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Complexes of Uracil (2,4-Dihydroxypyrimidine) Derivatives. Part II. Potentiometric and Luminescence Studies with Eu(III)

Kufelnicki A., Kupińska I., Lis S., Hnatejko Z.

Polish Journal of Chemistry

2003

Vol. 77 / nr 8

1019-1025

Luminescence spectroscopy studies were carried out on europium(III) complexation with HL = uracil, thymine (5-methyluracil), 6-chloromethyluracil, 5-hydroxymethyluracil and 6-methyluracil in acidic perchlorate solutions. In acidic medium the decrease of the hydration number with increasing the ligand excess indicates a consecutive complexation via metal - O4 coordination. The potentiometric method confirmed the possibility of coordination by N3 at higher pH for thymine, 6-chloromethyluracil and 6-methyluracil. The formation of hydroxo species has been ascertained for all the ligands.

Complexes of uracil (2,4-Dihydroxypyrimidine) Derivatives. Part I. Cu(II), Ca(II) and MG(II) Coordination with Uracil and Related Compounds in Aqueous Solution

Kufelnicki A., Kupińska I., Jezierska J., Ochocki J.

Polish Journal of Chemistry

2002

Vol. 76 / nr 11

1559-1570

Potentiometric pH studies were carried out on proton and metal (Cu(II), Ca(II) and Mg(II)) complexes of HL = uracil, thymine (5-methyluracil), 6-chloromethyluracil, 5-hydroxymethyluracil, 6-methyluracil and a diethyl 6-uracilmethylphosphonate derivative. For Cu(II) additional spectroscopic (absorption and EPR) measurements were carried out. The results have been compared with the literature data accessible only for uracil and thymine. A deprotonation of the ML complexes in a more basic solution was indicated, thus, extending the coordination mode proposed up to now for uracil and thymine. An electron withdrawing effect of substituents has been found for 6-chloromethyluracil and diethyl 6-uracilmethylphosphonate.