Facile Construction of Carboxyl-Functionalized Ionic Polymer towards Synergistic Catalytic Cycloaddition of Carbon Dioxide into Cyclic Carbonates.

The development of bifunctional ionic polymers as heterogeneous catalysts for effective, cocatalyst- and metal-free cycloaddition of carbon dioxide into cyclic carbonates has attracted increasing attention. However, facile fabrication of such polymers having high numbers of ionic active sites, suitable types of hydrogen bond donors (HBDs), and controlled spatial positions of dual active sites remains a challenging task. Herein, imidazolium-based ionic polymers with hydroxyl/carboxyl groups and high ionic density were facilely prepared by a one-pot quaternization reaction. Catalytic evaluation demonstrated that the presence of HBDs (hydroxyl or carboxyl) could enhance the catalytic activities of ionic polymers significantly toward the CO2 cycloaddition reaction. Among the prepared catalysts, carboxyl-functionalized ionic polymer (PIMBr-COOH) displayed the highest catalytic activity (94% yield) in the benchmark cycloaddition reaction of CO2 and epichlorohydrin, which was higher than hydroxyl-functionalized ionic polymer (PIMBr-OH, 76% yield), and far exceeded ionic polymer without HBDs groups (PIMBr, 54% yield). Furthermore, PIMBr-COOH demonstrated good recyclability and wide substrate tolerance. Under ambient CO2 pressure, a number of epoxides were smoothly cycloadded into cyclic carbonates. Additionally, density functional theory (DFT) calculation verified the formation of strong hydrogen bonds between epoxide and the HBDs of ionic polymers. Furthermore, a possible mechanism was proposed based on the synergistic effect between carboxyl and Br- functionalities. Thus, a facile, one-pot synthetic strategy for the construction of bifunctional ionic polymers was developed for CO2 fixation.

Systematic review and meta-analysis of the therapeutic effects of minimally invasive transforaminal interbody fusion on spondylolisthesis.

BACKGROUND: Minimally invasive transforaminal interbody fusion (MI-TLIF) can minimize surgical incision, tissue damage, and intraoperative blood loss in the treatment of spondylolisthesis. However, there is a lack of evidence-based research to confirm its clinical efficacy. METHODS: Chinese and English databases were searched with "open", "minimally invasive transforaminal interbody fusion", "MIS-TLIF", "spondylolisthesis", and "open transforaminal interbody fusion" as search terms. Rev Man 5.3 provided by the Cochrane system was used to assess the quality of the literature. RESULTS: Of the 12 randomized controlled trials (RCTs), 7 references were level A (58.34%), 4 were B level (33.33%), and 1 reference was C level (8.33%). There was a statistically significant difference in intraoperative blood loss between MI-TLIF and open transforaminal interbody fusion (O-TLIF) in the treatment of spondylolisthesis [mean difference (MD) =-349.35, 95% confidence interval (CI): (-410.66, -288.03), P<0.00001]. There was also a statistically significant difference in visual analogue scale (VAS) scores before and after MI-TLIF at the last follow-up [MD =5.72, 95% CI: (4.83, 6.62), P<0.00001], and in the complication rate between MI-TLIF and O-TLIF [odds ratio (OR) =0.48, 95% CI: (0.30, 0.76), P<0.00001]. DISCUSSION: This meta-analysis confirmed that MI-TLIF could significantly reduce intraoperative blood loss, mitigate patient pain, and reduce the incidence of complications without increasing the operation time in the treatment of spondylolisthesis.

Visible-light driven photodegradation on Ag nanoparticle-embedded fullerene (C60) heterostructural microcubes.

Three-dimensional Ag(I)-fullerene hybrid microcrystal is fabricated by AgNO3 assisted liquid-liquid interfacial precipitation, containing the abundant sp2-π-electron system. With a mild chemical reduction, it produces the massive Ag nanocluster/fullerene junctions, on which fullerene doubles role as the excellent electron acceptor and photon scavenger, enabling the Plasmon-driven catalytic reaction. Ag nanocluster employed alone could not perform this photocatalytic reaction, neither of fullerene (C60) crystal. It implicates that Ag-fullerene interface is a key to drive catalytic process. Relative to conventional TiO2 nanostructures, fullerene expands light absorption to most solar wavelength and possesses a tightened bandgap which intrinsically expedites the charge transfer and charge separation from coinage metals. Demonstrated by photodegradation of organic molecules, this Ag(I)-fullerene (C60) composite, consisted of a plethora of electron donor-acceptor dyads renders an additional member to photocatalyst family, potentially implemented for photo-electron conversion, water remedy and beyond.

Palladium/phosphorus-functionalized porous organic polymer with tunable surface wettability for water-mediated Suzuki-Miyaura coupling reaction.

A series of phosphorus-functionalized porous organic polymers supported palladium catalysts with tunable surface wettability were successfully prepared using an easy copolymerization and successive immobilization method. The obtained polymers were carefully characterized by many physicochemical methods. Characterization results suggested that the prepared materials featured hierarchically porous structures, high pore volumes, tunable surface wettability and strong electron-donating ability towards palladium species. We demonstrated the use of these solid catalysts for water-mediated Suzuki-Miyaura coupling reactions. It was found that the surface wettability of the prepared catalysts has an important influence on their catalytic activities. The optimal catalyst, which has excellent amphipathicity and relatively high phosphorus concentration, displayed superior catalytic activity compared to the other catalysts. Under ambient conditions, a variety of aryl chlorides can be efficiently transformed to biaryls in high yields. Moreover, the catalyst could be easily recovered and reused at least six times.