Astatine (Z = 85) is the heaviest member of the elements of group 17 of the Periodic System (halogens). About 20 isotopes are known, and some of them have been identified as short-lived products in the natural radioactive series. The longest-lived isotope is 210At with a half-life of only 8.3 hours. Consequently, macroscopic quantities of this element cannot be accumulated. Our knowledge on its...

Perovskite materials host an incredible variety of functionalities. Although the lightest element, hydrogen, is rarely encountered in oxide perovskite lattices, it was recently observed as the hydride anion H(-), substituting for the oxide anion in BaTiO3. Here we present a series of 30 new complex hydride perovskite-type materials, based on the non-spherical tetrahydroborate anion BH4(-) and n...

We describe the functionalization of α-amino C-H bonds with aryl halides using a combination of nickel and photoredox catalysis. This direct C-H, C-X coupling uses inexpensive and readily available starting materials to generate benzylic amines, an important class of bioactive molecules. Mechanistically, this method features the direct arylation of α-amino radicals mediated by a nickel catalyst...

The chloroperoxidase (EC 1.11.1.-) from the fungus Curvularia inaequalis belongs to a class of vanadium enzymes that oxidize halides in the presence of hydrogen peroxide to the corresponding hypohalous acids. The 2.1 A crystal structure (R = 20%) of an azide chloroperoxidase complex reveals the geometry of the catalytic vanadium center. Azide coordinates directly to the metal center, resulting ...

The crystal packing in the structures of various solvent-free (mono)haloanilinium halides involves with one exception the formation of approximately planar hydrophilic regions that contain classical hydrogen bonds N-HþþþX (X = halogen). Common to the substructures of all layers are rings of general graph set Rn2n(4n), involving equal numbers of chloride acceptors and NH2 moieties (two hydrogen ...

Diphenyl(2-hydroxy-phenyl)phosphine was introduced as a ligand for gold(I) halides and pentafluorophenyl gold(I) in order to probe the interplay of intraand intermolecular interactions based on aurophilic (Au Au) and hydrogen bonding. 1:1 complexes of the type Ph2(2-HOC6H4)P-Au-X with X = Cl, Br, C6F5 have been prepared and characterized by analytical and spectroscopic data. The crystal structu...

To date more than 3650 organohalogen compounds are known to be naturally produced by biogeochemical processes [1]. The current understanding of the abiotic formation of organohalogens during early diagenetic processes in soils and sediments are reviewed. Next to volatile alkyl halides and polar organohalogens such as haloacetates there is evidence that even semivolatile organohalogens (e.g. pol...

Accurate calculations are made for the hydration energies of the alkali halides, using the most recent data. These results, and the average of theoretical calculations made by others for the individual ions, are used to determine the most probable hydration energy of the individual ions. These in turn are the basis for calculating the absolute enthalpy of formation of aqueous H: 98.6 kcal/g-equ...

The hydration structure in aqueous solutions of three tetraalkylammonium halides (TAAX), tetramethylammonium chloride (TMACl), tetrapropylammonium bromide (TPABr), and tetrabutylammonium bromide (TBABr) at concentrations of 2.2, 1.4, and 1.0 m, respectively, is studied via molecular dynamics (MD) simulation at ambient conditions. The results are compared directly with neutron diffraction with i...