Metal ions are critical for the proper folding of RNA, and the GAAA tetraloop-receptor is necessary for the optimal folding and function of many RNAs. We have used NMR to investigate the role of metal ions in the structure of the tetraloop-receptor in solution. The NMR data indicate native tertiary structure is formed under a wide range of ionic conditions. The lack of conformational adaptation...

We report the electrochemical detection of femtomolar amounts of cobalt, iridium, nickel, and iron ions in solution by electrocatalyst formation and amplification. The metal oxides of these ions can be formed electrochemically and can catalyze the oxidation of water. Alternatively, the reduction of metal ions to metals, such as the reduction of IrCl6(3-) to iridium, is capable of electrocatalyt...

Controlling the bio-inspired redox conversion of Co(II)–disulfide compounds to their related Co(III)–thiolate complexes is a perplexing task as factors triggering this reaction are not fully understood. Three disulfide ligands 2,2?–disulfanediylbis(N,N-bis((3,5–dimethyl-1H–pyrazol–1–yl)methyl)ethan-1-amine) (LmpzSSLmpz), 3,3?-disulfanedylbis(N,N-bis(pyridin-2-ylmethyl)propan-1-amine) (LpSSLp), ...

The functionality or oxidation state of cobalt within a silica matrix can be tailored through the use of cationic surfactants and their halide counter ions during the sol-gel synthesis. Simply by adding surfactant we could significantly increase the amount of cobalt existing as Co3O4 within the silica from 44% to 77%, without varying the cobalt precursor concentration. However, once the surfact...

With a series of local-density approximation plus Hubbard U calculations, we have demonstrated that for lanthanum cobaltite LaCoO3 , the electric field gradient at the cobalt nucleus can be used as a fingerprint to identify the spin state of the cobalt ion. Therefore, in principle, the spin state of the cobalt ion can be unambiguously determined from nuclear magnetic resonance spectra. Our calc...

In earlier inhalation exposures of rabbits, nickel increased the production of surfactant by type II cells, with secondary effects on morphology and function of alveolar macrophages. Cobalt induced mainly a nodular growth pattern of the type II cells. Trivalent chromium seemed to impair the capacity of macrophages to catabolize surfactant but did not affect the type II cells. We exposed rabbits...

Abstract This work reports a simple and sensitive on-line solid-phase extraction system for the pre-concentration determination of trace amount Co(II (ions by flame atomic absorption spectrometry (FAAS). method is based on retention cobalt ions with polyvinyl chloride modified 3-(2-thiazolylazo)-2,6-diaminopyridine in mini-column system. The retained Co(II) were eluted 1.0 mol L −1 HCl, direct ...

Keep in mind the importance of cadmium, cobalt and nickel ions as environmentally and economically strategic heavy metals, the application of two acidic extractants, named bis(2-diethylhexyl)phosphoric acid (DEHPA) and 2-thenoyltrifluoroacetone (HTTA), was assessed for the extraction-recovery of these ions from leached solution of spent rechargeable Ni-Cd batteries. The conditions for leach...

metal complexes, but is useful in the case of metal complexes with low extractability. This process has thus been applied to the separation of metals, which is difficult by conventional batch extraction.1 Extraction reagents (HR) are usually consumed in amounts several hundred times those of metals (M). Complexes to be extractable into an organic solvent {MRn·(HR)m} are not always obtained usin...

Cobalt is widespread in the natural environment and can be formed as an effect of anthropogenic activity. This element is used in numerous industrial applications and nuclear power plants. Cobalt is an essential trace element for the human body and can occur in organic and inorganic forms. The organic form is a necessary component of vitamin B12 and plays a very important role in forming amino ...