Solid‐State Structure of Protonated Ketones and Aldehydes

Protonated carbonyl compounds have been invoked as intermediates in many acid‐catalyzed organic reactions. To gain key structural and electronic data about such intermediates, oxonium salts derived from five representative examples of ketones and aldehydes are synthesized in the solid state, and characterized by X‐ray crystallography and Raman spectroscopy for the first time. DFT calculations were carried out on the cations in the gas phase. Whereas an equimolar reaction of the carbonyl compounds, acetone, cyclopentanone, adamantanone, and acetaldehyde, with SbF₅ in anhydrous HF yielded mononuclear oxonium cations, the same stoichiometry in a reaction with benzaldehyde resulted in formation of a hemiprotonated, hydrogen‐bridged dimeric cation. Hemiprotonated acetaldehyde was obtained when a 2:1 ratio of aldehyde and SbF₅ was used. Experimental and NBO analyses quantify the significant increase in electrophilicity of the oxonium cations compared to that of the parent ketones/aldehydes.     

Porous CuxCoyS Supraparticles for In Vivo Telomerase Imaging and Reactive Oxygen Species Generation

In this study, we successfully synthesized Cu_xCo_yS supraparticles (SPs) on the nanoscale featuring multiple pores inside and strong absorption from 400 to 900 nm. Porous Cu_xCo_yS SPs produced the highest reactive oxygen species (ROS) yield (1.39) when illuminated with near‐infrared (NIR) light. Furthermore, we demonstrated that Cu_xCo_yS SPs could be used to identify cancer cells through intracellular telomerase‐responsive fluorescence (FL) imaging in living cells. Because the Cu_xCo_yS SPs were associated with telomerase‐responsive bioimaging and high ROS production, they can be efficiently used in the diagnosis and therapy of tumors with high selectivity and excellent therapeutic effects in vivo. This study provides a new vision for the creation of multifunctional SPs, which can be used as cellular sensors and control tools for pathologies across a broad range of biological systems.     

In Situ Synchrotron X‐ray Characterization Shining Light on the Nucleation and Growth Kinetics of Colloidal Nanoparticles

Rational synthesis of colloidal nanoparticles with desirable properties relies on precise control over the nucleation and growth kinetics, which is still not well understood. The recent development of in situ high energy synchrotron X‐ray techniques offers an excellent opportunity to quantitatively monitor the growth trajectories of colloidal nanoparticles in real time under real reaction conditions. The time‐resolved, quantitative data of the growing colloidal nanoparticles are unique to reveal the mechanism of nanoparticle formation and determine the corresponding intrinsic kinetic parameters. This review discusses the kinetics of major steps of forming colloidal nanoparticles and the capability of in situ synchrotron X‐ray techniques in studying the corresponding kinetics.     

Ferrocene‐Linkage‐Facilitated Charge Separation in Conjugated Microporous Polymers

Conjugated microporous polymers (CMPs) have full access to the organic synthesis toolbox and feature‐rich functionality, structural diversity, and high surface area. We incorporated ferrocene (Fc) into the backbones of CMPs and systematically engineered their optical energy gaps. Compared with the CMPs without Fc units yet adopting a similar molecular orbital level, Fc‐based CMPs can sufficiently generate reactive oxygen species (ROS) under visible light. The resultant ROS are able to effectively decompose the absorbed pollutants, including organic dyes and chemical warfare agents. Specifically, Fc‐based CMPs significantly outperform commercial TiO₂ (P25) in the degradation of methylene blue and are capable of converting 2‐chloroethyl ethyl sulfide (a mustard gas simulant) into a completely nontoxic product.     

Direct Production of Higher Oxygenates by Syngas Conversion over a Multifunctional Catalyst

Selective synthesis of higher oxygenates (linear α‐alcohols and α‐aldehydes, C OH) from syngas is highly attractive but remains challenging owing to the low C OH selectivity and low catalytic stability. Herein we introduce a multifunctional catalyst composed of CoMn and CuZnAlZr oxides that dramatically increased the oxygenates selectivity to 58.1 wt %, where more than 92.0 wt % of the produced oxygenates are C OH. Notably, the total selectivity to value‐added chemicals including oxygenates and olefins reached 80.6 wt % at CO conversion of 29.0 % with high stability. The appropriate component proximity can effectively suppress the formation of the undesired C1 products, and the selectively propulsion of reaction network by synergetic effect of different components contributes to the enhanced selectivity to higher oxygenates. This work provides an alternative strategy for the rational design of new catalysts for direct conversion of syngas into higher oxygenates with co‐production of olefins.     

Evidence of Structure Sensitivity in the Fischer–Tropsch Reaction on Model Cobalt Nanoparticles by Time‐Resolved Chemical Transient Kinetics

The Fischer–Tropsch process, or the catalytic hydrogenation of carbon monoxide (CO), produces long chain hydrocarbons and offers an alternative to the use of crude oil for chemical feedstocks. The observed size dependence of cobalt (Co) catalysts for the Fischer–Tropsch reaction was studied with colloidally prepared Co nanoparticles and a chemical transient kinetics reactor capable of measurements under non‐steady‐state conditions. Co nanoparticles of 4.3 nm and 9.5 nm diameters were synthesized and tested under atmospheric pressure conditions and H₂/CO=2. Large differences in carbon coverage (Θ_C) were observed for the two catalysts: the 4.3 nm Co catalyst has a Θ_C less than one while the 9.5 nm Co catalyst supports a Θ_C greater than two. The monomer units present on the surface during reaction are identified as single carbon species for both sizes of Co nanoparticles, and the major CO dissociation site is identified as the B₅‐B geometry. The difference in activity of Co nanoparticles was found to be a result of the structure sensitivity caused by the loss of these specific types of sites at smaller nanoparticle sizes.