Spectroscopic Characterization, Computational Investigation, and Comparisons of ECX

Three newly synthesized [Na+(221-Kryptofix)] salts containing AsCO–, PCO–, and PCS– anions were successfully electrosprayed into a vacuum, and these three ECX– anions were investigated by negative ion photoelectron spectroscopy (NIPES) along with high-resolution photoelectron imaging spectroscopy. For each ECX– anion, a well-resolved NIPE spectrum was obtained, in which every major peak is split into a doublet. The splittings are attributed to spin–orbit coupling (SOC) in the ECX• radicals. Vibrational progressions in the NIPE spectra of ECX– were assigned to the symmetric and the antisymmetric stretching modes in ECX• radicals. The electron affinities (EAs) and SO splittings of ECX• are determined from the NIPE spectra to be AsCO•: EA = 2.414 ± 0.002 eV, SO splitting = 988 cm–1; PCO•: EA = 2.670 ± 0.005 eV, SO splitting = 175 cm–1; PCS•: EA = 2.850 ± 0.005 eV, SO splitting = 300 cm–1. Calculations using the B3LYP, CASPT2, and CCSD(T) methods all predict linear geometries for both the anions and the neutral radicals. The calculated EAs and SO splittings for ECX• are in excellent agreement with the experimentally measured values. The simulated NIPE spectra, which are based on the calculated Franck–Condon factors, and the SO splittings nicely reproduce all of the observed spectral peaks, thus allowing unambiguous spectral assignments. The finding that PCS• has the greatest EA of the three triatomic molecules considered here is counterintuitive based upon simple electronegativity considerations, but this finding is understandable in terms of the movement of electron density from phosphorus in the HOMO of PCO– to sulfur in the HOMO of PCS–. Comparisons of the EAs of PCO• and PCS• with the previously measured EA values for NCO• and NCS• are made and discussed.National Science Foundation (U.S.) (Grant CHE-1362118

In Situ Formed “Sn1–XInX@In1–YSnYOZ” Core@Shell Nanoparticles as Electrocatalysts for CO2 Reduction to Formate

Electrochemical reduction of CO2 (CO2RR) driven by renewable energy has gained increasing attention for sustainable production of chemicals and fuels. Catalyst design to overcome large overpotentials and poor product selectivity remains however challenging. Sn/SnOx and In/InOx composites have been reported active for CO2RR with high selectivity toward formate formation. In this work, the CO2RR activity and selectivity of metal/metal oxide composite nanoparticles formed by in situ reduction of bimetallic amorphous SnInOx thin films are investigated. It is shown that during CO2RR the amorphous SnInOx pre‐catalyst thin films are reduced in situ into Sn1–XInX@In1–YSnYOz core@shell nanoparticles composed of Sn‐rich SnIn alloy nanocores (with x < 0.2) surrounded by InOx‐rich bimetallic InSnOx shells (with 0.3 < y < 0.4 and z ≈ 1). The in situ formed particles catalyze the CO2RR to formate with high faradaic efficiency (80%) and outstanding formate mass activity (437 A gIn+Sn−1 @ −1.0 V vs RHE in 0.1 m KHCO3). While extensive structural investigation during CO2RR reveals pronounced dynamics in terms of particle size, the core@shell structure is observed for the different electrolysis conditions essayed, with high surface oxide contents favoring formate over hydrogen selectivity.DFG, 53182490, EXC 314: Unifying Concepts in CatalysisBMBF, 03X5524, EDELKAT - Hydrophobe Nanoreaktor Templatierung - Eine Tool-Box für optimierte ElektrokatalysatorenBMBF, 01FP13033F, Förderung der Vorgriffsprofessur im Fach "Anorganische Funktionsmaterialien" im Rahmen des Professorinnenprogramms II an der Albert-Ludwigs-Universität FreiburgEC/H2020/101006701/EU/Renewable Electricity-based, cyclic and economic production of Fuel/EcoFue

Screening of Heterogeneous Photocatalysts for Water Splitting

In this contribution, a simple method for the screening of photocatalytic activity of catalyst materials is presented. The method is based on two steps the immobilization of the photocatalyst and the subsequent testing of their photocatalytic activity, using the gas evolution at the solid liquid interface. Up to four catalysts can be tested under the same conditions. The observed gas evolution for selected photocatalysts is consistent with trends reported in the literature from conventional photocatalytic reactor

Addition polymerization of 1,1-dimesitylneopentylgermene: synthesis of a polygermene

A new polymer with an alternating germanium-carbon backbone has been synthesized from 1,1-dimesitylneopentylgermene via addition polymerization using an anionic initiator

Methylmagesium Alkoxide Clusters with Mg4O4 Cubane and Mg7O8 Biscubane Like Cores Organometallic Precursors for Low Temperature Formation of MgO Nanoparticles with Variable Surface Defects

Nanocrystalline MgO powders with variable surface defect concentrations are simply accessible by solid state thermolysis at relatively low temperatures utilizing the molecular single source precursors SSPs [MeMgOR] 4 R Pr i, Bu t, Cy Hex and the first bis cubanes Me6Mg7 OR 8 Et, Pr, Bu . The decomposition conditions including heating rates, tempering times, and atmospheres have been varied, and the structure and purity of the obtained samples were analyzed by means of different analytical techniques TGA, PXRD, TEM, EDX, elemental analysis and BET measurements . The crystal sizes vary from approximately 8 to 15 nm depending on the heating rates, tempering times and nature of the applied SSP. Photoluminescence spectroscopy PLS of the samples suggests the presence of defects, which Could be attributed to different surface oxide sites of the MgO particles depending on the thermolysis conditions, in particular the heating rate and tempering time. year 2010 volume 22 issue 4 pages 1376 1385 doi 10.1021 cm902153

Reply to Comment on Methylmagnesium Alkoxide Clusters with Mg4O4 Cubane and Mg7O8 Biscubane Like Cores Organometallic Precursors for Low Temperature Formation of MgO Nanoparticles with Variable Surface Defects

Reply to Comment on Methylmagnesium Alkoxide Clusters with Mg4O4 Cubane and Mg7O8 Biscubane Like Cores Organometallic Precursors for Low Temperature Formation of MgO Nanoparticles with Variable Surface Defects CHEMISTRY OF MATERIALS year 2010 volume 22 issue 15 page 4513 doi 10.1021 cm101691

Unprecedented Alkylzinc Magnesium Alkoxide Clusters as Suitable Organometallic Precursors for Magnesium Containing ZnO Nanoparticles

The synthesis and characterization of the first heterobimetallic methylzinc magnesium alkoxide clusters [Me6MgZn6 OR 8 ] [R Et 1a , nPr 1b , nBu 1c ] with a bis cubane shaped MgZn6O8 core is described. The thermal degradation of 1a c and mixtures of 1a and the homometallic MeZn alkoxide cubane [ MeZnOtBu 4 ] 2 in dry synthetic air led to wide band gap semiconducting MgxZn1 xO nanoparticles at temperatures below 500 degrees C. The final materials were characterized by different analytical techniques such as PXRD, REM, TEM, EDX, and IR spectroscopy. The morphology of the as prepared magnesium containing ZnO samples is influenced by the different organo groups alkoxo in the precursors. EDX mapping showed that magnesium is uniformly distributed in the ZnO matrix. The incorporation of magnesium led to a distortion of the ZnO lattice with increased a axis and decreased c axis parameters. Room temperature photoluminescence PL spectra reveal that the near band edge NBE emission of Mg2 doped ZnO is shifted to higher energies relative to that of pure ZnO. year 2011 volume 17 issue 14 pages 3904 3910 doi 10.1002 chem.20100274