Macrocycles play pivotal roles in supramolecular chemistry and materials science because of their distinctive molecular recognition capabilities and versatile applications in self-assembly. However, traditional macrocycles, such as cyclodextrins, calixarenes, cucurbiturils, and pillararenes, have inherent limitations in terms of cavity size and structural variety, which restrict their ability to encapsulate guest molecules of varying sizes and their potential in constructing multifunctional materials. To address these challenges, our group has developed a simple, universal, and modular strategy for constructing functional macrocycles, termed biphen[n]arenes. This approach leverages structure- or function-oriented modular replacement of reactive, functional, and linking modules. Therefore, biphen[n]arenes with customized cavity size and molecule depth can effectively encapsulate guests from small molecules to biomacromolecules. On the other hand, different from modification of side chains, incorporation of functional primitives into the biphen[n]arene scaffold can leave active sites on both edges to induce additional moieties to improve recognition potency or integrate extra application functionality. These characteristics provide significant advantages in the construction of diverse supramolecular materials.This Account summarizes the research progress on biphen[n]arene-based supramolecular materials across three major areas: (a) Biomedical materials. By customizing the sizes, shapes, and portal substituents of biphen[n]arenes to match the structural features of biomedical molecules such as drugs, bioactive peptides, and macromolecular biotoxins, we have constructed a series of water-soluble biphen[n]arenes with exceptional recognition capabilities. These biphen[n]arenes demonstrate a range of promising applications, including reversing neuromuscular blockers, combating bacterial infections, delivering peptide agents, detoxifying macromolecular biotoxins, and disassembling fibrous proteins. (b) Luminescent materials. We developed a series of luminescent macrocycles by introducing diverse fluorophores and phosphors onto biphen[n]arene skeletons, which displayed enhanced emission compared to the corresponding monomers. The modular approach provides an efficient and universal strategy for enhancing solid-state emission, termed macrocyclization-induced fluorescence/phosphorescence enhancement. Additionally, structurally diverse luminescent macrocycle cocrystals have been obtained, where solid-state luminescence can be precisely tuned by controlling donor-acceptor stoichiometric ratios and molecular packing modes. (c) Adsorption and separation materials. Biphen[n]arenes and cages exhibit impressive separation capabilities for industrially important mixtures owing to their advanced architectures and diverse supramolecular interactions. These include the separation of cis-/trans-1,2-dichloroethene isomers, benzene/cyclohexane, toluene/methylcyclohexane, cyclohexane/cyclohexene/benzene, cycloheptane/cycloheptene, and tetrahydronaphthalene/naphthalene mixtures. Supramolecular organogels of larger macrocycles, such as terphen[5,6]arenes and quaterphen[5,6]arenes, demonstrate more effective iodine capture in both aqueous and gaseous environments compared to their powder states. After detailing the significant contributions and potential of biphen[n]arenes in creating multifunctional supramolecular materials, this Account also discusses the existing challenges and future directions related to the structures, properties, and applications of biphen[n]arenes. We hope to inspire interdisciplinary researchers and provide new opportunities for the development of advanced functional materials.
Abstract Solar fuel production, which primarily focuses on harnessing solar energy to convert CO2 into fuels or produce H2 through water splitting, holds transformative potential for addressing global energy demands and environmental challenges. However, several obstacles still need to be overcome, particularly concerning the efficiency and scalability of solar fuel systems. Plasmonic-metal/semiconductor nanohybrids (PSNs) represent a cutting-edge class of photocatalysts designed to overcome current efficiency bottlenecks by merging the unique localized surface plasmon resonance (LSPR) properties of plasmonic metals with the catalytic efficiency of semiconductors, thereby enhancing the overall efficiency of light-driven solar-to-fuel conversion. Precise regulation of PSN structures is essential for guiding the extraction and flow of energy and charge carriers within the nanohybrids, which ultimately determines their photocatalytic performance. In this perspective, we aim to highlight the direct impact that the configuration of these nanohybrids has on the efficiency of solar fuel production through various triggered plasmonic energy transfer mechanisms. To this end, we begin with a brief introduction to the basic plasmonic effects and fundamental energy transfer mechanisms between plasmonic metals and semiconductors. We then provide representative examples of how PSNs with five categories of engineered configurations (namely, core–shell, yolk–shell, Janus/heterodimer/dumbbell, core–satellite, and other hierarchical structures) enhance solar fuel production through three primary mechanisms: plasmon-induced resonance energy transfer, light absorption/trapping, and hot electron injection. We conclude this Perspective by outlining the remaining challenges and research directions in this field.
Electrochemical carbon dioxide reduction (CO2RR) driven by renewable electricity, such as solar power, presents a promising pathway for sustainable energy conversion. However, system performance and stability are challenged by intermittent operation due to renewable energy supply or industrial process halts. Herein, we investigate the impact of intermittent operation on zero-gap CO2 electrolyzers. We reveal that intermittent operation induces flooding in the microporous layer (MPL) of the gas diffusion electrode (GDE), driven by pressure differentials and hydrophobicity degradation. This flooding impedes CO2 transport and promotes the hydrogen evolution reaction (HER). To mitigate this effect, we propose the use of electrowetting-resistant and nonconductive GDEs, with polytetrafluoroethylene (PTFE) as a proof of concept, which effectively mitigates flooding and maintains CO2RR selectivity under intermittent conditions. Our findings provide critical insights into the design of resilient CO2RR systems capable of stable operation under the dynamic conditions of renewable energy integration.
The flavor and aroma development in fermented foods is intricately tied to the mixing dynamics during fermentation. This review explores how variations in mixing influence the physical, chemical, and microbial interactions within fermentation systems, ultimately affecting sensory characteristics such as flavor and aroma. Factors, such as rheology, shear forces, and fluid flow patterns, are critical in mass transfer, microbial activity, and the release of volatile compounds, contributing to fermented products' sensory profile. Examples from common fermented foods—including bread, yogurt, beer, wine, and cheese—highlight how controlled mixing can optimize the release of desirable flavor compounds, improve biosynthesis yields, and reduce technological complexity. Understanding these physical interactions is essential for advancing fermentation processes in the food industry, leading to a higher product quality, a better flavor retention, and an enhanced consumer satisfaction.
Records of sunlight intensity at anthesis of 388 rice landraces (with 32 replicated populations), flowering in the short-day season of 2022, reveal that under cloudy condition, the rice florets tend to open later, or the sunrise-to-anthesis duration (SAD) is longer when rice florets open than at sunny period. This difference in the length of SAD was statistically highly significant (p < 0.0001), confirmed by a two-sample permutation test with 10,000 iterations. This finding corroborates our general observation previously reported from a larger set of 1114 landraces (including the 388 landraces examined in this study). However, the intensity of sunlight at the flower opening time (FOT) may not remain uniformly sunny (high illuminance) or cloudy (low illuminance, < 40,000 lx) until the flower closing time (FCT). To understand the effect of uniformly low sunlight intensity, we subsequently recorded solar illuminance at FOT of 33 landrace populations (including 8 repeats). Half of each population was kept under artificial shade, compared to the other half exposed to sunlight. This experiment revealed that low illuminance, mimicking overcast days, significantly (p < 0.02) delays FOT and lengthens SAD, corroborating the pattern detected in our earlier findings. Permutation test with 10,000 iterations decisively confirms (p < 0.0001) the prolongation of SAD under shade and cloudy conditions. Experimental shading has an indeterminate effect on flower exposure duration (FED) of the same landraces. We surmise that the delayed FOT during natural cloudy period is an adaptation in rice plants in anticipation of rain, for protection of the pollen from rainwash.
