Oxygen, sulfur, selenium, tellurium and polonium

Syntheses, Structures, and Electronic Properties of a New Series of Tellurides of the Type [Sequestered Cation]2(Tex) (x = 1–4)

“…The latter included solvated telluride salts. Since then, a large progress has been made in the area of non‐classical tellurides, including one, two and three‐dimensional telluride architectures,2f,4a,4b rings and cage formations,4c heterometallic, macrocyclic and carbene analogeous tellurium compounds4d,4e,4f,4g as well as the syntheses of a large variety of telluronium, tellurolate,4h,4i and polycationic tellurium salts 4j,4k,4l,4m. Nevertheless, the total number of so‐called “organic cation” tellurides, which contain either alkali metal or alkaline‐earth metal cations in solvent, crown ether or cryptand complexes, or ammonium or phosphonium ions, is still small.…”

“Covalent Hydration” Reactions in Model Monomeric Ru 2,2′-Bipyridine Complexes: Thermodynamic Favorability as a Function of Metal Oxidation and Overall Spin States

“…Spectroscopic and EPR evidence suggesting intermediary OH addition to the ring were obtained. More recently, this model has been adapted to rationalize an unusual reaction pathway for water oxidation catalyzed by dimeric μ-oxo-bridged ruthenium ions ([Ru III (L) 2 (OH 2 )] 2 O 4+ , L = 2,2′-bipyridine or a ring-substituted congener) whichO-isotope-labeling studies have identified as involving O 2 formation from two solvent molecules, as opposed to the coordinated aqua ligands. , The active form of this catalyst is a 4e – -oxidized species containing a diruthenyl (Ru V (O)–O–Ru V (O)) core , that we proposed initiates water oxidation by H-atom abstraction; the nascent hydroxyl radical then undergoes concerted addition to either the adjacent RuO group to form a hydroperoxy/hydroxyl intermediate ([L 2 Ru IV (OOH)–O–Ru IV (OH)L 2 ] n + ) or the bipyridine ligand to form a ligand radical intermediate (for example, [L 2 Ru IV (OH)–O–Ru V (OH)L(LOH • )] n + ), which then decomposes to give an isotopically distinct O 2 molecule. Provisional support for this model includes detection of anomalous optical and EPR signals during catalytic turnover that appear consistent with OH addition to the ring as well as demonstration that radiolytically generated hydroxyl radical adds to the bipyridine ring .…”

“…These model complexes are structurally similar to [(tpy)(bpm)RuO] 2+/3+ and [(tpy)(bpz)RuO] 2+/3+ (bpm = 2,2′-bipyrimidine; bpz = 2,2′-bipyrazine) mononuclear catalysts, , although we recognize that the presence of the hard NH 3 ligands in the model may restrict electron delocalization over the nuclear framework of the complex. A common feature of homogeneous water oxidation reactions catalyzed by polyimine-containing complexes, particularly when excess oxidants are present, is competitive oxidative degradation that can inactivate the catalyst after only a few reaction cycles . These reactions can reasonably be expected to involve hydrolytic attack of water on reaction intermediates .…”