Fine metal nanoparticles (2–3 nm; Au, Pt, and alloyed Au–Pt) with a narrow size distribution were deposited on active TiO2 through a facile chemical reduction method. Compared to the bare TiO2, a ...remarkable enhancement of up to 10-fold for photocatalytic hydrogen evolution was achieved on the alloyed nanocomposites. By using core level and valence band XPS analysis, two electronic properties are shown to contribute to the promoted photocatalytic activity: stronger metal–support interaction between the alloyed structures and TiO2 and higher electron population on the Au–Pt/TiO2 photocatalysts in comparison with the bare TiO2. Moreover, an improved charge separation over TiO2 using Au–Pt nanoparticles was clearly evidenced by the significant increase of photocurrent responses obtained from the photoelectrochemical measurements. For the first time, in situ 13C and 1H NMR spectroscopy was applied to monitor the gas–liquid–solid photocatalytic reactions under real working conditions. Via a two-electron oxidation pathway, the surface-adsorbed methanol was first oxidized to formaldehyde, followed by spontaneous hydrolysis and methanolysis to methanediol and methoxymethanol, rather than methyl formate and formic acid that have been previously reported in gaseous CH3OH photocatalysis. The in situ monitoring also revealed that deposition of metal NPs would not alter the reaction pathways while making the reaction faster compared to the bare TiO2.
A green carbon capture and conversion technology offering scalability and economic viability for mitigating CO2 emissions is reported. The technology uses suspensions of gallium liquid metal to ...reduce CO2 into carbonaceous solid products and O2 at near room temperature. The nonpolar nature of the liquid gallium interface allows the solid products to instantaneously exfoliate, hence keeping active sites accessible. The solid co‐contributor of silver–gallium rods ensures a cyclic sustainable process. The overall process relies on mechanical energy as the input, which drives nano‐dimensional triboelectrochemical reactions. When a gallium/silver fluoride mix at 7:1 mass ratio is employed to create the reaction material, 92% efficiency is obtained at a remarkably low input energy of 230 kWh (excluding the energy used for dissolving CO2) for the capture and conversion of a tonne of CO2. This green technology presents an economical solution for CO2 emissions.
With mechanical energy as the stimulus, CO2 is converted into solid carbon and O2 in a liquid‐metal‐based reaction system. Using the synergism of Ga nanodroplets and Ag–Ga nanorods, CO2 conversion proceeds through the triboelectrochemical reaction on Ga, while the Ag–Ga rods ensure the system's sustainability. This is achieved at a remarkably low energy consumption and high efficiency.
Room‐temperature synthesis of 2D graphitic materials (2D‐GMs) remains an elusive aim, especially with electrochemical means. Here, it is shown that liquid metals render this possible as they offer ...catalytic activity and an ultrasmooth templating interface that promotes Frank–van der Merwe regime growth, while allowing facile exfoliation due to the absence of interfacial forces as a nonpolar liquid. The 2D‐GMs are formed at low onset potential and can be in situ doped depending on the choice of organic precursors and the electrochemical set‐up. The materials are tuned to exhibit porous or pinhole‐free morphologies and are engineered for their degree of oxidation and number of layers. The proposed liquid‐metal‐based room‐temperature electrochemical route can be expanded to many other 2D materials.
A liquid metal establishes an ultrasmooth liquid–liquid interface that catalyses the dissociation of organic precursors into interfacial graphitic carbon films. The electrochemical synthesis of these 2D graphitic films is accomplished at room temperature (with only a small energy input, an onset voltage of 0.45 V) and they self‐exfoliate from the nonpolar surface of the liquid metal by applying higher voltages.
The hypercoordinate SiH62− anion is not stable in solution. Here, we report the room temperature, solution stable molecular SiH62− complex, {KCa(NON)(OEt2)}2SiH6 ...(NON=4,5‐bis(2,6‐diisopropylanilido)‐2,7‐di‐tert‐butyl‐9,9‐dimethyl‐xanthene)), where the SiH62− anion is stabilised within a supramolecular assembly that mimics the solid‐state environment of the anion in the lattice of K2SiH6. Solution‐state reactivity of the complex towards carbon monoxide, benzaldehyde, azobenzene and acetonitrile is reported, yielding a range of reduction and C−C coupled products.
Bring solid state chemistry into solution. Using a supramolecular assembly to mimic the coordination environment of SiH62− in the solid‐state, a molecular SiH62− complex that is stable in solution is reported.
Drug checking is a harm reduction measure that provides people with the opportunity to confirm the identity and purity of substances before consumption. The CanTEST Health and Drug Checking Service ...is Australia's first fixed-site drug checking service, where clients can learn about the contents of the samples they provide while receiving tailored harm reduction and health advice. Three samples were recently presented to the service with the expectation of 4-fluoromethylphenidate (4F-MPH) 1, methoxetamine (MXE) 2 and 3-methylmethcathinone (3-MMC) 3. The identity of all three samples did not meet these expectations and remained unknown on-site, as no high confidence identifications were obtained. However, further analysis by nuclear magnetic resonance spectroscopy, high resolution gas chromatography-electron ionisation-mass spectrometry and liquid chromatography-electrospray ionisation-mass spectrometry at the nearby Australian National University allowed for the structure elucidation of the three samples as 4-fluoro-α-pyrrolidinoisohexanophenone (4F-α-PiHP) 4, 1-(4-fluorobenzyl)-4-methylpiperazine (4F-MBZP) 5 and N-propyl-1,2-diphenylethylamine (propylphenidine) 6, respectively. Given all three samples were not of the expected identity and have not yet been described as new psychoactive substances in the literature, this study presents a full characterisation of each compound. As exemplified by this rapid identification of three unexpected new psychoactive substances, drug checking can be used as an effective method to monitor the unregulated drug market.
A “stage-1” intercalated film has been made by the ion exchange of pyrrolidinium-functionalized C60 (C60(Py)n+) into centimeter-wide, micrometer-thick air-dried graphene oxide (G-O) films composed of ...tens of thousands of layers of stacked/overlapping G-O platelets, denoted C60(Py)n+G-O films. Spontaneous intercalation by ion exchange of one layer of C60(Py)n+ between adjacent G-O layers expands the interlayer spacing of the films from 0.74 nm to 1.46 nm. The films remain intact in water and various organic solvents, which is likely due to a strong affinity between C60(Py)n+ and G-O. Membranes made of the films showed a 6.8 times faster water vapor permeation rate (allowing the vapor to transport through the membrane almost freely) and a 10.5 times faster liquid water permeation rate than G-O membranes. Heating the films at 2000 °C under applied pressure or at 2700 °C without physical confinement converted them into highly graphitized structures.
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•A stage-1 intercalation of cationic C60 into graphene oxide films is reported.•Intercalation driven by ion exchange expands the interlayer distance of the films.•Intercalated films remain stable in water and various organic solvents.•Water vapor transports through the intercalated films almost freely.•Heating the film at 2700 °C converted it into highly graphitized structures.
A green carbon capture and conversion technology offering scalability and economic viability for mitigating CO
emissions is reported. The technology uses suspensions of gallium liquid metal to reduce ...CO
into carbonaceous solid products and O
at near room temperature. The nonpolar nature of the liquid gallium interface allows the solid products to instantaneously exfoliate, hence keeping active sites accessible. The solid co-contributor of silver-gallium rods ensures a cyclic sustainable process. The overall process relies on mechanical energy as the input, which drives nano-dimensional triboelectrochemical reactions. When a gallium/silver fluoride mix at 7:1 mass ratio is employed to create the reaction material, 92% efficiency is obtained at a remarkably low input energy of 230 kWh (excluding the energy used for dissolving CO
) for the capture and conversion of a tonne of CO
. This green technology presents an economical solution for CO
emissions.
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The solid state structures of the hexaamine cage complexes M(Me8tricosane)2+ (M = Zn, Cd, Hg) were previously shown to feature highly symmetric octahedral or trigonal prismatic ...coordination geometries. Here we show that the solution NMR spectra of each of these three complexes are far more complex than what would be expected if the solid state structures were retained after dissolution. The large numbers of resonances observed in the solution NMR spectra reflects establishment of equilibria involving multiple diastereoisomers with different nitrogen atom configurations. Support for this explanation was provided by the 15N HSQC spectrum of the Zn complex, and by variable temperature 1H and 13C NMR spectra of each of the three metal complexes. In addition, the results of calculations performed using DFT methods showed that the differences in energy between diastereoisomers were sometimes very small, and therefore unlikely to present a significant barrier to isomerisation processes.
The alkane σ-complex (HEB)W(CO)2(pentane) (HEB = η6-hexaethylbenzene) is produced from the UV photolysis of (HEB)W(CO)3 in alkane solvents at low temperature. IR and 1H and 13C NMR spectroscopic ...data are reported, representing the first NMR data for a goup 6 alkane complex. Only binding of the methyl functionality of the pentane ligand was observed in (HEB)W(CO)2(pentane). This contrasts with the previously reported binding of pentane to rhenium fragments, wherein both methylene and methyl groups were observed to bind, with a slight preference for binding of the former. The reason for the preference for binding through the methyl group is investigated, and the steric requirement for the pentane to adopt an unfavorable gauche conformation when bound via a methylene is identified as a contributing factor.
Alkane complexes of the type Cp‘Re(CO)2(alkane) (Cp‘ = cyclopentadienyl or (isopropyl)cyclopentadienyl; alkane = isotopomers of n-pentane and cyclopentane) have been characterized using NMR ...spectroscopy following photolysis of Cp‘Re(CO)3 in the appropriate alkane at 163−193 K. In the case of n-pentane, three different complexes are observed corresponding to binding of the three different types of carbon in this alkane. ROESY NMR experiments indicate that these isomeric complexes are slowly interconverting intramolecularly at 173 K. The order of the energetically preferred site of coordination is methylene (C2) ≈ central methylene (C3) > methyl (C1) but with a spread of <0.2 kcal mol-1. Isotopic perturbation of resonance (IPR) experiments, conducted on several isotopomers of (i-PrCp)Re(CO)2(1-pentane), showed a large shielding of the 1H NMR chemical shift of the proton in a bound CHD2 moiety (δ −3.62) and CH2D (δ −2.64) compared with that of a bound CH3 moiety (δ −1.99). Likewise, the value of 1 J CH for the coordinated methyl group of isotopomers of (i-PrCp)Re(CO)2(1-pentane) reduces in the order CH3 > CH2D > CHD2. This suggests that the alkane coordinates in an η2-C,H fashion with a rapid exchange of bound hydrogen or deuterium within a methyl or methylene group, and that binding of a hydrogen atom is preferred over a deuterium by an amount of 0.23 ± 0.03 kcal mol-1.
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![Stabilisation of the [SiH6]...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0947-6539/small "Stabilisation of the [SiH6]2− Anion within a Supramolecular Assembly")
