A simple, selective and sensitive spectrophotometric method has been developed for the individual and simultaneous determination of Ti(IV) and Mo(VI) using salicylaldehyde p-hydroxybenzoylhydrazone (SAPHBH) in presence of Triton X100, without any prior separation. Beer’s law is obeyed between 0.15-2.0 and 0.20-2.51 μgmL concentration of Ti(IV) and Mo(VI) at 470 and 410 nm, respectively. The mol...

Reaction of the bulky bi-phenols 2,2′-RCH[4,6-(t-Bu)2C6H2OH]2 (R = Me L1MeH2, Ph L1PhH2) with the bis(imido) molybdenum(VI) tert-butoxides [Mo(NR1)(NR2)(Ot-Bu)2] (R1 = R2 = 2,6-C6H3-i-Pr2; R1 = t-Bu, R2 = C6F5) afforded, following the successive removal of tert-butanol, the complexes [Mo(NC6H3i-Pr2-2,6)2L1Me] (1), [Mo(NC6H3i-Pr2-2,6)2L1Ph] (2) and [Mo(Nt-Bu)(μ-NC6F5)(L1Me)]2 (3). Similar use of...

In this paper, we use first principles quantum mechanical methods (B3LYP flavor of Density Functional Theory) to examine the mechanism of selective oxidation and ammoxidation of propene by BiMoOx catalysts. To do this, we use finite clusters chosen to mimic likely sites on the heterogeneous surfaces of the catalysts. We conclude that activation of the propene requires a Bi(V) site, whereas all ...

In earlier publication1, the authors have reported data on the polarographic behaviour of molybdenum(VI) in three different organic acid media viz. mandelic acid, succinic acid and formic acid — sodium formate and concluded that in medium comprised of 0.1 M mandelic acid, 0.005% thymol and 0.1% camphor Mo(VI) produces a well defined irreversible diffusion controlled doublet wave, the total heig...

SBA-15 materials were functionalized through a post-synthetic methodology with molybdenum-Schiff bases to provide catalytic activity in epoxidation reactions. Thus, glycidoxypropyl functionalities were first attached to the surface of the mesostructured silica, followed by the reaction of the immobilized oxirane groups with 2-amino propyl pyridine. This reaction allowed the obtaining of (hydrox...

In this paper we use first principles quantum mechanical methods (B3LYP flavor of density functional theory) to examine the mechanism of selective oxidation and ammoxidation of propene by BiMoOx catalysts. To do this we use finite clusters chosen to mimic likely sites on the heterogeneous surfaces of the catalysts. We conclude that activation of the propene requires a Bi(V) site while all subse...

The changes in optical and EPR spectra observed during the anaerobic titration of xanthine oxidase with dithionite can be accounted for by simple oxidation-reduction equilibria involving Mo(VI) u MO(V) H Mo(IV); FAD cf FADH. ++ FADH2, and the l-electron reduction of each of the two ironsulfur centers. The equilibrium constants so obtained permit the calculation of the relative probabilities of ...

O açúcar mascavo é obtido a partir do caldo de cana-de-açúcar conservando suas propriedades quase inalteradas quando comparado à matéria-prima. cultivo da pode ser realizado por sistema agricultura convencional ou produção orgânica, o qual se destaca sua crescente demanda ligada ao apelo qualidade nutricional, segurança dos alimentos e questões ambientais. Este trabalho teve objetivo analisar a...

Abstract. To provide a tool for fast estimation of the Fe3+ content in Ca2(Al, Fe3+)3Si3O12(OH) epidote grains, including thin sections and crude-rock samples, we applied Raman spectroscopy to 33 areas from 15 natural samples with ranging 0.22 1.13 atoms per formula unit (apfu), chemistry which was independently determined by wavelength-dispersive electron microprobe analysis (WD-EPMA). The spe...