The complexation properties of the ligands bis(sarcosinato-N-methyl)- (L1), bis(L-prolinato-N-methyl)- (L2), bis(iminodiacetato-N-methyl) (L3) and bis(morpholinato-N-methyl)phosphinic acid (L4) were studied by pH-potentiometric titration, by spectrophotometry and by 1H-NMR spectroscopy. The basicity of L1, L2, L3 and L4 is lower than that of the two composing ligands. However, the stability constants of complexes (logKML) formed with Mg2+, Ca2+, Cu2+, Zn2+ and some lanthanide(III) ions are in general higher (the exceptions are the complexes CuL1 and CuL2) than the log β2 values of the sarcosinate, L-prolinate and iminodiacetate complexes, indicating the participation of the phosphinate group in complexation. ML3 are particularly high and the AB multiplet pattern of the 1H-NMR spectrum of ZnL3 shows the rigid structure of the complex.
|Number of pages||9|
|Journal||ACH - Models in Chemistry|
|Publication status||Published - Dec 1 1999|
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