Modulation of Self-Assembly Enhances the Catalytic Activity of Iron Porphyrin for CO2 Reduction.

Electrochemical reduction of CO2 in aqueous media is an important reaction to produce value-added carbon products in an environmentally and economically friendly manner. Various molecule-based catalytic systems for the reaction have been reported thus far. The key features of state-of-the-art catalytic systems in this field can be summarized as follows: 1) an iron-porphyrin-based scaffold as a catalytic center, 2) a dinuclear active center for the efficient activation of a CO2 molecule, and 3) a hydrophobic channel for the accumulation of CO2 . This article reports a novel approach to construct a catalytic system for CO2 reduction with the aforementioned three key substructures. The self-assembly of a newly designed iron-porphyrin complex bearing bulky substituents with noncovalent interaction ability forms a highly ordered crystalline solid with adjacent catalytically active sites and hydrophobic pores. The obtained crystalline solid serves as an electrocatalyst for CO2 reduction in aqueous media. Note that a relevant iron-porphyrin complex without bulky substituents cannot form a porous structure with adjacent active sites, and the catalytic performance of the crystals of this relevant iron-porphyrin complex is substantially lower than that of the newly developed catalytic system. The present study provides a novel strategy for constructing porous crystalline solids for small-molecule conversions.

Ice slurry ingestion during break times attenuates the increase of core temperature in a simulation of physical demand of match-play tennis in the heat.

This investigation assessed the effect of ice slurry ingestion compared to that of cold water ingestion during break times on thermal strain and perception in simulated match-play tennis in the heat. Seven male recreational athletes (age = 22 ± 2 yr, height = 1.72 ± 0.08 m, Body mass = 64.8 ± 6.8 kg) performed two trials in a climate chamber, each time completing 4 sets of simulated match-play. During International Tennis Federation-mandated breaks (90-s between odd-numbered games; 120-s between sets), either ice slurry or cold water were ingested. The rectal temperature, forehead skin temperature, heart rate, rating of thermal comfort and total sweat loss were measured. The change in rectal temperature in the ice slurry trial was significantly lower than that in the cold water trial by game 3 of set 3 (p = 0.02). These differences in Δrectal temperature persisted throughout the remainder of the "match" (p < 0.05). Forehead skin temperature, heart rate and rating of thermal comfort were significantly lower in the ice slurry trial than in the cold water trial by the second half of the experiment (p < 0.05). Total sweat loss in ice slurry trial is significantly lower than cold water trial (p = 0.002). These results suggested that ice slurry ingestion was more effective than cold water ingestion in mitigating the development of heat strain during simulated match-play tennis in the heat.

Chemoselective epoxidation of cholesterol derivatives on a surface-designed molecularly imprinted Ru-porphyrin catalyst.

A new molecularly imprinted Ru-porphyrin complex catalyst on a SiO2 support was designed, prepared, and characterized in a step-by-step manner for the C5[double bond, length as m-dash]C6 epoxidation of cholesterol derivatives. High chemoselectivity for the C5[double bond, length as m-dash]C6 epoxidation of cholesterol derivatives without protecting the 3-position OH group and other oxidizable functional groups was achieved on the molecularly imprinted catalyst.

Preparation and catalytic performance of a molecularly imprinted Pd complex catalyst for Suzuki cross-coupling reactions.

A SiO2-supported molecularly imprinted Pd complex with SiO2-matrix overlayers was prepared as a Suzuki cross-coupling catalyst. A ligand on the supported Pd complex was used as a molecular imprinting template to create the reaction space. The structures of the supported and molecularly imprinted Pd complexes on SiO2 were determined by solid-state MAS 13C, 29Si, and 31P NMR; diffuse reflectance UV/vis; XPS; and Pd K-edge XAFS. The catalytic performance of the molecularly imprinted Pd complex catalyst was very different for various combinations of aryl iodides and arylboronic acids. Reactants with bulky substituent groups were hindered on the imprinted catalyst in Suzuki cross-coupling reactions.