Synthesis and characterization of pillared buserite

Abstract

I 0.0 -0.4 -0.8 E(V) vs AglAgCl F g u e 5. Cyclic voltammogram of 1.0 mmol dm-, [IC0(aet),],Zn,0]~+ (cation of 2) in 0.1 mol aqueous solution of NaNO,. The scan rate is 50 mV s-I.region (32-48) X lo3 cm-' (Figure 3). This CD spectral deviation suggests that the asymmetric bridging sulfur atoms of the central cos6 chromophore in AA-[Co(Co(aet),},13+ contribute conspicuously to the CD spectrum in the region (16-30) X lo3 cm-l.Electrochemical experiments were performed in a 0.1 mol dm-3NaNO, aqueous solution at a glassy carbon electrode. As shown in Figure 5, the cyclic voltammogram of [{C~(aet),),Zn,O]~+ (2) initiated at 0.0 V with a negative potential scan yields four consecutive reduction waves (E, = -0.44, -0.56, -0.69, -0.87 V) and coupled four oxidation waves (E, = -0.36, -0.48, -0.61, and -0.79 V). No other redox couple is observed in the potential region of +0.8 to -1.2 V (vs Ag/AgCl). The peak current is approximately proportional to the square root of the scan rate. At a scan rate of 50 mV s-I, the ratio of cathodic to anodic peak current is approximately unity and the observed peak separation (E, -E, )In order to estimate the structure of 1, its cyclic voltammetric measurement was performed under the same conditions as used for 2. The cyclic voltammogram of 1 gave broad and nonreversible four consecutive reduction waves at E, = -0.45, -0.57, -0.71, and -0.89 V. This electrochemical behavior analogies with that of 2, although the relative instability of 1 in water restricts the electrochemical characterization. In addition, the absorption spectrum of 1 is quite similar to that of 2 over the whole region, as shown in Figure 4. These facts suggest that 1 has a cage-type S-bridged structure similar to that of 2. The plasma emission spectral analysis indicates that 1 contains Co and Zn in a ratio of 4:3. Accordingly, it is likely that 1 is the cagatype S-bridged complex with a "defective" [Zn3BrI5+ core, [ { C ~( a e t ) ~} ~Z n ~B r ] ~+ , considering that the formation of 1 was achieved by the addition of a large amount of NaBr to the reaction solution of fa@')- [Co(aet),] and ZnZ+.Registry No. 1, 139100-76-8; %Br6 (A-isomer), 139100-77-9; 2. Br6.9.5H20 (A-isomer), 139236-12-7; 26+ (A-isomer), 139236-13-8; fac-(S)-[Co(aet),], 18703-22-5; A A -[ C ~( C O ( ~~~) ~) ~] (NO,)3, 129387-95-7;Table SI, listing anisotropic thermal parameters (1 page); Table SII, listing observed and calculated structure factors (8 pages). Ordering information is given on any current masthead page. ALLL-~uc(S)-K~ [ CO( L-cYs-N,~), 1, 97 8 60-43-0.

Hydration-induced spin-glass state in a frustrated Na-Mn-O triangular lattice

“…Due to their modular porosities, high thermal surface area and stabilities, these compounds find numerous technological applications such as their use in ion sieves, molecular sieves, catalysts [4,5] and electrodes in batteries. One of the most prominent characteristics of manganese oxides is that their structure can be used as a host material for intercalation and de-intercalation reactions.…”

Characterization of Mn oxides in cemented streambed crusts from Pinal Creek, Arizona, U.S.A., and in hot-spring deposits from Yuno-Taki Falls, Hokkaido, Japan

“…There is an increasing interest in Mn-oxide minerals, as they are the major constituents of marine Mn deposits (Usui 1979;Mellin and Lei 1993;Glasby et al 1996;Usui and Someya 1997;Usui and Glasby 1998) and potentially can be used as molecular sieves (Shen et al , 1994(Shen et al , 1996Wasserman et al 1995;Tian et al 1997) and as catalysts (Wong and Cheng 1992;Cao and Suib 1994;Ching and Suib 1997;Ramamouthy et al 1999). In addition, Mn-oxide minerals are commonly ac-* E-mail: bilinski@rudjer.irb.hr…”

Poly(aniline)/MnO<SUB>2</SUB> Supported Palladium—A Facile Nanocatalyst for the Electrooxidation of Methanol

“…Manganese oxide (MnO 2 nanotube was prepared by a hydrothermal method. 17 Pani/MnO 2 nanocomposite was prepared as follows: about 1 ml of freshly distilled aniline was dissolved in 10 ml water and a few drops of dil.HCl. About 50 mg of prepared MnO 2 was dispersed in the aniline solution and subjected to ultrasonication.…”