| Abstract (english) | EquHtbri1um studies were performed to invest:iga.te ithe com-
1plexa1tion of aqueous high-spin irnn(!I!) by three synthetic
monohydroxamic actds: acet-, glycin.ium, and be1ta1ne hydroxamic
acids. Under neutral and acidic conditions studied,
1acethydroxamic acid is neutral (AH), while glycinium CGH2+)
a.nd betaine CBH+) hydroxa.mic ac1ds have a positive charge
on ·the nitro:gen atom.
The equilibrium quotients ·for the formation of monoacethydroxamatoiron(
I!!) complex Qi', A-= [FeA2+J/( [Fe3+] [A- J ),
bisacethydroxamatoiroin(III) complex Q2', A-= [FeA2+J/( [Fe3+]
[A-]2), a.nd .tirisacethydroxamatoiiron(!I!) comp;lex Q3', A-=
= [FeA3]/([Fe3+J [A-]3) were found to be: lg Qi', A-= 10.38
(0.01), lg Q2', A-= 19.16 (0.14), and lg Q3', A- = 25.56 (0.70).
Ana.logous equiUbrimn quotients for glycinium-hydrnxamic
acid with protonated amino group (GH2+) and betaine-hydroxamic
ac·id CBH+) ligands are:
lg Qi', GH = [Fe(GH)3+J/([Fe3+J [GHJ) = 7.77 (0.08),
lg Q2', GH = [Fe(GH)i3+J/([Fe3+J [GHJ2) = 13.71 (0.08),
lg QJ', GH = [Fe.CGH)J3+]/([Fe3+J [GHJ3) = 17.63 (0.14),
lgQi',B = [FeB3+]/([Fe3+) [BJ)= 7.28 (0.02),
lgQ2',B = [FeB23+J/([Fe3+] [B]2) = 13.41 (0.05), and
lgQ3'.B = [FeB33+]/([Fe3+) [B]3) = 16.46 (0.24).
Determinations were made at 1.0 M ionic strength (NaCD
and at 25 °C by spectrophotometric methods.
The synthesis of a new compound beatine hydroxamic acid
chloride i1s desc·ri:bed.
INTRODUCTION |
