Neutral stibinyl and bismuthinyl radicals are typically short-lived, reactive species. Here we show the synthesis and solid-state structures of two stable stibinyl [L(Cl)Ga]2Sb· 1 and bismuthinyl radicals [L(I)Ga]2Bi· 4, which are stabilized by electropositive metal centers. Their description as predominantly metal-centered radicals is consistent with the results of NMR, EPR, SQUID, and DFT studies. The Lewis-acidic character of the Ga ligands allow for significant electron delocalization of the Sb- and Bi- unpaired radical onto the ligand. Single-electron reduction of [L(Cl)Ga]2Sb· gave LGaSbGa(Cl)L 5, the first compound containing a Ga=Sb double bond. The π-bonding contribution is estimated to 9.56 kcal mol−1 by NMR spectroscopy. The bonding situation and electronic structure is analyzed by quantum mechanical computations, revealing significant π backdonation from the Sb to the Ga atom. The formation of 5 illustrates the high-synthetic potential of 1 for the formation of new compounds with unusual electronic structures.

No abstract

This Minireview aims to give an introduction to beryllium chemistry for all less-experienced scientists in this field of research. Up to date information on the toxicity of beryllium and its compounds are reviewed and several basic and necessary guidelines for a safe and proper handling in modern chemical research laboratories are presented. Interesting phenomenological observations are described that are related directly to the uniqueness of this element, which are also put into historical context. Herein we combine the contributions and experiences of many scientist that work passionately in this field. We want to encourage fellow scientists to reconcile the long-standing reservations about beryllium and its compounds and motivate intense research on this spurned element. Who on earth should be able to deal with beryllium and its compounds if not chemists?

Crystalline Co 3 O 4 nanoparticles with a uniform size of 9 nm as shown by Xray diffraction (XRD) and transmission electron microscopy (TEM) were synthesized by thermal decomposition of cobalt acetylacetonate in oleyl amine and applied in the oxidation of 2-propanol after calcination. The catalytic properties were derived under continuous flow conditions as function of temperature up to 573 K in a fixed-bed reactor at atmospheric pressure. Temperature-programmed oxidation, desorption (TPD), surface reaction (TPSR) and 2-propanol decomposition experiments were performed to study the interaction of 2-propanol and O 2 with the exposed spinel surfaces. Co 3 O 4 selectively catalyzes the oxidative dehydrogenation of 2-propanol yielding acetone and H 2 O and only to a minor extent the total oxidation to CO 2 and H 2 O at higher temperatures. The high catalytic activity of Co 3 O 4 reaching nearly full conversion with 100% selectivity to acetone at 440 K is attributed to the high amount of active Co 3+ species at the catalyst surface as well as surface-bound reactive oxygen species observed in the O 2 TPD, 2-propanol TPD, TPSR, and 2-propanol decomposition experiments. Density functional theory calculations with a Hubbard U term support the identification of fivefold coordinated octahedral surface as the active site, Co 3 + 5c and oxidative dehydrogenation involving adsorbed atomic oxygen was found to be the energetically most favored pathway. The consumption of surface oxygen and reduction of

Identifying the intrinsic electrocatalytic activity of nanomaterials is challenging, as their characterization usually requires additives and binders whose contributions are difficult to dissect. Herein, we use nano impact electrochemistry as an additive-free method to overcome this problem. Due to the efficient mass transport at individual catalyst nanoparticles, high current densities can be realized. High-resolution bright-field transmission electron microscopy and selected area diffraction studies of the catalyst particles before and after the experiments provide valuable insights in the transformation of the nanomaterials during harsh oxygen evolution reaction (OER) conditions. We demonstrate this for 4 nm sized CoFe 2 O 4 spinel nanoparticles. It is revealed that these particles retain their size and crystal structure even after OER at current densities as high as several kA•m −2 . The steady-state current scales with the particle size distribution and is limited by the diffusion of produced oxygen away from the particle. This versatilely applicable method provides new insights into intrinsic nanocatalyst activities, which is key to the efficient development of improved and precious metal-free catalysts for renewable energy technologies.

Highly active, structurally disordered CoFe2O4/CoO electrocatalysts are synthesized by pulsed laser fragmentation in liquid (PLFL) of a commercial CoFe2O4 powder dispersed in water. A partial transformation of the CoFe2O4 educt to CoO is observed and proposed to be a thermal decomposition process induced by the picosecond pulsed laser irradiation. The overpotential in the OER in aqueous alkaline media at 10 mA cm−2 is reduced by 23% compared to the educt down to 0.32 V with a Tafel slope of 71 mV dec−1. Importantly, the catalytic activity is systematically adjustable by the number of PLFL treatment cycles. The occurrence of thermal melting and decomposition during one PLFL cycle is verified by modelling the laser beam energy distribution within the irradiated colloid volume and comparing the by single particles absorbed part to threshold energies. Thermal decomposition leads to a massive reduction in particle size and crystal transformations towards crystalline CoO and amorphous CoFe2O4. Subsequently, thermal melting forms multi-phase spherical and network-like particles. Additionally, Fe-based layered double hydroxides at higher process cycle repetitions emerge as a byproduct. The results show that PLFL is a promising method that allows modification of the structural order in oxides and thus access to catalytically interesting materials.

Something to zinc about: A base‐stabilized [Zn2]2+ dication, obtained from the reaction of [Cp*2Zn2(dmap)2] (Cp*=C5Me5, dmap=4‐dimethylaminopyridine) with two equivalents of [H(OEt2)2][Al{OC(CF3)3}4], is structurally characterized for the first time (see structure; red Zn, blue N, gray C; ZnZn 2.419(1) Å).

No abstract