Tr. Varga et al., Complexation properties of some aminocarboxylate ligands containing in-chain phosphinate group, ACH-MODEL C, 136(4), 1999, pp. 431-439
The complexation properties of the ligands bis(sarcosinato-N-methyl)-(L-1),
bis(L-prolinato-N-methyl)- (L-2), bis(iminodiacetato-N-methyl) (L-3) and b
is(morpholinato-N-methyl)phosphinic acid (L-4) were studied by pH-potentiom
etric titration, by spectrophotometry and by H-1-NMR spectroscopy. The basi
city of L-1, L-2, L-3 and L-4 is lower than that of the two composing ligan
ds. However, the stability constants of complexes (logK(ML)) formed with Mg
2+, Ca2+, Cu2+, Zn2+ and some lanthanide(III) ions are in general higher (t
he exceptions are the complexes CuL1 and CuL2) than the log beta(2) values
of the sarcosinate, L-prolinate and iminodiacetate complexes, indicating th
e participation of the phosphinate group in complexation. ML3 are particula
rly high and the AB multiplet pattern of the H-1-NMR spectrum of ZnL3 shows
the rigid structure of the complex.