The protonation equilibria of four substituted N-methylbenzenesulfonamides, X-MBS: X = 4-MeO (3a), 4-Me (3b), 4-Cl (3c) and 4-NO(2) (3d), in aqueous sulfuric acid were studied at 25 °C by UV-vis spectroscopy. As expected, the values for the acidity constants are highly dependent on the electron-donor character of the substituent (the pK(BH+) values are -3.5 ± 0.2, -4.2 ± 0.2, -5.2 ± 0.3 and -6....

The Raman intensity versus electrode voltage behavior of a series of substituted pyridines and saturated nitrogen heterocycUc compounds was studied at two laser excitation energies. The voltage (resonance) maximum shifts to more positive potential with increasing excitation energy for the substituted pyridines (case I) and to more negative potential with increasing excitation energy for the sat...

Over 60 lignin-related model compounds were phosphitylated with 2chloro-4,4,5,5-tetramethyldioxaphospholane, a sterically hindered analogue of 2-chloro-1,3,2-dioxaphospholane used in earlier work, and their 31P chemical shifts were recorded. Excellent resolution between the chemical shifts of phosphitylated carboxylic acids, phenols and aliphatic alcohols was obtained. The correlations of the p...

The kinetics of reduction of cytochrome c by catechol(s), quinol(s) and related compounds were investigated by stopped-flow spectrophotometry. Studies on the influence of pH on the rates indicate that only deprotonated forms of these compounds act as reducing agents, with the dianionic forms being the most effective. The pH-independent second-order rate constants are reported. Hammett treatment...

In recent years many efforts have been made aiming to define the conditions of the reaction of substitution which lead to inversion of configuration (Walden inversion). The investigations in this direction of Polanyi et al.,’ of Olson,2 of Hughes, Ingold, et aL3 are most outstanding. Polanyi et al. and Olson came to the conclusion that all reactions of substitution by a negative group or ion ar...

A series of beta-(N-tosyl)amino diazo carbonyl compounds have been prepared by nucleophilic condensation of N-tosylimines with acyldiazomethanes. The diazo decomposition of these diazo carbonyl compounds under various catalytic conditions, including Rh(II) carboxylates, Cu(I) and Cu(II) complexes, PhCO(2)Ag/Et(3)N, TsOH, and SnCl(2).2H(2)O, has been investigated. It was found that, in most case...

In the present paper [VO(acac)2] reacts with an equimolar amount of tridentate dibasic ONO donor hydrazone ligand derived from the condensation of benzoyl hydrazine with either 2hydroxyacetophenone (H2L 1) or its para-substituted derivatives (H2L 2) (general abbreviation H2L), in the presence of excess amount of salicylaldehyde (Hsal) in methanol under aerobic conditions producing the mixed-lig...

In this study, the Ni(II) Schiff base/SBA-15 catalyst was successfully synthesized and characterized by employing FT-IR, XRD, TGA, EDX, ICP-OES, TEM, SEM analysis. addition, BJH BET techniques were used to determine specific surface area, pore size, volume of catalyst, which 538 m2 g−1, 6 nm, 1.01 cm3 correspondingly. Under favorable conditions, we have designed a one-pot multicomponent reactio...