{V6 } Ring Sandwiched Polyoxoniobate as Molecular Electrocatalyst for Oxidant-Free Synthesis of Sulfoxides.

Electrocatalytic oxidation of organic molecules to value-added chemicals has attracted recent attention. Although a series of transition metal based electrocatalytic materials have been developed, the lack of precise structure information generates great challenges in understanding the catalytic mechanism at a molecular level. Herein, we present the synthesis and characterization of a molecular electrocatalyst, Na2 K6 H14 [(VO)6 (α-TeNb9 O33 )2 ] ⋅ 31H2 O ⋅ 2.5 C2 H8 N2 (abbreviated as V6 (TeNb9 )2 ), where a reduced {V6 } ring is sandwiched by two trivacant Keggin-type {α-TeNb9 O33 }. V6 (TeNb9 )2 as heterogeneous electrocatalyst can selectively convert 95 % of thioanisole to sulfoxide with the Faraday efficiency up to 98 %. Notably, the important role of the embedded {V6 } ring in the electrocatalytic oxidation was illustrated by comparing with {Nb6 } ring sandwiched catalyst, Na5 K7 H4 [(NbO)6 (α-TeNb9 O33 )2 ] ⋅ 17H2 O (abbreviated as Nb6 (TeNb9 )2 ). Mechanism studies reveal that during the electrocatalytic oxidation process water is the only oxygen source and a key intermediate PhCH3 S+ ⋅ is involved.

In vivo evaluation of intravascular lithotripsy in a healthy porcine coronary model.

OBJECTIVES: In this study, we aimed to investigate the vascular response to an intravascular lithotripsy (IVL) shockwave balloon in a healthy porcine coronary artery model. BACKGROUND: IVL is a novel clinical technique for modifying heavily calcified atherosclerotic plaques. METHODS: A total of 24 porcine coronary arteries were treated with IVL or plain old balloon angioplasty (POBA). Histology, histomorphometry, quantitative coronary angiography analysis (QCA), and optical coherence tomography (OCT) were performed postprocedure and at 1-month follow-up (1M-FU). RESULTS: There was no significant difference in the late lumen loss and diameter stenosis (determined by QCA) and the minimal lumen area (evaluated by OCT) of the IVL and POBA groups at 1M-FU. Pathological analysis revealed that the lumen and neointima areas were similar between the two groups. However, the medial and adventitial layers were more prominent in the IVL than in the POBA group. The injury score and inflammation of the media and adventitia increased dramatically in the IVL group postprocedure and at 1M-FU. At 1M-FU, media fibrin deposition and adventitial fibrosis were also significantly increased in the IVL group. However, there was no significant difference in neointima fibrin deposition, endothelialization, and thrombosis between both groups. Layered separation of the media and adventitia was observed in the IVL group. CONCLUSION: The findings indicate that the IVL balloon did not cause serious intimal hyperplasia and endothelial damage compared with the effects of POBA in the healthy coronary artery. However, shock waves may cause unique damage to the vascular media and adventitia in the coronary artery, which was not observed in the peripheral artery.

Controllable Assembly of Vanadium-Containing Polyoxoniobate-Based Materials and Their Electrocatalytic Activity for Selective Benzyl Alcohol Oxidation.

During the controllable synthesis of two vanadium-containing Keggin-type polyoxoniobates (PONbs), [Ni(en)2]5[PNb12O40(VO)5](OH)5·18H2O (1) and [Ni(en)3]5[PNb12O40(VO)2]∙17H2O (2, en = ethylenediamine) are realized by changing the vanadium source and hydrothermal temperature. Compounds 1 and 2 have been thoroughly characterized by single-crystal X-ray diffraction analysis, FT-IR spectra, X-ray photoelectron spectrum (XPS), powder X-ray diffraction (PXRD), etc. Compound 1 contains a penta-capped Keggin-type polyoxoniobate {PNb12O40(VO)5}, which is connected by adjacent [Ni(en)2]2+ units into a three-dimensional (3D) organic-inorganic framework, representing the first nickel complexes connected vanadoniobate-based 3D material. Compound 2 is a discrete di-capped Keggin-type polyoxoniobate {PNb12O40(VO)2} with [Ni(en)3]2+ units as counter cations. Compounds 1 and 2 have poor solubility in common solvents and can keep stable in the pH range of 4 to 14. Notably, both 1 and 2 as electrode materials are active for the selective oxidation of benzyl alcohol to benzaldehyde. Under ambient conditions without adding an alkaline additive, compound 1 as a noble metal free electrocatalyst can achieve 92% conversion of benzyl alcohol, giving a Faraday efficiency of 93%; comparatively, 2 converted 79% of the substrate with a Faraday efficiency of 84%. The control experiments indicate that both the alkaline polyoxoniobate cluster and the capped vanadium atoms play an important role during the electrocatalytic oxidation process.

Electrocatalytic ethylbenzene valorization using a polyoxometalate@covalent triazine framework with water as the oxygen source.

Ethylbenzene (EB) oxidation is an important transformation in the chemical industry. Herein, PMo10V2@CTF, a noble metal free electrocatalyst, was used to promote the oxidative upgrading of EB. Under ambient conditions, 65% of EB was converted to three value-added products using water as the oxygen source yielding a total Faraday efficiency of 90.4%. This excellent performance is ascribed to the homogeneous dispersion of PMo10V2 and its dual role in the electrocatalytic process.

Reduced polyoxomolybdate immobilized on reduced graphene oxide for rapid catalytic decontamination of a sulfur mustard simulant.

Keggin-type polyoxometalates (POMs) were immobilized on poly(diallyldimethylammonium chloride) (PDDA) functionalized reduced graphene oxide (rGO) by a facile and broad-spectrum hydrothermal method. The prepared POMs@PDDA-rGO composites (POM = H3PMo12O40, H3PW12O40, H5PMo10V2O40) have been thoroughly characterized using a series of techniques. The three composites can catalyze the oxidative decontamination of a sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES) in the order of PMo12@PDDA-rGO > PMo10V2@PDDA-rGO > PW12@PDDA-rGO. Notably, under ambient conditions PMo12@PDDA-rGO can convert 99% of CEES within 30 min in the presence of nearly stoichiometric aqueous H2O2 (3 wt%) and its catalytic activity is significantly higher than that of homogeneous H3PMo12O40. XPS spectral analysis and control experiments indicate that the Mo center of POM is reduced from +6 to +5 during the hydrothermal process, and the excellent catalytic performance is related to the reduction of Mo. Moreover, the PMo12@PDDA-rGO composite is stable during the decontamination process and it can be used for at least five cycles without loss of activity.

Polyoxometalates encapsulated into hollow double-shelled nanospheres as amphiphilic nanoreactors for an effective oxidative desulfurization.

Although some catalytic hollow nanoreactors have been fabricated in the past, the encapsulated active species focus on metal nanoparticles, and a method for polyoxometalate (POM)-containing hollow nanoreactors has seldom been developed. Herein, we report a synthetic strategy towards POM-based amphiphilic nanoreactors, where the hollow mesoporous double-shelled SiO2@C nanospheres were used to encapsulate Keggin-type H3PMo12O40 (PMo12). The outer hydrophobic carbon shell was beneficial for the enrichment of the organic substrate around the nanoreactor and simultaneously prevented the deposition of POMs on the outer surface of the nanoreactor. The inner hydrophilic silica cavity was modified by two types of organosilanes, which not only created an amphiphilic cavity environment but also acted as an anchor to mobilize PMo12. As the POM nanoreactor had the hydrophilic@hydrophobic SiO2@C shell and an amphiphilic cavity, both dibenzothiophene (DBT) and H2O2 could smoothly diffuse into the nanosized cavity, where the DBT was effectively oxidized (conversion: >99%) by the immobilized PMo12 under mild conditions. Importantly, the control experiments indicated that the confined effect of nanoreactor, amphiphilic SiO2@C double-shell, unique cavity environment, and mesoporous channels accounted for an excellent catalytic performance. Moreover, the nanoreactor was robust and could be reused for five cycles without loss of activity.

Antinociceptive effects of sinomenine in a rat model of postoperative pain.

BACKGROUND AND PURPOSE: This study examined the antinociceptive effects of sinomenine in a rat model of postoperative pain. EXPERIMENTAL APPROACH: Male and female rats were subjected to a surgical incision in the right hind paw, and the von Frey filament test was used to measure mechanical hypersensitivity after drug or vehicle treatment (p.o. or i.p.). Rats were treated daily with sinomenine before or after the surgery and the AUCs of the antinociceptive effects measured during a 4 h period were calculated to determine the ED50 values of sinomenine. The anti-hyperalgesic effects of different doses of a combination of sinomenine and acetaminophen (paracetamol) were assessed in another group of rats. Dose combinations were determined by using a fixed ratio dose-addition analysis method. KEY RESULTS: Sinomenine (5-80 mg·kg(-1) ) produced dose-dependent antinociceptive effects in rats that had been subjected to surgery and this effect lasted for 4 h. The potency of sinomenine, given i.p. or p.o., did not differ between male and female rats. However, sinomenine was fourfold more potent when given i.p. than p.o. The GABAA receptor antagonist bicuculline blocked the antinociceptive effects of sinomenine. The antinociceptive effect of a daily treatment with sinomenine remained stable throughout the course of postoperative pain. Pretreatment with sinomenine did not alter the mechanical hypersensitivity post-surgery. The combination of sinomenine with acetaminophen produced an infra-additive interaction. CONCLUSIONS AND IMPLICATIONS: Sinomenine demonstrated significant antinociceptive activity against postoperative pain and may be a useful novel pharmacotherapy for the management of postoperative pain.

Antinociceptive effects of vitexin in a mouse model of postoperative pain.

Vitexin, a C-glycosylated flavone present in several medicinal herbs, has showed various pharmacological activities including antinociception. The present study investigated the antinociceptive effects of vitexin in a mouse model of postoperative pain. This model was prepared by making a surgical incision on the right hindpaw and von Frey filament test was used to assess mechanical hyperalgesia. Isobolographical analysis method was used to examine the interaction between vitexin and acetaminophen. A reliable mechanical hyperalgesia was observed at 2 h post-surgery and lasted for 4 days. Acute vitexin administration (3-10 mg/kg, i.p.) dose-dependently relieved this hyperalgesia, which was also observed from 1 to 3 days post-surgery during repeated daily treatment. However, repeated vitexin administration prior to surgery had no preventive value. The 10 mg/kg vitexin-induced antinociception was blocked by the opioid receptor antagonist naltrexone or the GABAA receptor antagonist bicuculline. The doses of vitexin used did not significantly suppress the locomotor activity. In addition, the combination of vitexin and acetaminophen produced an infra-additive effect in postoperative pain. Together, though vitexin-acetaminophen combination may not be useful for treating postoperative pain, vitexin exerts behaviorally-specific antinociception against postoperative pain mediated through opioid receptors and GABAA receptors, suggesting that vitexin may be useful for the control of postoperative pain.