Speciation 98: Abstracts

New phosphinic dipeptides of the general formula H₂NCH₂CONHCH₂P(R)(O)(OH) where R = H, Me, Ph and t-Bu has been synthesised by active ester method (Z-Gly-Succ) from the free aminophosphinic acids based on literature. The crystal structure determination of the dipeptide derived from aminomethyl(phenyl)phosphinic acid confirmed a zwitterionic structure expected in the solid state. Bond distances and angels in peptide moiety are virtually the same as in common dipeptides and therefore, are not influenced by the phosphinic group (Figure 1).

Figure 1: Peptide part of the structure of Gly-AMP^Ph.H₂O

Protonation constants were determinated potentiometrically and protonation scheme was confirmed by ¹H and ³¹P NMR titrations. Basicity of amino group is almost the same like in the carboxylic and phosphonic analogues¹. On the other hand, acidity of phosphinic moiety is lowered in comparison to the free aminophosphinic acid². Complexing ability towards metals of the biological interest (Cu(II), Co(II), Ni(II) and Zn(II)) were investigated. The results found for phosphinic dipeptides are discussed and compared with the analogous common dipeptides and dipeptides with terminal phosphonic group.

References

1. P.Hermann, I.Lukes: J. Chem. Soc., Dalton Trans., 1995, 2605-10; P.Hermann, I.Lukes, P.Vojtísek, I Císaøová: J. Chem. Soc., Dalton. Trans., 1995, 2611-8; L.Bláha, I.Lukes, J.Rohovec, P.Hermann: J.Chem.Soc., Dalton Trans., 1997, 2621-8; I.Lukes, L.Bláha, F.Kesner, J.Rohovec, P.Hermann: J.Chem. Soc., Dalton Trans., 1997, 2629-37
2. T.Kiss, M.Jezowska-Bajczuk, H.Kozlowski, P.Kafarski, K.Antczak: J.Chem.Soc., Dalton Trans., 1991, 2275-81; J.Rohovec, I.Lukes, P.Vojtísek, I.Císaøová, P.Hermann: J. Chem. Soc., Dalton Trans., 1996, 2685-91

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