Reactions of monosubstituted dithizonates MDz(2) [M = Cu(II), Co(II), Ni(II
), Cd(II), Hg(II), and Zn(II)I with N-methyltetraphenylporphin H(N-CH3)TPP
in dimethyl sulfoxide are studied. It is found that Cu(II), Ni(II), and Hg(
II) dithizonates do not enter this reaction. The rate of complexation betwe
en H(N-CH3)TPP and Co(II), Cd(II), and Zn(II) dithizonates increases in the
order of Co < Zn < Cd. The reaction mechanism and reasons for different ca
pability of dithizonates for coordinating with NH-active porphyrins are sug
gested.