Dual-rotor strategy for organic cocrystals with enhanced near-infrared photothermal conversion.

Organic cocrystal engineering provides a promising route to promote the near-infrared (NIR) light harvesting and photothermal conversion (PTC) abilities of small organic molecules through the rich noncovalent bond interactions of D/A units. Besides, the single-bond rotatable groups known as "rotors" are considered to be conducive to the nonradiative transitions of the excited states of organic molecules. Herein, we propose a single-/double-bond dual-rotor strategy to construct D-A cocrystals for NIR PTC application. The results reveal that the cocrystal exhibits an ultra-broadband absorption from 300 nm to 2000 nm profiting from the strong π-π stacking and charge transfer interactions, and the weakened p-π interaction. More importantly, the PTC efficiency of cocrystals at 1064 nm in the NIR-II region can be largely enhanced by modulating the number of rotor groups and the F-substituents of D/A units. As is revealed by fs-TA spectroscopy, the superior NIR PTC performance can be attributed to the nonradiative decays of excited states induced by the free rotation of the single-bond rotor (-CH3) from the donors and the inactive double-bond rotor ([double bond, length as m-dash]C(C[triple bond, length as m-dash]N)2) being in the active form of [-C(C[triple bond, length as m-dash]N)2] in the excited states from the acceptors. This prototype displays a promising route to extend the functionalization of small organic molecules based on organic cocrystal engineering.

Mechanochemistry toward Organic "Salt" via Integer-Charge-Transfer Cocrystal Strategy for Rapid, Efficient, and Scalable Near-Infrared Photothermal Conversion.

Invited for this month's cover is the group of Shun-Li Chen and Ming-De Li at the Shantou University. The image shows that one electron can be transferred easily from donor to acceptor unit to obtain integer-charge-transfer cocrystals for realizing high-efficient solar-harvesting and photothermal conversion. The Research Article itself is available at 10.1002/cssc.202300644.

Mechanochemistry toward Organic "Salt" via Integer-Charge-Transfer Cocrystal Strategy for Rapid, Efficient, and Scalable Near-Infrared Photothermal Conversion.

Inspired by the concept of ionic charge-transfer complexes for the Mott insulator, integer-charge-transfer (integer-CT) cocrystals are designed for NIR photo-thermal conversion (PTC). With amino-styryl-pyridinium dyes and F4TCNQ (7,7',8,8'-Tetracyano-2,3,5,6-tetrafluoroquinodimethane) serving as donor/acceptor (D/A) units, integer-CT cocrystals, including amorphous stacking "salt" and segregated stacking "ionic crystal", are synthesized by mechanochemistry and solution method, respectively. Surprisingly, the integer-CT cocrystals are self-assembled only through multiple D-A hydrogen bonds (C-H⋅⋅⋅X (X=N, F)). Strong charge-transfer interactions in cocrystals contribute to the strong light-harvesting ability at 200-1500 nm. Under 808 nm laser illumination, both the "salt" and "ionic crystal" display excellent PTC efficiency beneficial from ultrafast (∼2 ps) nonradiative decay of excited states. Thus integer-CT cocrystals are potential candidates for rapid, efficient, and scalable PTC platforms. Especially amorphous "salt" with good photo/thermal stability is highly desirable in practical large-scale solar-harvesting/conversion applications in water environment. This work verifies the validity of the integer-CT cocrystal strategy, and charts a promising path to synthesize amorphous PTC materials by mechanochemical method in one-step.

Organic Photothermal Cocrystals: Rational Design, Controlled Synthesis, and Advanced Application.

Organic photothermal cocrystals, integrating the advantages of intrinsic organic cocrystals and the fascinating photothermal conversion ability, hold attracted considerable interest in both basic science and practical applications, involving photoacoustic imaging, seawater desalination, and photothermal therapy, and so on. However, these organic photothermal cocrystals currently suffer individual cases discovered step by step, as well as the deep and systemic investigation in the corresponding photothermal conversion mechanisms is rarely carried out, suggesting a huge challenge for their further developments. Therefore, it is urgently necessary to investigate and explore the rational design and synthesis of high-performance organic photothermal cocrystals for future applications. This review first and systematically summarizes the organic photothermal cocrystal in terms of molecular classification, the photothermal conversion mechanism, and their corresponding applications. The timely interpretation of the cocrystal photothermal effect will provide broad prospects for the purposeful fabrication of excellent organic photothermal cocrystals toward great efficiency, low cost, and multifunctionality.

Boosting Near-Infrared Photothermal Conversion by Intermolecular Interactions in Isomeric Cocrystals.

Organic cocrystal exhibits excellent photothermal conversion (PTC), but how the intermolecular interactions of cocrystals regulate the PTC is obscure. Here, two isomeric donor molecules (phenanthrene and anthracene) and two electron-withdrawing molecules (7,7,8,8,8-tetracyanodimethylquinone and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinone dimethane) are self-assembled into the four cocrystals (PTQ, PFQ, ATQ, and AFQ). By changing the molecular configuration of the donor and the electron-withdrawing ability of the acceptor, the intrinsic influencing factors of the intermolecular interaction on the PTC were explored. Under near-infrared laser (808 nm) irradiation, the PTC efficiencies of PTQ, PFQ, AFQ, and ATQ are 35.85, 44.74, 57.00, and 60.53%, respectively. Based on the single-crystal X-ray diffraction, ultrafast time-resolved transient absorption, and excited-state theoretical calculations, we found that the π-π stacking in ATQ and AFQ is conducive to promoting the near-infrared light-harvesting ability and the p-π interaction of cocrystals can regulate the nonradiative rotation of -C(C≡N)2 groups, resulting in a tunable near-infrared PTC via the isomeric cocrystals. Accordingly, the evaporation rate of the porous polyurethane-AFQ foam can reach 1.33 kg·m-2·h-1 in the simulated solar-driven water evaporation system. This work provides a strategy to boost the PTC by the intermolecular interactions of cocrystal materials.

Segregated Array Tailoring Charge-Transfer Degree of Organic Cocrystal for the Efficient Near-Infrared Emission beyond 760 nm.

Harvesting the narrow bandgap excitons of charge-transfer (CT) complexes for the achievement of near-infrared (NIR) emission has attracted intensive attention for its fundamental importance and practical application. Herein, the triphenylene (TP)-2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4 TCNQ) CT organic complex is designed and fabricated via the supramolecular self-assembly process, which demonstrates the NIR emission with a maximum peak of 770 nm and a photoluminescence quantum yield (PLQY) of 5.4%. The segregated stacking mode of TP-F4 TCNQ CT complex based on the multiple types of intermolecular interaction has a low CT degree of 0.00103 and a small counter pitch angle of 40° between F4 TCNQ and TP molecules, which breaks the forbidden electronic transitions of CT state, resulting in the effective NIR emission. Acting as the promising candidates for the active optical waveguide in the NIR region beyond 760 nm, the self-assembled TP-F4 TCNQ single-crystalline organic microwires display an ultralow optical-loss coefficient of 0.060 dB µm-1 . This work holds considerable insights for the exploration of novel NIR-emissive organic materials via an universal "cocrystal engineering" strategy.

[Protective effect of total triterpenoids from Chaenomeles speciosa against Helicobacter pylori-induced gastritis in mice].

This study investigated the protective effect of total triterpenoids from Chaenomeles speciosa against Helicobacter pylori(Hp)-induced gastritis in mice and explored its possible mechanism. The chronic atrophic gastritis(CAG) model mice were randomly divided into four groups of model, total triterpenoids from C. speciosa(50 and 100 mg·kg~(-1)) and triple therapy, with C57 BL/6 J mice without Hp infection taken as the normal group. Mice in the treatment groups were given corresponding drugs once a day for 4 weeks. Then the following indexes were detected: the contents of reactive oxygen species(ROS), monocyte chemotactic protein 1(MCP-1), keratinocyte chemokines(KC), TNF-α, IL-1ß, IL-6, IL-18, IL-4 and IL-10 in blood and gastric tissue, the activities and contents of LDH, MPO, SOD, GSH-Px, CAT and MDA in gastric tissue and the activities of ß-glucuronidase, ß-galactosidase, cathepsins B and D in blood, gastric tissue and lysosome. Besides, the mRNA expression levels of Toll-like receptor 4(TLR4), myeloid differentiation factor 88(MyD88), Bcl-2, Bcl-xl, Bax and Bad in gastric tissue were determined by quantitative real-time PCR. Western blot was employed to detect the protein expression levels of TLR4, MyD88, p-IKKß, p-IκBα, NOD-like receptor 3(NLRP3), apoptosis-associated speck-like protein(ASC), pro-caspase-1, caspase-1, thioredoxin-interacting protein(TXNIP), pro-IL-1ß, pro-IL-18, Bcl-2, Bcl-xl, Bax, Bad, cytochrome C, apoptotic protease-activating factor-1(Apaf-1), pro-caspase-9, pro-caspase-3, cleaved-caspase-9, cleaved-caspase-3, poly(ADP-ribose) polymerase 1(PARP-1), cleaved-PARP-1 and cytosol and nucleus NF-κB p65 in gastric tissue. The results indicated that the total triterpenoids from C. speciosa significantly suppressed Hp proliferation, alleviated the damage to gastric mucosa and improved lymphocyte infiltration and gland atrophy. They were also effective in reducing the activities of ß-glucuronidase, ß-galactosidase, cathepsins B and D in blood and gastric tissue, elevating the activities of ß-glucuronidase and cathepsin D in lysosomal organelles, decreasing the contents of ROS, MCP-1, KC, TNF-α, IL-1ß, IL-6, IL-18 in blood, MDA content and MPO and LDH activities in gastric tissue and increasing the contents of IL-4 and IL-10 in blood and activities of SOD, CAT and GSH-Px in gastric tissue. Other phenomena were also observed after the treatment with total triterpenoids from C. speciosa, including the down-regulation of the mRNA and protein expression levels of TLR4, MyD88, Bax and Bad, the protein expression levels of p-IKKß, p-IκBα, NLRP3, ASC, pro-caspase-1, caspase-1, TXNIP, pro-IL-1ß, pro-IL-18, cytochrome C, Apaf-1, cleaved-caspase-9, cleaved-caspase-3, cleaved-PARP-1 and nuclear NF-κB p65, reduction of p-IKKß/IKKß and p-IκBα/IκBα ratios and up-regulation of the mRNA and protein expression levels of Bcl-2 and Bcl-xl, up-regulation of pro-caspase-9, pro-caspace-3, cytosol NF-κB p65 protein expression levels and Bcl-2/Bax and Bcl-xl/Bad ratios in gastric tissue. These aforementioned results suggest that the total triterpenoids from C. speciosa have significant protective effects against CAG induced by Hp, and its mechanism may be related to enhancing the function of endogenous antioxidant system, suppressing the oxidative stress and inflammatory reaction induced by Hp, correcting lysosomal dysfunction and inflammatory activation of TLR4/NF-κB/NLRP3 inflammasome signaling pathway and thus inhibiting mitochondria-mediated apoptosis.

The use of topical intranasal fluorescein in endoscopic endonasal repair of cerebrospinal fluid rhinorrhea.

BACKGROUND: The CSF rhinorrhea is a kind of common clinical disease. The preoperative diagnosis and intraoperative localization of CSF fistulas are critical to treatment of CSF rhinorrhea. At present, intrathecal fluorescein regarding endoscopic transnasal cerebrospinal leakage repair is a common method for localization of the fistula; however, it has some disadvantages because it needs a specific endoscope, and the trauma from lumbar puncture as well as the potential complications of intrathecal fluorescein, as a result, widely limited its clinical use. Topical intranasal fluorescein can avoid the above-mentioned shortcoming. The aim of this work was to describe the use of topical fluorescein in the intraoperative localization of CSF fistulas and to screen its use in preoperative diagnosis of CSF rhinorrhea. METHODS: Fifteen patients with CSF rhinorrhea were treated with an endoscopic endonasal technique. Topical intranasal 5% fluorescein for preoperative diagnosis and intraoperative localization of the site of the leak was placed in middle turbinate meatus, the roof of the ethmoid plate, and sphenoethmoidal recesses. A change in the color of the fluorescein from brown to green fluorescence denoted the presence of CSF, and the site of the leak could be traced. The accuracy rate of diagnosis and leak site identification was made by comparison with glucose analysis, intraoperative findings, and follow-up. RESULTS: The cause of the leak was accidental trauma in 5 patients and spontaneous in 10 patients. The preoperative use of fluorescein-soaked cotton was 100% accurate in diagnosing CSF rhinorrhea. The intraoperative use of topical intranasal fluorescein was also 100% accurate in locating the site of the CSF fistula when compared with the surgical findings. It had achieved 100% success rate in sealing the CSF fistulas in our 15 patients with no recurrence detected during the follow-up period (mean, 2-24 months). No complications have been reported. CONCLUSION: In the presence of a clinically diagnosed CSF leakage and location of the leakage fistula, topical fluorescein is a very easy, sensitive, safe, and highly accurate tool in the intraoperative localization of the site and extent of CSF fistulas. It should be considered as a viable noninvasive alternative to intrathecal fluorescein.

[Application of topical intranasal fluorescein in endoscopic endonasal repair of cerebrospinal fluid leakage].

OBJECTIVE: To investigate the effects of topical fluorescein on the preoperative diagnosis of rhinorrhea of cerebrospinal fluid (CSF) and intraoperative localization of CSF fistula. METHODS: Cotton pads soaked with 5% fluorescein were placed in the middle turbinate meatus, roof of ethmoid plate, and sphenoethmoidalis recesses via endoscopic endonasal technique of 15 patients with CSF rhinorrhea, 5 caused by accidental trauma and 10 spontaneous. Change of the color of fluorescein from yellow to green fluorescence denoted the presence of CSF, and thus the site of the leak could be traced. The accuracy rates of diagnosis and leak site identification by this technique were compared with those by glucose analysis, intraoperative findings, and follow-up. RESULTS: The preoperative diagnosis rate of CSF rhinorrhea and the CSF fistula site localization rate by fluorescein-soaked cotton pad were both 100%. No recurrence was found during the follow-up for 2 - 24 months. No complication had been reported. CONCLUSIONS: Application of topical fluorescein is an easy, sensitive, safe, and highly accurate tool in the intraoperative localization of the site and extent of CSF fistulas and should be considered a viable noninvasive alternative to intrathecal fluorescein technique.