Stabile freie Radikale in Huminsäuren

Electron spin resonance of sedimentary humic acids in relation to their aromatic character

“…If free radicals in a sedimentary humic acid are in the form of simple semiquinone type, their g values must be similar to those of known semiquinones, such as 1, 4-benzosemiquinone (2.0047), 2-methyl 1,4-benzosemiquinone (2.0046), 1,4-naphthosemiquinone (2.0044) and ,9,10-anthrasemiquinone (2.0041) (BLOIS et al, 1961). The g values of a soil humic acid (2.005 5: KLEIST and MUCKE, 1966), peat and lignite (2.0040 2.0055: RETCOFSKY et al, 1968) are in good agreement with those of known semiquinone radicals. But g values of the sedimentary humic acids examined here are inconsistent with those of known semiquinone radicals.…”

“…Nature of stable free radicals in soil humic compounds has been studied by many investigators (REX, 1960;STEELINK and TOLLIN, 1962;TOLLIN et al, 1963;STEELINK, 1964STEELINK, , 1966KLEIST and MUCKE, 1966;ATHERTON et al, 1967;SCHNITZER and SKINNER, 1969;RIFFALDI and SCHNITZER, 1972). ATHERTON et al (1967) have studied free radicals in humic acids from lake sediments and found that ESR spectra are divided in two classes:…”

Huminstoffe als Radikale

“…Im Jahre 1961 gelang Steelink (3, 13) der Nachweis der Radikalnatur auch naturlicher Huminsauren. Und in jungster Zeit haben Kleist und Miicke (4) in einer ganzen Reihe synthetischer und naturlicher Huminsauren durch ESR-Messungen die Gehalte an Radikalen ermitteln konnen.…”