caa a22 4500 467919933 CHVBK 20180406152914.0 cr unu---uuuuu 170328e20060401xx s 000 0 eng 10.1007/s00706-005-0432-6 doi (NATIONALLICENCE)springer-10.1007/s00706-005-0432-6 Salt Effects on Reactivity of Some Fe(II)-Azo Complexes Catalyzing Disproportionation of Hydrogen Peroxide [Elektronische Daten] [Ali M. Shaker, Aida M. Awad, Mohamed S. S. Adam] Summary.: Salt effects on kinetics of oxidation and decomposition of novel low-spin Fe(II) complexes of azo amino acids with hydrogen peroxide have been investigated in aqueous medium. The ligands are derived from amino acids (DL-phenylalanine, DL-tryptophane, histidine, and alanine) and p-nitroso aromatic substituted amines (N,N-dimethyl-4-nitrosoaniline and N,N-diethyl-4-nitrosoaniline). Hydrophobic salts of alkali metal and tetraalkylammonium halides, e.g., KBr, tetrabutylammonium bromide (TBAB), tetraethylammonium bromide (TEAB), and tetramethylammonium bromide (TMAB) have been used. Dilute salt solutions exhibit little effects on the reactivities of oxidation and decomposition of the title compounds. This behaviour would be ascribed to a decrease in the activity coefficients of the reacting species in these solutions. Moreover, these effects support the reported pathway in these reactions occurring via the association of dicationic complexes and undissociated H2O2. On the other hand, higher salt concentration shows considerable effects on the reactivities. This behaviour is explained in terms of hydrophilicity of the complexes, ion pair formation, salting out, and substituent effects. Hyrophilic nature of the recent complexes enhances reactivity with increasing [KBr] due to salting out effects in the aqueous medium. Increasing [TBAB] retards reactivity via ion pair formation with the reactants. In the presence of R4N+ ions, the reactivity increases with changing R in the following order; R = C4H9 < C2H5 < CH3. The bulky R groups in the added tetraalkylammonium salts, exert medium steric hindrance against the approach of reactants. Springer-Verlag/Wien, 2006 Keywords. Salt effects nationallicence Iron(II) nationallicence Azo amino acids nationallicence Hydrogen peroxide nationallicence Shaker Ali M. Chemistry Department, Faculty of Science, Sohag South Valley University, 82524, Sohag, Egypt aut Awad Aida M. Chemistry Department, Faculty of Science, Sohag South Valley University, 82524, Sohag, Egypt aut Adam Mohamed S. S. Chemistry Department, Faculty of Science, Sohag South Valley University, 82524, Sohag, Egypt aut Monatshefte für Chemie / Chemical Monthly Springer-Verlag 137/4(2006-04-01), 421-431 0026-9247 137:4<421 2006 137 706 https://doi.org/10.1007/s00706-005-0432-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00706-005-0432-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Shaker Ali M. Chemistry Department, Faculty of Science, Sohag South Valley University, 82524, Sohag, Egypt aut NATIONALLICENCE 700 1- Awad Aida M. Chemistry Department, Faculty of Science, Sohag South Valley University, 82524, Sohag, Egypt aut NATIONALLICENCE 700 1- Adam Mohamed S. S. Chemistry Department, Faculty of Science, Sohag South Valley University, 82524, Sohag, Egypt aut NATIONALLICENCE 773 0- Monatshefte für Chemie / Chemical Monthly Springer-Verlag 137/4(2006-04-01), 421-431 0026-9247 137:4<421 2006 137 706 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer