Accounts of Chemical Research最新文献

Photoelectronic surface and interface chemistry plays a pivotal role in addressing global challenges in energy conversion, environmental sustainability, and intelligent manufacturing. Recent years have witnessed notable progress in this field, particularly in the development of chemical sensors, intelligent surfaces, and artificial photosynthetic systems, all grounded in the principles of photoelectronic surface and interface chemistry. The functionality of these systems depends critically on the photophysical properties of the molecular components, their spatial arrangement at interfaces, and the dynamics of interfacial electron transfer. However, the diversity of photoelectrochemical molecules, spatial constraints at surfaces and interfaces, and the complexities of interface coupling often introduce significant randomness and structural complexity, posing challenges for both fundamental research and practical applications. Over the past decade, we have developed a unique class of chalcogenoviologen-based systems that enable tuning photoelectronic behavior at surfaces and interfaces. By integrating molecular design with interfacial assembly, these systems provide a versatile platform for constructing functional optoelectronic architectures. This Account provides an overview of the design and synthesis of novel chalcogenoviologen derivatives, highlighting synthetic strategies that enhance spin–orbit coupling, reduce energy gaps and reduction potentials, and allow fine-tuning of photoelectric properties. Further, it discusses assembly methods for constructing chalcogenoviologen-based surfaces and interfaces through electrostatic, hydrogen bonding, and covalent strategies, with particular emphasis on multicomponent covalent and noncovalent architectures that enable controlled energy level alignment and directional electron transfer. This Account also presents our selected contributions to the application of these functional surfaces and interfaces across areas such as photocatalysis, electrochromic devices, energy storage, and intelligent visual sensing. The focus is particularly given to emerging applications in photo/sonodynamic therapy, electrochromic display, and aqueous organic redox flow batteries. Finally, this Account offers a perspective on the potential of molecular-level interface design in advancing next-generation optoelectronic technologies.

Carbon-based materials are widely investigated as sustainable electrodes for energy conversion, storage, and environmental remediation. Yet, pristine carbons with perfect sp²-hybridized hexagonal lattices usually exhibit limited electrochemical reactivity. This is primarily due to their ordered layered crystal structure and intrinsic electronic neutrality, which results in a lack of unsaturated coordination sites required for small-molecule activation. Therefore, the structural engineering of the carbon matrix is highly critical to addressing this bottleneck.

Introducing pentagon motifs into carbon frameworks serves as an effective approach to breaking the planar lattices and electronic neutrality of pristine carbon. Specifically, the pentagon motifs induce geometric curvature and electronic modulation, thereby endowing the material with excellent performance in a range of electrochemical applications. Despite this potential, the controlled synthesis of pentagon-enriched carbons remains a long-standing challenge.

To tackle this issue, our group has leveraged the inherent carbon pentagonal rings in fullerenes as a unique entry point, pioneering pathways for the construction and precise regulation of pentagons in carbon frameworks. Over the past decade, we have focused on developing carbon materials with intrinsic pentagon motifs and made progress in their controllable synthesis, functional modulation, and multilevel structural evolution.

In this Account, we will summarize our recent progress on the controlled synthesis of pentagon-enriched carbon materials and their electrochemical applications. We first present promising practices to achieve the controlled incorporation of pentagon units into extended carbon frameworks under fullerene-reconstructed methodologies. We further highlight the advanced characterization techniques and theoretical investigations in determining the presence and functions of pentagonal rings in carbon frameworks. Based on these structural insights, we discuss their properties in electrochemical processes and highlight their relevance to applications. Finally, perspectives on the challenges and future opportunities of this emerging field are proposed. The strategies and insights presented herein not only establish a foundational framework for pentagon engineering in carbon materials but also offer guidelines for designing functional nanomaterials across energy and environmental applications.

Alkali metal (AM) cations are often taken for granted as counterions in coordination chemistry and organometallic reactions. However, the AM cation can be more than a bystander in inorganic transformations. This Account focuses on research that has elucidated several types of AM cation effects and how these can be exploited to achieve novel structures and reactivity pathways. A particular focus is on AM cation effects in low-coordinate iron β-diketiminate complexes, though we address general trends and potential applications in systems with other supporting ligands.

The Account is organized by several recurring motifs and trends in how AM cations interact with transition-metal compounds: (1) the AM cations can stabilize and favor the formation of N₂-bridged compounds, (2) the choice of AM cations can influence N–N bond cleavage, (3) the AM cations can influence other bond forming and cleaving reactions, and (4) AM cations can affect ligand binding modes and electronic structure at the metal center. Various methods including X-ray crystallography, density functional theory (DFT) calculations, Mössbauer spectroscopy, and vibrational spectroscopy are leveraged to show how the AM cation affects a given system.

The results of these studies have more general lessons as well. They offer insights into how ligand design can be leveraged to promote or discourage AM cation interactions. AM cations can be used to activate challenging bonds and/or stabilize highly reactive species. The cooperative interactions described in this Account may offer new paths to reactivity in organometallic chemistry and small molecule activation.

The imperfect atomic interfaces (IAIs) refer to the interface area with incomplete crystal structure formed by precise atomic-scale structure modulation. Unlike the traditional perfectly crystalline interfaces, IAIs show structural defects and symmetry breaking in their atomic arrangement and coordination environment. These characteristics can be achieved by accurately adjusting the spin state, orbital electron configuration, or charge distribution of the interface atom. Therefore, IAIs have become a promising strategy to overcome the inherent activity limitations of traditional catalysts. However, the inherent instability of IAIs in energy conversion and storage systems poses major challenges. Therefore, the precise construction and stability of IAIs with customized defect configurations are crucial for fundamental research and large-scale industrial catalysis.

The construction of IAIs depends on multiscale structural regulation, mainly including strategies such as interface space limitation, template-guided assembly, and competitive chemical bond modulation. Among them, the spatial limitation effect aims to take advantage of the local constraints of the defect carriers, while the template-guided assembly aims to induce uneven charge distribution in the polymetallic system so as to regulate the electronic structure and surface energy state and promote the formation of IAIs. In particular, competitive chemical bond modulation through heteroatomic coordination will destroy the symmetry of metal centers, fine-tune the d-band center, and promote electron transfer, thus promoting the functional evolution of the interface. Collectively, these multiscale operations expose highly active unsaturated sites and optimize electron transfer pathways. At the same time, the combination of theoretical calculation and in situ characterization provides important guidance for accurate construction of the catalytic interface. In addition, it can also comprehensively analyze the intrinsic relationship between the catalyst structure and catalytic performance. Therefore, it is of great significance to promote future development to systematically summarize the research results in this field and deeply explore the application of high-efficiency industrial catalysts with an optimal interface atomic arrangement.

Building on our 2016 discovery of symmetry breaking in wurtzite ZnSe nanocrystals, we realized that imperfections underlie the functional characteristics. In this Account, we systematically summarize the design and functionalization strategies of IAIs developed by our team around electronic degrees of freedom over the past decade and elucidate their unique roles in the synthesis of high-value chemicals and the catalytic transformation of small molecules. Through rational interfacial manipulation and performance design, IAIs provide a theoretical framework and feasible methods for the development of high-performance catalysts.

Light offers a clean and precise means to control chemical processes. These advantages have opened the door to the development of dynamic host–guest systems, whose functions can be turned on or off with specific wavelengths. Over recent years, we have developed a suite of light-responsive metal–organic capsules that use azobenzene photoisomerization to direct functions that include reversible guest encapsulation, selective molecular separations, controlled catalysis, and directional mass transport. These capsules, assembled via subcomponent self-assembly, incorporate azobenzene-based ligands that undergo photoinduced trans–cis isomerization. This reversible switching induces cage disassembly or changes in host–guest binding, enabling light to act as an external signal to modulate activity.

In this Account, we summarize five key studies that trace the evolution of this platform, from basic molecular recognition and guest release to complex, multicomponent systems capable of energy transduction and spatial molecular control. We describe (i) the design and mechanistic studies of phototriggered guest release using a tetrahedral Zn₄L₄ cage; (ii) the use of an architecture built on this initial work to purify progesterone selectively from mixed steroidal systems; (iii) light-gated catalytic activation using a caged perrhenate system; (iv) selective lithium ion extraction using photoswitchable sandwich architecture; and (v) a Maxwell’s Demon-inspired setup that achieves directional molecular pumping across centimeter-scale distances. Collectively, these studies demonstrate how light-responsive metal–organic capsules can be programmed to perform diverse chemical functions, including guest release, selective separations, catalysis, ion extraction, and directional transport. This body of work establishes a platform for the future development of integrated, autonomous, and energy-efficient light-driven supramolecular technologies.

Contact electrification (CE) is a ubiquitous interfacial phenomenon in which charge transfer occurs when two materials come into contact and subsequently separate. Remarkably, a growing body of evidence shows that CE can initiate and sustain a wide range of chemical reactions without the need for conventional thermal or photonic activation. In particular, solid–liquid CE has recently emerged as a versatile platform for sustainable chemistry, characterized by broad material compatibility, in situ radical generation, and the ability to drive diverse redox transformations. Besides, reactions occurring at gas–liquid and immiscible liquid–liquid interfaces often proceed orders of magnitude faster than in the bulk phase, underscoring the unique reactivity associated with interfacial environments. Despite these advances, the fundamental driving forces behind CE-induced chemistry remain contested, including the pathways of charge transfer and the mechanisms by which interfacial charges influence reaction coordinates. This perspective focuses on the interplay among solid–liquid CE, interfacial electron and ion transfer, and the localized triboelectric fields established during CE. By highlighting the triboelectric field as an intrinsic, tunable driving force capable of modulating interfacial reactivity, we advance the view that CE offers a distinct platform for reagent-free, sustainable chemical transformations.

ObjectiveThymic cysts are rare benign neck masses, accounting for less than 1% of all cervical masses. This study aims to discern different presentations, investigations, and treatment options of thymic cysts in adults by reviewing prior published studies from January 2010 to October 2021 to bridge the knowledge gap since the last review by Michalopoulos in 2011. Moreover, we present a case of a 28-year-old male with a left cervical thymic cyst.Data sourcesData were obtained from a literature search using the ScienceDirect, PubMed, ResearchGate, and Google Scholar databases.Methods and resultsThis study retrospectively analyzes reported cases of adult cervical thymic cysts by collecting demographic data, patient presentation, duration, location, size, type of imaging, fine-needle aspiration, and surgical approach. Eighteen patients were included. Cysts were seen on the left (n = 9), right (n = 5), and midline (n = 4). The age of the patients ranged from 19 to 64 years. Most patients present with painless left-sided neck swelling. Computed tomography (CT) was the preferred imaging modality in most cases. Moreover, surgical excision was essential for therapeutic and diagnostic purposes. This study did not require institutional review board approval.ConclusionAdult cervical thymic cyst is a rare etiology. Nevertheless, a painless left-sided neck mass with no clear lower border should uphold thymic cyst as a differential diagnosis. MRI and CT scans are the preferred imaging modalities for preoperative planning. Surgical excision is mandatory for treatment and histological confirmation. As of October 2021, around 54 cases of adult thymus cysts had been reported to the best of our knowledge and review.

Background: Ethnography has been used to address a broad range of research questions in health care. With ethnographic research methods it is possible to gain access to the complex realities of health care practice as it occurs, through interpreting the nuances of individual and team behaviours, the roles and dynamics of care provision, and the social impacts and influences of illness. The provision of clinical palliative care is complex, involving multidisciplinary collaboration across different health systems, and is subject to a multitude of personal, cultural and environmental influences. This complexity demands creative methodological approaches to research in palliative care, of which ethnography plays an important, if infrequently utilised, role. Aim: This article aims to explore potential opportunities of ethnographic methods for palliative care research. Findings: Ethnographic methods focuses on behaviour in the 'natural' setting of participants, to create theoretical descriptions of events, cultures, interactions and experiences. In palliative care these methods may provide nuanced understandings of illness, relationships and teams, communication, medical education, complex care provision, and novel or changing health practices. Of particular importance is the potential of these methods to understand complex practices and processes, and engage with under-represented population groups who may be excluded from interview research. Conclusion: Ethnography offers important opportunities for future research in palliative care and should be considered as part of the 'research toolbox' to improve understanding of the complex nature of care provision and the experiences of illness and loss.