Reactions of *NO2 with chromium(III) complexes with histamine and pyridoxamine ligands studied by the stopped-flow technique.
This study demonstrated the direct formation of the nitrogen dioxide (*NO2) radical during the decomposition of 3-morpholinosydnonimine (SIN-1) in biological buffer 4-morpholinoethanosulfone acid solution. Consequently, at approximately pH 4, SIN-1 can be used successfully as a source of *NO2. This conclusion is drawn from a comparison of the reactions of cis-[Cr(C2O4)(L- L)(OH2)2]+, where L-L denotes pyridoxamine (Hpm) or histamine (hm), with the gaseous *NO2 radical obtained by two methods: from SIN-1 and from a simple redox reaction. These reactions were investigated using the stopped-flow technique. The measurements were carried out at temperatures ranging from 5 to 25 degrees C over a pH range from 6.52 to 9.11 for cis-[Cr(C2O4)(Hpm) (OH2)2]+ and from 6.03 to 8.15 for cis-[Cr(C2O4)(hm)(OH2)2] +. We also determined the thermodynamic activation parameter (E(a)) and the uptake mechanism for each of the coordination compounds studied.
Jacewicz
Dagmara
D
Department of General Chemistry, University of Gdańsk, Sobieskiego 18/19, 80-952 Gdańsk, Poland.
Lapińska
Agnieszka
A
Dabrowska
Aleksandra
A
Figarski
Adam
A
Woźniak
Michał
M
Chmurzyński
Lech
L
D002857:Chromium / Q000737:chemistry*; D017608:Chromium Compounds / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry*; D006632:Histamine / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008981:Molsidomine / Q000031:analogs & derivatives / Q000737:chemistry; D009585:Nitrogen Dioxide / Q000737:chemistry*; D011733:Pyridoxamine / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods*; D013696:Temperature; D013816:Thermodynamics
D017608:Chromium Compounds; D005609:Free Radicals; D002857:Chromium; C002385:linsidomine; D011733:Pyridoxamine; D006632:Histamine; D008981:Molsidomine; D009585:Nitrogen Dioxide