The field of chemistry, across its various subdisciplines, has been significantly enriched by advances in understanding carbon intermediates since the 19th century. Among them, carbenes have evolved from transient intermediates to versatile molecular tools, yet integrating luminescence and stimuli-responsiveness in a single system remains a challenge. We report a lithium-bridged carbene-amide hybrid achieves this bifunctional integration. This architecture exhibits intense fluorescence (luminescence efficiency: Phi PL = 85%) and undergoes reversible two-electron cycling among carbene-amido, radical intermediate, and delocalized carbocation states via stepwise single-electron transfers, as demonstrated by crystallographic, spectroscopic, and computational analyses. The asymmetric redox pathway involves N-centered radical formation during oxidation but bypasses this intermediate during reduction, enabling dynamic interconversion. This redox transformation facilitates the direct and reversible conversion between the carbene and carbocation species in a single mechanistic step. Structural studies reveal lithium coordination geometry and charge delocalization underpinning stability. Bridging exciton engineering and dynamic materials science, the work opens avenues for smart molecular technologies in precision synthesis and optoelectronics.

Covalent triazine framework quantum dots (CTF QDs) are promising low-toxicity, high-performance optoelectronic materials featuring molecular-level structural tunability and good charge-carrier mobility. Yet, achieving CTF QDs has long been hindered by the inherently rapid kinetics of triazine cyclization. Here, we overcome this limitation with a simple water-mediated kinetic strategy that modulates the forward Schiff-base reaction rate, thereby delaying triazine cyclization and controlling the degree of amidine-aldehyde polymerization. This approach produces CTF QDs smaller than 3 nm (denoted CTF-QD-1 and CTF-QD-2). By leveraging the pyridinic nitrogen and carbonyl oxygen-functionalized surface of CTF-QD-1 to coordinate interfacial Pb2+ in CsPbBr3 perovskites, we achieve effective defect passivation and controlled crystallization, enhancing the power conversion efficiency from 8.40% to 11.01%-a 31% relative improvement. This efficiency represents one of the highest values reported to date for all-inorganic CsPbBr3 solar cells. This kinetic engineering paradigm addresses the long-standing challenge in synthesizing CTF QDs and unlocks their potential for high-efficiency photovoltaics.

Dearomative addition reactions of indoles represent a prominent strategy for the synthesis of practically valuable indolines. However, implementing this approach typically requires prefunctionalization of the indole precursor with specific groups (e.g., alkynes, alkenes, or ketones) to facilitate the subsequent cyclization-dearomatization step. In this work, we report a three-component, thiol-yne-mediated dearomative vinylation of indoles that circumvents the need for preinstalling reactive fragments into the indole scaffold. The developed photoredox-catalyzed thiol-yne-heteroarene reaction employs Boc-protected indole-3-carboxylates as effective terminating agents for the radical cascade.

Preparing artificial assemblies that can achieve multi-stimuli-responsive and multi-level transformations remains a huge challenge. Here, a pair of dynamic metal-organic tube isomers was prepared from a ligand with multiple coordination modes and flexible conformations. They can undergo multi-level transformations in response to different types of stimuli, including conformational isomerization driven by physical factors (e.g., concentration, temperature, and polarity), adaptive deformations driven by neutral guests, adaptive reconstructions induced by anionic templates. Notably, the guest-driven deformed tubes can continue to undergo reconstruction induced by the PF6 - template, and DMSO can simultaneously serve as a physical factor and a chemical template to continuously regulate isomerization and reconstruction of the dynamic tube. The dynamic tube can be used to regulate the stacking modes of encapsulated 1-formylpyrene and 1-acetylpyrene through adaptive deformations, thereby generating stable guest radicals, enhancing guest fluorescence and achieving white light emission.

Inter-brain region activity coupling is essential for enabling coordinated neural communication, facilitating complex brain processes including motor behaviors. In Parkinson's Disease (PD) patients, cortico-striatal decoupling is widely reported while its onset and cellular mechanism remain largely unclear. Using dual-site fiber photometry and Cre transgenic mouse lines, we examined activity coordination between the primary motor (M1) cortex and dorsal striatum (cortico-striatal coupling) with cell-type resolution. This method identifies motor behavior-specific coupling patterns with different contributions from striatal D1R- and D2R-expressing medium spiny neurons (MSNs). In an alpha-synuclein preformed fibrils (PFF) induced PD-like mouse model, cortico-striatal coupling associated with digging behavior is selectively disrupted as early as two months post-induction, whose progressive deterioration correlates with later-onset behavioral deficits. Optogenetic disruption or enhancement of cortico-striatal coupling is sufficient to induce digging deficits in wild-type mice or rescue such deficits in PFF-injected mice, respectively. Furthermore, such decoupling is mainly mediated by impaired D1R MSNs, which can be rescued by D1 receptor activation or L-DOPA. These findings demonstrate that early-onset, behavior- and cell type-specific cortico-striatal decoupling emerges early during the development of PD-like symptoms.

The self-assembly of peptides into amyloid fibrils enables the design of functional biomaterials, yet the conformational constraints of alpha-peptides limit the attainable supramolecular diversity. Here, we introduce beta-amino acids, beta-phenylalanine (beta-Phe), and beta-homophenylalanine (beta-hPhe) into the reversible fibril-forming core sequence hnRAC1 to generate alpha/beta-peptide variants with distinct architectures and enhanced thermal stability. Cryo-EM reveals that beta-modified peptides assemble into polymorphic fibrils with cross-beta structures that differ markedly from each other and from native hnRAC1. Comparative structural analysis indicates that backbone extension by beta-residues increases subunit conformational heterogeneity, enabling tighter packing and formation of more thermostable fibrils. Examination of intra- and intermolecular contacts shows that enhanced pi-pi stacking, hydrophobic interactions, hydrogen bonds, and electrostatic interactions likely contribute to fibril stabilization. These results show that minimal backbone modifications can remodel amyloid architecture, offering a generalizable strategy for designing structurally diverse and robust peptide-based biomaterials.

Scandium-modified carbon dots (Sc-oCDs) were synthesized in this work through a solid-phase approach. The prepared Sc-oCDs exhibited excitation-independent emission properties, as well as photostability against pH, ionic strength, and UV irradiation. Their fluorescence quantum yields significantly exceeded those of unmodified counterparts, confirming effective Sc modification. The Sc-oCDs also possessed upconversion fluorescence at 542 nm with 980 nm excitation. Additionally, the as-prepared Sc-oCDs functioned as an effective fluorescent sensor for Cu2+, demonstrating selective fluorescence quenching. A linear correlation was observed between the quenching efficiency and Cu2+ concentration from 1 to 600 mu M, achieving a detection limit of 0.167 mu M. Operating via dynamic quenching, this sensing system achieved highly selective and rapid (<1 min="">

A cobalt-catalyzed protocol for diastereo- and enantioselective reductive coupling of unactivated cyclobutenes and aldimines through oxidative cyclization promoted by a chiral bisphosphine-cobalt is presented. Such processes represent an unprecedented reaction pathway for cobalt catalysis that enable umpolung reactivity of cyclobutenes with imines and incorporation of a chiral amino-containing fragment onto the four-membered ring scaffold, delivering a broad scope of enantioenriched cyclobutyl amines in up to 98% yield and >99.5:0.5 er as a single diastereomer. Functionalization provided a variety of densely functionalized cyclobutanes that are otherwise difficult to access. Preliminary mechanistic studies revealed that the reaction proceeded through diastereo- and enantioselective oxidative cyclization followed by protonation. Density functional theory calculations elucidated the origin of stereoselectivity in detail.