Untying Surface Chemistry and Emulsion Stability to Construct Multifunctional Pickering Emulsion SERS Sensors for Pretreatment-Free Quantitative Analysis in Bio-Media.

Plasmonic Pickering emulsions have immense potential as enhancing substrates in surface-enhanced Raman spectroscopy (SERS). Traditionally, the functional nanoparticles also act as the emulsion stabilizer, so that their surface chemistry is tied directly to emulsion stability. However, this has meant that adsorption of molecules to the plasmonic nanoparticles destabilizes the emulsion system, which severely limits the use of Pickering emulsions in SERS.

Enhancing π-π stacking by a halogen substituent in a single-molecule junction.

Modulating π-π interactions and understanding their impact on charge transport at the molecular scale are critical for advancing supramolecular electronics. Herein, anthracene-based molecular wires (Py-X, X = H, F, Cl, Br) were synthesized and the effect of halogen substituents on π-π stacking was investigated. Experimental results revealed that Py-Br and Py-Cl form both monomer and π-stacked dimer junctions, while Py-H and Py-F only form monomer junctions.

Multiplex imaging of amyloid-β plaques dynamics in living brains with quinoline-malononitrile-based probes.

The dynamic behaviour of amyloid-β (Aβ) plaques in Alzheimer's disease remains poorly understood, and accumulation and distribution of Aβ plaques must be inferred from in vitro pathological changes in brain tissue. In situ detection of Aβ plaques in live imaging is challenging because of the lack of adequate probes. Here we report the design of unimolecular quinoline-malononitrile-based Aβ probes, termed QMFluor integrative framework, that binds in vivo to Aβ plaques, making them detectable via near-infrared fluorescence imaging, magnetic resonance imaging, positron emission tomography and computed tomography.

Catalyst-Free Dynamic Covalent Knoevenagel/Hydrazide Condensation for Polyacylhydrazones and Covalent Adaptable Networks.

The rapid advancement of dynamic covalent chemistry (DCvC) has significantly impacted both chemistry and materials science. There is an increasing need for exploring catalyst-free dynamic covalent reactions with large equilibrium constant (K) ranges to provide new avenues for the tailored design of dynamic polymers. Here, we report a catalyst-free dynamic covalent condensation reaction between Knoevenagel derivatives (Kn) and hydrazides to generate acylhydrazones.

PLLA-PEG/mPEG Copolymer with Improved Hydrophilicity, Crystallinity, and Biocompatibility: An In-Depth Study on the Crystallization Kinetics.

Poly(lactic acid) (PLA) possesses excellent biocompatibility and biodegradability for the construction of biomaterials. However, its limited crystallinity largely restricts practical application. In this study, four poly(l-lactic acid) (PLLA) copolymers were synthesized by incorporating two different molecular weights of PEG/mPEG (1K and 2K) chains with l-lactide via ring-opening polymerization (ROP).

Electronic Structure Origins of Distinct Hydrogenation Activities Observed for Linear and Bent Bimetallic μ-Nitrides.

Hydrogenation of metal nitrides is of particular interest due to the direct relevance to Haber-Bosch ammonia synthesis. Notably, for all bi- and multi-nuclear bridging nitrides reported thus far, only those featuring bent M─N─M cores can react with dihydrogen (H) and related H-derived species, while the vast majority of linear M─N─M congeners cannot. Herein, we present a detailed electronic-structure study of prototypical bimetallic bent μ-nitrides [Cp*Fe(μ-SEt)(μ-N)FeCp*][PF] (1, Cp* = η-CMe) and [Cp*Co(μ-SAd)(μ-N)CoCp*] (3, Ad = adamantyl) and linear μ-nitride [(TPP)Fe(μ-N)Fe(TPP)][PF] (2, TPP = 5,10,15,20-tetraphenylporphinato), as well as μ-imide [Cp*Co(μ-SAd)(μ-NH)CoCp*][BPh] (4), using various spectroscopic techniques, in particular, N solid-state nuclear magnetic resonance, coupled with density functional theory calculations.

Identifying In Situ Activity and Selectivity of Oxygen Reduction Catalysts at the Subparticle Level.

Oxygen reduction reaction (ORR) plays a crucial role in both the chemical and energy industries. Despite substantial advancements in theoretical, computational, and experimental studies, identifying both the in situ activity and selectivity in ORR electrocatalysis remains a major challenge. Here, using a suite of correlative operando scanning electrochemical probe and electrochemiluminescence microscopy techniques, we establish a link between the morphological structure and the local ORR activity and selectivity of single Au and Au@Pt platelets at the subparticle level.

An Atomically Dispersed Pd Sub-Metallene: Intermediate State of Single Atoms and Metal Bonds.

Despite the metal coordination and single-atom catalyst (SAC) have been extensively investigated in surface science over the past decade, their overall activity in involving multi-step reactions remains unsatisfactory owing to the metal bond and single atom being irreconcilable. Here, a stable atomically dispersed Pd sub-metallene (Pd ADSM) layer supported on the 2D MXene (MoTiC) is reported, which combines the advantages of 2D structures, single atoms, and metal bonds. Pd ADSM shows covalent structures along the z-coordination and highly coordinated metal bonds in the 2D direction.

Visualization of photocuring and 4D printing with real-time phosphorescence.

Facile and real-time visualization monitoring of photocuring process is a challenge. Base on the fact that pure organic room-temperature phosphorescence (RTP) is quite sensitive and easy to be regulated via internal rigidity changes of the surrounding environments of phosphore dyes, competitive organic candidates with advantageous RTP are brought into the fields of photocuring and 4D printing materials. Herein, we have put forward a strategy to introduce phosphors into photocuring materials because of the rigidity-increasing liquid-to-solid transformation.

An intrinsic self-healable supramolecular dynamic covalent elastomer for sustainable high-performance tactile sensing.

Supramolecular chemistry empowers polymeric materials with versatile beneficial features encompassing stimulus adaptation, self-healing, to truly function in a biomimetic manner. To seek an effective self-healing mechanism for current polymers with no trade-offs in other property perspectives still remains a challenge. Herein, we present a sustainable alternative to the conventional covalent elastomers, a dynamic covalent disulfide polymer highly crosslinked by bio-catechol hydrogen bonds and coordinative metallic dopants.

Understanding the Position Effects of Monoatom Doping in Silver Nanoclusters on Oxygen Reduction by Single Entity Electrochemistry.

Alloying nanoclusters (NCs) with monoatom doping represents an effective strategy to enhance catalytic performances due to the synergistic interactions between the dopant and host atoms. However, in-depth understanding the position effects of monoatom doping within alloying NCs, particularly at the atomic level, remains elusive. Here, we employed single entity collision electrochemistry method to investigate the electrocatalytic behaviors of individual monoatom-doped bimetallic MAg (M = Ag, Au, Pt, and Cu) NCs toward oxygen reduction reaction (ORR).

A universal strategy for multicolor organic circularly polarized afterglow materials with high dissymmetry factors.

Materials with pure organic circularly polarized afterglow (CPA) have attracted significant attention due to their spatiotemporal-resolved optical properties, yet achieving simultaneous high dissymmetry factor (glum) and multicolor ultralong emission remains a challenge. Here, we establish a universal energy transfer-photon coupling strategy to realize CPA spanning from blue to red with record-high glum (up to 1.90) and ultralong lifetimes (>6 s).

A Reprocessable Dynamic Disulfide Hydrogel for Capacitive Pressure Sensors.

With the rapidly growing demand for wearable sensor devices across a range of applications, sensing technology has been rapidly advancing. However, challenges such as limited sensitivity, device instability, and trade-offs between performance and recyclability remain unaddressed. We report the facile fabrication of a recyclable dynamic disulfide hydrogel from an amphiphilic polyethylene-glycol-based thioctic acid derivative with hydrophilic/hydrophobic characteristics.

Regulating Reversible Untwisting and Twisting Motions in Helical Dynamic Molecular Crystals.

Dynamic molecular crystals with a desirable morphology and controllable responses to external stimuli are highly desired but remain challenging. Here, we present a new photoactive molecular crystal () featuring a naphthalene backbone linked with a vinyl structure and an asymmetric tail. It can undergo reversible head-to-tail [2 + 2] photodimerization under visible light illumination and heating.

Correlating halide segregation of wide-bandgap perovskites with the methoxy group in organic hole-selective materials.

Mixed-halide wide-bandgap (WBG) perovskites are widely used in constructing tandem photovoltaics, but their practical application is challenged by a phenomenon known as photo-induced halide segregation (PIHS), which is detrimental to the stability of the devices. The origin of PIHS is not fully understood yet, restricting the further advancement of mixed-halide WBG perovskites. Here, we report the serendipitous discovery that the PIHS of WBG perovskites is highly related to the presence of the methoxy group (MeO) in organic hole-selective materials (HSMs).

An effective approach to obtain functional poly-β-peptides for combating drug-resistant bacterial infections.

The high mortality of drug-resistant bacterial infections, especially those caused by multidrug-resistant Gram-negative pathogens, highlights an urgent demand for promising antimicrobial strategies. Host defense peptide (HDP)-mimicking poly-β-peptides have demonstrated significant potential in combating drug-resistant bacterial infections, with their antimicrobial activity closely dependent on their side-chain structures. However, the restricted structural diversity of poly-β-peptides necessitates efficient synthetic methods to expand their diversity, particularly positively charged side-chain structures.

Manipulating room-temperature phosphorescence by electron-phonon coupling.

Designing and optimizing efficient organic room-temperature phosphorescent (RTP) materials remains a captivating yet challenging endeavour due to the inherent difficulties in generating and stabilizing triplet excitons. Here, we report a suite of highly efficient phosphors characterized by near-unity intersystem crossing (ISC) yields. Surprisingly, upon doping these dyes into a polyvinyl alcohol matrix, their phosphorescence quantum yields ( ) spanned a wide range from 2.

Tumor Microenvironment-Responsive Polymer Delivery Platforms for Cancer Therapy.

Most chemotherapeutic and bioimaging agents struggle with inadequate bioavailability, primarily due to their limited biocompatibility and lack of specificity in targeting, leading to low or decreased anticancer efficacy and inaccurate imaging. To surmount these obstacles, the development of stimuli-responsive polymer delivery platforms, predominantly leveraging the tumor microenvironment (TME), has emerged as a promising strategy. Therapeutic and diagnostic agents can be released controllably at the tumor site by virtue of the bond cleavage or hydrophobic to hydrophilic transformation of TME-sensitive linkages in TME-responsive systems, thus augmenting cancer treatment and imaging precision, while simultaneously attenuating the damage to healthy tissues and false imaging signals caused by non-specific drug leakage.

Blocking the Operando Formation of Single-Atom Spectators by Interfacial Engineering.

Aside from activity and selectivity, catalyst stability is a key focus in heterogeneous catalysis research. Although sintering of metal species has been considered the primary cause for deactivation of metal catalysts, our study reveals that the loss of activity at low reaction temperatures in the CeO-supported Pt (Pt/CeO) catalyst in complete propane oxidation is due to the dispersion of Pt ensemble sites (nanoclusters) and their subsequent operando conversion into Pt single atoms under reaction conditions. These Pt single-atom species exhibit low reactivity and act as spectators in the low-temperature reaction region.

Enhanced Pyridine-Oxazoline Ligand-Enabled Pd(II)-Catalyzed Aminoacetoxylation of Alkenes for the Asymmetric Synthesis of Biaryl-Bridged 7-Membered -Heterocycles and Atropisomers.

A new class of binaphthyl unit-enhanced pyridine-oxazoline ligands was developed to promote the Pd-catalyzed enantioselective intramolecular 7- aminoacetoxylation of unactivated biaryl alkenes. Biaryl-bridged 7-membered -heterocycles bearing a chiral center were obtained in good yields with excellent enantioselectivities (up to 99:1 er). Computational investigations on a series of biaryl-bridged 7-membered rings provided insights into the rotational barrier of the potentially chiral biaryl unit by the substituent effect including the heteroatom, the protecting group, and the chiral center.

Single-Center Trifunctional Organocatalyst Enables Fast and Controlled Polymerization on -Carboxyanhydride.

Ring-opening polymerization on -carboxyanhydrides (NCA) initiated by primary amines has been the dominantly used method to prepare polypeptides with widespread applications. However, this polymerization chemistry suffers from slow polymerization rate, limited controllability, and difficulty in preparing high molecular weight polypeptides. Herein, we develop a conjugated cationic catalyst featuring cation-dipole interaction, which remarkably enhances the reaction rate and controllability of NCA polymerization, simultaneously, to afford polypeptides in a short time with predictable molecular weights (DP = 20-500) and narrow dispersities.

Algorithm in chemistry: molecular logic gate-based data protection.

Data security is crucial for safeguarding the integrity, authenticity, and confidentiality of documents, currency, merchant labels, and other paper-based assets, which sequentially has a profound impact on personal privacy and even national security. High-security-level logic data protection paradigms are typically limited to software (digital circuits) and rarely applied to physical devices using stimuli-responsive materials (SRMs). The main reason is that most SRMs lack programmable and controllable switching behaviors.

Scaling-up molecular logic to meso-systems via self-assembly.

Due to the small size and biocompatibility of molecules, molecular logic-based computation is a gateway to the informational basis of life processes. Logic-based computation operates widely with discrete molecules of up to nanometric sizes. The contribution of molecule-based bulk materials of milli/centimetric size to the field has begun in more recent years.

Dual-Responsive Ultrathin Peptoid Nanofibers Assembled from Amphiphilic Alternating Peptoids with an Integration of Azobenzene and Histamine Moieties.

Ultrathin organic nanofibers (UTONFs) have favorable potential as emerging nanomaterials due to their large aspect ratio, lightweight nature, and mechanical flexibility. Achieving dual stimuli-responsive UTONFs is necessary to satisfy the on-demand requirements of smart and miniature devices but remains challenging. Herein, amphiphilic alternating peptoids (AAPs) modified with azobenzene and histamine groups were successfully synthesized using the solid-phase submonomer synthesis technique.

Host Defense Peptide-Mimicking Poly(2-oxazoline)s Displaying Potent Activities toward Phytopathogens to Alleviate Antimicrobial Resistance in Agriculture.

Given the limited types of agricultural bactericides and the rapid emergence of antimicrobial resistance, bacterial plant diseases pose a serious threat to agricultural production, which calls for effective antimicrobial agents with a low propensity for resistance. Host defense peptides (HDPs) have drawn significant attention for their broad-spectrum antimicrobial activity. In this study, we found that HPD-mimicking poly(2-oxazoline) Gly-POX exhibits potent activity against bacterial phytopathogens, with superior antibacterial selectivity and proteolytic stability compared to the natural HDP melittin.