Jianhua Su

Molecular topology governs the photophysical properties of polycyclic π-conjugated systems by defining their effective conjugation pathways. Conventionally, linear π-extension is considered more effective than angular extension in increasing the effective conjugation length and narrowing the optical bandgap. Here we uncover an inverse topology–property relationship in π-extended dihydrophenazines (DHPs): linear extension unexpectedly blueshifts fluorescence, whereas angular extension produces pronounced redshifts. Transient spectroscopy, theoretical calculations and aromaticity analyses reveal that Baird aromaticity–driven planarization of the DHP core redistributes π-delocalization in the S1 state, causing linear fusion to disrupt global π-delocalization and shorten the effective conjugation length, while angular fusion promotes cooperative delocalization across the fused framework and extends it. Successive angular fusion progressively activates four structurally distinct π-extension branches through the shared Baird-aromatic DHP core, generating an X-shaped multichannel conjugation network. These findings reveal how excited-state aromaticity reprograms conjugation topology, offering new insights for controlling π-delocalization and emission.

A conformation-dependent bifunctional sensor is developed by capitalizing on a vibration-induced emission chromophore for viscosity sensing and an acid-triggered oxazolidine switch for pH sensing.

Elucidating pathway-specific ferroptosis mechanisms is crucial for advancing our understanding of cell death regulation; however, this goal has been hindered by the persistent absence of reliable detection techniques and standardized analytical approaches. Mechanistically, ferroptosis is governed by the nexus between Glutathione Peroxidase 4 (GPX4) inactivation and lipid-peroxide-driven membrane destabilization, with cysteine (Cys) as a key regulator for GPX4 synthesis and ferroptosis trigger differentiation. Lipid peroxide accumulation elevates cytoplasmic viscosity, enabling the decryption of ferroptosis-trigger mechanisms by elucidating Cys-viscosity dynamics. For this, we engineer an innovative dual-parameter sensing platform: a conformationally flexible molecular scaffold with triple-emission viscosity sensitivity was functionalized with a Cys-reactive aldehyde group. This probe system features a fluorescence quenching mechanism and then sequentially restores red and blue fluorescence in the presence of Cys and high viscosity. Notably, while distinct ferroptosis pathways induce an observable viscosity increase, the Cys flux profiles exhibit pathway-specific signatures. Direct synthesis blockade displays a remarkable Cys fluctuation (Δ[Cys] = 20%, 4 h) compared to GPX4 inhibition (Δ[Cys] = 21%, 12 h), whereas overload iron demonstrates imperceptible variation (Δ[Cys] = 28%, 36 h latency). Furthermore, the evaluation of Cys-dependent ferroptosis in pancreatic cancer models uncovers therapy response mechanisms. This work highlights the key role of Cys and viscosity kinetics in ferroptosis initiation and execution phases, advancing the fundamental research and precise regulation of ferroptosis.

High efficiency in red phosphorescent OLEDs (PhOLEDs), significant EQE enhancement in green PhOLEDs with a co-host, outstanding thermal stability and bipolar transport balance are achieved through strategic HOMO engineering in this study.

X87 is a novel π-conjugated hole transport material (HTM) featuring an SFX core and anthracene substituents. Its planar structure enhances π–π interactions with t BP, enabling PSCs to achieve 24.07% PCE and excellent long-term stability.

Two vibration-induced-emission-based fluorophores, namely DPAC-Me and DPAC-CF₃, exhibit triple fluorescence emissions and demonstrate high sensitivity to viscosity across a broad viscosity range. In addition to the normal viscosity ranges (1–1000 cP), DPAC-CF₃ also shows high sensitivity to viscosity in both very low ranges (0.3–1 cP) and extremely high ranges (1000–72 330 cP).

Cisplatin is a common chemotherapy drug for multiple solid tumors; however, due to the nitrification of peroxynitrite (ONOO^-), a series of side effects seriously affect its dose and efficacy. Considering that the reactivity of ONOO^- is significantly affected by pH in vitro, revealing their roles in living cells contributes to understanding the side-effect process induced by cisplatin. Herein, we present a near-infrared fluorescent logic gate for sensing pH/ONOO^-, which can accurately discriminate four scenarios (no analyte, analyte H⁺ alone, analyte ONOO^- alone, and H⁺ + ONOO^-) and which one comes first. With this probe, the significant roles of pH and ONOO^- in cisplatin treatment are disclosed, in which the cell account shows a dramatic reduction accompanied by decreased pH and upregulated ONOO^- levels. By artificially recovering the pH, the ONOO^- content and cell account can maintain a stable state, possibly due to the protection from acidification and nitration. This work provides an ideal pH/ONOO^- logical sensor for revealing their potential roles under cisplatin, which is expected to proffer new insights into more related diseases and drug research.