and stability of all-PSCs by exploring new materials, optimizing device architectures, and improving fabrication techniques. By leveraging these approaches, we anticipate significant progress in the development of all-PSCs and their potential as a viable renewable energy source.
Lobophorins (LOBs) belong to a large family of spirotetronate antibiotics with antibacterial and antitumor activities. In this study, we demonstrated the function of LobP1, a P450 monooxygenase encoded in the LOB biosynthetic gene cluster, by in vivo deletion and in vitro biochemical assays. The disruption of lobP1 led to the isolation of three new LOBs derivatives (3‒5) and three known ones (6‒8) without the hydroxyl group at C-32. LobP1 was shown to have relatively broad substrate scope. Determing the kinetic parameters of LobP1 towards different substrates revealed that LobP1 preferred substrate with a nitrosugar. The major product LOB E (6) from the ∆lobP1 mutant displayed better cytotoxic activities against several cancer cell lines than LOB B, the C-32 hydroxlated counterpart.
Carbon dots (CDs) are an emerging class of nanomaterials with intriguing photophysical properties. Recently, achieving room-temperature phosphores-cence (RTP) for CDs have attracted considerable attention for biomedical and information applications. However, the CDs based RTP materials generally require the use of polymeric and inorganic matrix to provide the rigid environments, which remains a great challenge to obtain matrix-free CDs with RTP. Herein, a novel supramolecular strategy based on strong interparticle interactions has been developed to attain this objective, by covalent decoration of ureido-pyrimidinone (UPy, a multiple hydrogen bonding unit) on the surface of CDs. Structural characterizations validated the core-shell structure of the as-prepared CDs (EDTA-CDs) and demonstrated the successful attachment of UPy via post-modification (UPy-CDs). The presence of UPy recognition units render the strong hydrogen bonding between UPy-CDs, which stabilizes the triplet state via rigidifying effect. As a result, UPy-CDs exhibit matrix-free efficient RTP (λem = 534 nm) with high brightness and long lifetime (33.6 ms) in the solid state. Owing to the dual-emission character, we further explored the application potential of UPy-CDs in information encryption and anti-counterfeiting. Overall, this work provides a new and facile strategy for achieving matrix-free phosphorescent CDs with elegant incorporation of supramolecular chemistry.
The kinetic process of a slow oxygen evolution reaction (OER) always constrains the efficiency of overall water electrolysis for H2 production. In particular, nonprecious metal electrodes for the OER have difficulty simultaneously possessing good electrocatalytic activity and long-term stability in pH-universal media. In this work, urea is first used as a pore-forming agent and active C/N source to fabricate a nanoporous NiFeCoCN medium-entropy alloy (MEA) by high-temperature sintering based on the nanoscale Kirkendall effect. The NiFeCoCN MEA achieves an overpotential of 432 mV at a current density of 10 mA cm-2 and a lower Tafel slope of 52.4 mV dec-1 compared to the IrO2/Ti electrode (58.6 mV dec-1) in a 0.5 M H2SO4 solution. In a 1 M KOH solution, the NiFeCoCN MEA obtains an overpotential of 177 mV for 10 mA cm-2 and a Tafel slope of 36.1 mV dec-1, which is better than IrO2/Ni foam. This work proves a novel strategy to design and prepare nanoporous MEA materials with desirable C/N species, which provides promising prospects for the industrial production of H2 energy.
One-dimensional semiconductor-metal heterostructures manifest improved charge separation capability, tunable band gap and increased surface area, and have been regarded as promising photocatalysts for solar-to-fuel conversion through water splitting. We herein review the synthetic strategies for the rational design and preparation of one-dimensional semiconductor-metal heterostructures with precise control in terms of size, shape, composition and function. Approaches that are capable of improving the photocatalytic performance of one-dimensional semiconductor-metal heterostructures have been proposed and analyzed The present work is expected to give the rational design of one-dimensional semiconductor-metal heterostructures and provide insights into accomplishing highly efficient photocatalysis based on such materials
C-Glycosides are critical, naturally occurring products and medicinal candidates, and extensive efforts have been made to explore efficient approaches for creating C-glycosidic bonds. Transition-metal-catalysis, particularly nickel-catalyzed C-glycosylation reactions constitute a promising strategy. However, achieving a stereoselective synthesis of α- and β-C-glycosides has been a long-standing challenge. To address this problem, a variety of nickel-mediated strategies have been developed. This review highlights recent developments in the nickel-catalyzed diastereoselective C-glycosylation reactions and briefly summarizes the mechanistic understandings of these methods.
Ultra-narrow bandgap (ultra-NBG) small molecule acceptors (SMAs) show great potential in organic solar cells (OSCs) due to the extend-ed near-infrared (NIR) absorption. In this work, a synergetic alkoxy side-chain and chlorine-contained end group strategy is employed to achieve A-DA’D-A type ultra-NBG SMAs by introducing alkoxy chains with oxygen atom at the second position into the thiophene β posi-tion as well as replacing the F atoms with Cl atoms in the end group. As a result, the heptacyclic BZO-4F shows a redshifted absorption onset (960 nm) than Y11 (932 nm) without oxygen atoms in the side chains. Then, the fluorinated end groups are substituted with the chlorinated ones to synthesize BZO-4Cl. The absorption onset of BZO-4Cl is further redshifted to 990 nm, corresponding to an optical ultra-NBG of 1.25 eV. When blending with the polymer donor PBDB-T, the binary devices based on PBDB-T: BZO-4F and PBDB-T: BZO-4Cl delivers power conversion efficiencies (PCEs) over 12%. Furthermore, ternary devices with the addition of BZ4F-O-1 into PBDB-T: BZO-4Cl system achieve the optimal PCE of 15.51%. This work proposes a synergetic alkoxy side-chain and chlorine-contained end group strategy to achieve A-DA’D-A type ultra-NBG SMAs, which is important for future molecular design.
Fuel-driven dissipative self-assembly, which is a well-established concept in recent years, refers to out-of-equilibrium molecular self-assembly initiated and supported by the addition of active molecules (chemical fuel). It widely exists in nature since many tempo-rary, active micro- or nanostructures in living bodies are generated by the dissipative self-assembly of biomolecules. Therefore, the study on dissipative self-assembly provides a good opportunity to have an insight into the microscopic mechanism of living organisms. In the meantime, dissipative assembly is thought to be a potential pathway to achieve dynamic, temporary supramolecular materials. Recently, a number of temporary materials have been developed with the aid of strategies for realizing dissipative self-assembly. Some of their properties, including solubility, stiffness, turbidity, color, or self-healing ability, change upon the addition of chemical fuel but spontaneously restore with chemical fuel consumption. The dynamic of these materials brings them various unprecedented functions. In this review, the principles of fabricating a fuel-driven temporary material are first reviewed and subsequently, recent examples of fuel-driven temporary materials are emphatically summarized, including gels, self-erased inks, nanoreactors, self-healing materials, and nanochannels. Finally, the challenges of developing fuel-driven temporary materials and some perspectives on the function and application of such kind of materials are discussed.
The study of luminescence phenomena in non-conjugated systems, namely clusteroluminescence, has gained significant attention for the development of advanced luminescent materials. While conventional strategies to manipulate the luminescent performances are based on complicated chemical reactions. In contrast, nature employs complexation to modulate luminescence, inspiring researchers to adopt an engineering approach for the construction of efficient clusteroluminogens. In this work, we explore the complexation-induced clusteroluminescence of carbonyl-based polymers with nitrogen-containing organic bases, exemplified by polyamide, polyester, polycarbonate, and poly(monothiocarbonate). The results demonstrate an increase in the intrinsic 440 nm emission of carbonyl groups and the emergence of new emission peaks upon complexation. The study proposes a through-space n‧‧‧π complex mechanism, highlighting the potential of complexation as a strategy for modulating the clusteroluminescent properties of non-conjugated systems. Further research is necessary to unravel underlying mechanisms, optimize cluster structures, and explore new materials for complexation, thereby advancing optoelectronics and photonics fields and enabling practical applications of clusteroluminescent materials.
By employing thiazole and 4-chlorothiazole as the A′ units, two A-D-A′-D-A type nonfused-ring electron acceptors (NFREAs) Tz-H and Tz-Cl were designed and synthesized. Replacing thiazole in Tz-H with 4-chlorothiazole can not only remarkably shorten the synthetic route through C-H direct arylation but also enhance molecular planarity with the simultaneous incorporation of S···N and S···Cl non-covalently conformational locks (NoCLs). The photovoltaic devices based on PM6:Tz-Cl exhibited a power conversion efficiency as high as 11.10%, much higher than that of PM6:Tz-H (6.41%), mainly due to more efficient exciton dissociation, better and more balanced carrier mobility, less charge recombination, and more favorable morphology. These findings demonstrate the great potential of NoCLs in achieving low-cost and high-performance NFREAs.
Narrow-bandgap n-type polymers are essential for advancing the development of all-polymer solar cells (all-PSCs). Herein, we developed a novel polymer acceptor PNT with π-extended 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene) malononitrile (CPNM) end groups. Compared to commonly used 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1ylidene) malononitrile (IC) units, CPNM units have a further extended fused ring, providing the PNT polymer with extended absorption into the near-IR region (903 nm) and exhibiting a narrow optical bandgap (1.37 eV). Furthermore, PNT exhibits high electron mobility (6.79 × 10−4 cm2 V−1 S−1) and a relatively high-lying lowest unoccupied molecular orbital (LUMO) energy level of −3.80 eV. When blended with PBDB-T, all-PSC achieves a power conversion efficiency (PCE) of 13.7% and a high short-circuit current density (JSC) of 24.4 mA cm−2, mainly attributed to broad absorption (600-900 nm) and efficient charge separation and collection. Our study provides a promising polymer acceptor for all-PSCs and demonstrates that π-extended CPNM units are important to achieve high-performance for all-PSCs.
Energy levels and energy level alignment at interfaces play a decisive role in designing efficient and stable organic solar cells (OSCs). In this review two usually used technologies in organic photovoltaic communities for measuring energy levels of organic semiconductors, photoelectron spectroscopy and electrochemical methods, are introduced, and the relationships between the values obtained from the corresponding techniques are compared. The energy level and energy level alignment across the interfaces involved in solution processed organic photovoltaics are described, and the corresponding integer charge transfer model for predicting and explaining energy level alignment are presented. The effects of the interface properties in designing efficient binary and ternary OSCs were discussed. The effects of environmental factors mainly including water vapor, oxygen gas and thermal annealing on energy levels and energy level alignment involved in photoactive layers, and the subsequent effects on the corresponding OSC properties are given.
Protein glycosylation is the most complex and diverse form of post-translational modification in human body. Meanwhile, glycosylation of peptides and proteins emerges as a promising strategy to improve the pharmacokinetic profile of peptide- and protein-based therapeutics. Owing to the importance of protein glycosylation, rigorous evaluation of the relationship between the precise structure and biological function of glycoproteins has to be per-formed. Recently, chemical synthesis, chemoenzymatic synthesis and semisynthesis strategy have attracted extensive attentions towards the prepara-tion of structurally defined glycopeptides and glycoproteins; the obtained synthetic glycoforms thus enable the thorough investigation of specific effects of protein glycosylation. This review highlights the recent progress in the development of novel strategies, preparation of homogeneous glycoproteins and exploration of structure-activity relationships. On this basis, the challenges and prospects are discussed.
The colonization of marine microorganisms, animals and plants on underwater surface forms marine biofouling. It has profound ef-fects on marine industries. To solve the problem, we proposed a strategy of Dynamic Surface Antifouling (DSAF), i.e., continuously changing surfaces can effectively inhibit biofouling organisms landing and adhering, and developed degradable polymer based ma-rine antifouling material. The degradation of polymer chain enables the surface dynamic or self-renewing even on static conditions. The final degradation products of these polymers are low molecular weight molecules, and do not produce marine microplastics. Meanwhile, the degradable polymers act as carriers and controlled release systems for antifoulants, further improving the antifoul-ing efficiency. This article reviews the development of dynamic surface antifouling materials.
An efficient Pd/Cu-catalyzed oxidative self-carbonylation of arylhydrazine with CO and molecular oxygen as an oxidant to afford symmetrical biaryl ketones via C-N bond activation has been developed. In this approach, arylhydrazine hydrochlorides are used as a green arylating agent which releases nitrogen and water as a byproduct. This developed protocol significantly restricts the for-mation of aryl iodide and homo-coupled azobenzene products even under favorable conditions. A library of symmetrical biaryl ke-tones with wide functionalities was synthesized in good yields under mild conditions.
Usually, the aniline-based late-transition-metal catalysts often require bulky steric substituents on both sides of the ortho-aryl position to achieve efficient suppression of chain transfer in ethylene polymerization. In this contribution, we demonstrated that α-diimine catalysts based on naphthylamine with only one bulky ortho-aryl substituent also demonstrated excellent capabilities to suppress the chain transfer. Firstly, a class of α-diimine nickel and palladium complexes with only one o-aryl-dibenzhydryl or o-aryl-dibenzosuberyl substituent were synthesized and characterized. Secondly, the as-prepared naphthylamine-based nickel catalysts demonstrated outstanding activities and yielded lightly branched (16-40/1000C) polyethylenes with very high molecular weights (445.8-854.3 kg/mol) in ethylene polymerization. In comparison, the corresponding palladium catalysts showed moderate activities, generating moderately branched polyethylenes with moderate molecular weights (21.6-82.0 kg/mol). Moreover, the palladium catalysts could also copolymerize ethylene and methyl acrylate (MA), albeit in low activity (level of 103 g·mol-1·h-1)，providing E-MA copolymers with low to moderate molecular weight (1.4-16.3 kg/mol) and a moderate level of incorporation ratio (2.4-7.4 mol%) and branching density. As compared with aniline-based nickel and palladium catalysts, the naphthylamine-based catalysts displayed a superior ability to suppress the chain transfer reactions and could give access to (co)polymers with orders of magnitude higher molecular weight in ethylene (co)polymerization.