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) approximately 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 (delta -3.62) and CH2D (delta -2.64) compared with that of a bound CH3 moiety (delta -1.99). Likewise, the value of 1JCH 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 eta2-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.

2-3 nmfine metal nanoparticles (Au, Pt and alloyed Au-Pt) with a narrow size distribution were deposited on active TiO 2 through a facile chemical reduction method.Compared to the bare TiO 2 , a remarkable enhancement of up to 10-fold for photocatalytichydrogen evolutionwas 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 TiO 2 and higher electron population on the Au-Pt/TiO 2 photocatalysts in comparison with thebare TiO 2 . Moreover, an improved charge separation over TiO 2 usingAuPt nanoparticles was clearly evidenced by the significant increase of photocurrent responses obtained from the photoelectrochemical measurements.For the first time, in situ 13 C and 1 HNMR spectroscopy was applied to monitor the gas-liquid-solid photocatalytic reactionsunder real working conditions. Via a two-electron oxidation pathway, the surfaceadsorbed methanol was firstly 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 CH 3 OH photocatalysis. The in situ monitoring also revealed that deposition of metal NPs would not alter the reaction pathways whilemaking the reaction faster compared to the bare TiO 2 .

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.

(10 of 11)www.advmat.de www.advancedsciencenews.com steps in the pre-edge region of the XAS spectra (10 167-10 347 eV), 0.25 eV steps in the XANES region (10 347-10 417 eV). In the extended X-ray absorption fine structure region spectra were collected, in steps of 0.035k to a maximum of 10k, with count time increasing linearly from 2 up to 4 s at the end of the energy range. Multiple scans were collected for each sample. Data were preprocessed using Sakura (in-house program) and the Athena program for scan averaging, background subtraction, and edge-height normalization (Ravel and Newville, 2005). Periodically throughout the experiment, transmission scans were collected of the in-line Re foil.

Which bonds bind better? According to NMR experiments with the alkane complex [CpRe(CO)2(cyclohexane)] at low temperatures, complexation with an axial proton is preferred over that through an equatorial one by about 1.5 kJ mol−1. Calculations support this order of binding energies. The preference is proposed to be due to stronger electron donation through hyperconjugation from a CH bond than from a CC bond.