Sulfone-Functionalized Chichibabin's Hydrocarbons: Stable Diradicaloids with Symmetry Breaking Charge Transfer Contributing to NIR Emission beyond 900 nm.

While monoradical emitters have emerged as a new route toward efficient organic light-emitting diodes, the luminescence property of organic diradicaloids is still scarcely explored. Herein, by devising a novel radical-radical coupling-based synthetic approach, we report a new class of sulfone-functionalized Chichibabin's hydrocarbon derivatives, SD-1-3, featuring varied substituent patterns and moderate to high diradical characters of 0.44-0.70, as highly stable diradicaloids with rarely seen NIR emission beyond 900 nm. Via comprehensive experimental and theoretical investigations, we reveal that the optoelectronic and magnetic properties of these materials are significantly tuned by the variations of substitutions (H/CF3/OMe) on the molecular skeletons. More importantly, quantum chemical computations indicate that the embedding of sulfone groups has contributed to a breaking of their quasi-C2 symmetry of these diradicaloid molecules and results in an excited-state charge transfer character. Therefore, a remarkably deep NIR emissive wavelength of up to 998 nm, together with a large Stokes shift (∼386 nm), is achieved for the CF3-based SD-2 molecule in tetrahydrofuran. To the best of our knowledge, such a luminescent wavelength of SD-2 has represented the longest wavelengths among the currently reported organic fluorescent radicals. Overall, our work not only establishes a new synthetic approach toward stable Chichibabin's hydrocarbons but also paves the way for designing NIR emissive open-shell materials with both fundamental understanding and feasible control of their luminescent properties.

Fluorogenic in-situ Labelling of Gelatin Polymer in Aqueous Solution and Hydrogel.

Gelatin polymers made from partially degraded collagen are important biomaterials, but their in-situ analysis suffers from uncontrollable covalent labelling and poor spatio-temporal imaging resolution. Herein, three tetrazolate-tagged tetraphenylethylene fluorophores (TPE-TAs) are introduced for practical fluorogenic labelling of gelatin in aqueous phase and hydrogels. These probes with aggregation-induced emission characteristics offer negligible background and elicit turn-on fluorescence by simply mixing with the gelatin in aqueous phase, giving a detection limit of 0.15 mg/L over a linear dynamic range up to 100 mg/L. This method does not work for collagens and causes minimal interference with gelatin properties. Mechanistic studies reveal a key role for multivalent electrostatic interactions between the abundant basic residues in gelatin (e.g., lysine, hydroxylysine, arginine) and anionic tetrazolate moieties of the lipophilic fluorophore synergistically in spatially rigid macromolecular encapsulation to achieve fluorogenic labelling. The AIE strategy by forming non-covalent fluorophore-gelatin complexes was developed for novel hydrogels that exhibited reversible fluorescence in response to dynamic microstructural changes in the hydrogel scaffold upon salting-in/out treatments, and enabled high spatio-temporal imaging of the fiber network in lyophilized samples. This work may open up avenues for in-situ imaging analysis and evaluation of gelatin-based biomaterials during processes such as in vivo degradation and mineralization.

α-Cyano Triaryl[3]radialene: Unsymmetrical Stereo-configuration, Clustering-enhanced Excimer Emission, and Radical-involved Multimodal Information Switching.

[3]Radialene has a peculiar topology and cross-conjugation system, representing a unique molecular scaffold in organic materials. Herein, we report a special class of stereoisomeric α-cyano triaryl[3]radialenes (CTRs) that show concentration-caused quenching in solution but emit red-shifted and enhanced luminescence in the crystalline state. Clustering of multiple cyano groups and their through-space interactions with the [3]radialene ring significantly extend π-electron communication meanwhile rigidifying the propeller conformation multivalently, thus playing a key role behind the state-dependent luminescence. These radialenes with a substantial electron affinity undergo a reversible electron transfer transition to anionic radicals with good stability, showing switching of photoabsorption, photoluminescence and electron spin resonance (ESR) signal. We also established proof-of-concept applications of CTRs for multimodal information encryption and chemical sensing.

Spiro-Functionalized Diphenylethenes: Suppression of a Reversible Photocyclization Contributes to the Aggregation-Induced Emission Effect.

Many aggregation-induced emission (AIE) materials are featured by the diphenylethene (DPE) moiety which exhibits rich photophysical and photochemical activities. The understanding of these activities behind AIE is essential to guide the design of fluorescent materials with improved performance. Herein by fusing a flexible DPE with a rigid spiro scaffold, we report a class of novel deep-blue material with solid-state fluorescent quantum yield (ΦF) up to 99.8%. Along with the AIE phenomenon, we identified a reversible photocyclization (PC) on DPE with visible chromism, which is, on the contrary, popularized in solutions but blocked by aggregation. We studied the steric and electronic effects of structural perturbation and concluded that the PC is a key process behind the RIMs (restriction of intramolecular motions) mechanism for these materials. Mitigation of the PC leads to enhanced fluorescence in solutions and loss of the AIE characteristics.

Clinical Value of Controlling Nutritional Status Score in Patients with Aneurysmal Subarachnoid Hemorrhage.

OBJECTIVE: The aim of present study was to assess the predictive value of the admission prognostic nutrition index (PNI), controlling nutritional status (CONUT) associated with delayed cerebral ischemia (DCI), and 3-month neurological outcomes after aneurysmal subarachnoid hemorrhage (aSAH). METHODS: The clinical data from 252 patients with aSAH were retrospectively analyzed. Receiver operating characteristic analysis was performed to assess the predictive ability of the PNI and CONUT score and identify the cutoff point. Multivariate analysis was conducted to assess the role of the PNI and CONUT score in predicting for DCI and outcomes at 3 months after aSAH treatment. RESULTS: We enrolled 252 patients with aSAH in our study. Of the 252 patients, 53 experienced DCI and 57 patients had a poor outcome. Patients with unfavorable outcomes had a lower serum albumin, lymphocyte count, total cholesterol, and PNI but a high CONUT score, Hunt-Hess grade, and aneurysm size (P < 0.05). Both the PNI and CONUT score correlated with the Hunt-Hess grade (r = -0.289 and P < 0.001; r = 0.512 and P < 0.001), modified Rankin scale score at 3 months (r = -0386 and P < 0.001; r = 0.533 and P < 0.001), aneurysm size (r = -0.219 and P < 0.001; r = 0.422 and P < 0.001). Only a CONUT score <4 (odds ratio, 0.241; 95% confidence interval, 0.071-0.842; P = 0.022) independently predicted the functional outcome status but not DCI at 3 months after aSAH. However, PNI was an unrelated factor associated with DCI and the clinical outcome. CONCLUSIONS: Our results have indicated that the CONUT score might efficiently predict for the clinical outcomes at 3 month after aSAH.

Specific and Quantitative Detection of Albumin in Biological Fluids by Tetrazolate-Functionalized Water-Soluble AIEgens.

The analysis of albumin has clinical significance in diagnostic tests and obvious value to research studies on the albumin-mediated drug delivery and therapeutics. The present immunoassay, instrumental techniques, and colorimetric methods for albumin detection are either expensive, troublesome, or insensitive. Herein, a class of water-soluble tetrazolate-functionalized derivatives with aggregation-induced emission (AIE) characteristics is introduced as novel fluorescent probes for albumin detection. They can be selectively lighted up by site-specific binding with albumin. The resulting albumin fluorescent assay exhibits a low detection limit (0.21 nM), high robustness in aqueous buffer (pH = 6-9), and a broad tunable linear dynamic range (0.02-3000 mg/L) for quantification. The tetrazolate functionality endows the probes with a superior water solubility (>0.01 M) and a high binding affinity to albumin (KD = 0.25 µM). To explore the detection mechanism, three unique polar binding sites on albumin are computationally identified, where the multivalent tetrazolate-lysine interactions contribute to the tight binding and restriction of the molecular motion of the AIE probes. The key role of lysine residues is verified by the detection of poly-l-lysine. Moreover, we applied the fluorogenic method to quantify urinary albumin in clinical samples and found it a feasible and practical strategy for albumin analysis in complex biological fluids.