Preparation and Structural Characterization of Methylmercury(II) Complexes of 5-Aza- and 6-Azauracil Derivatives

Open Access
Publisher Website
Google Scholar
Abstract
1:1 Methylmercury(II) complexes of the anti-tumour agent 6-azauracil (6AUH2) and its deriva­tives 6-azathymine (6ATH2). 1-methyl-6-azauracil (6AMUH) and 1-methyl-6-azathymine (6AMTH) have been isolated from aqueous solutions of CH3HgOH and the respective base. N3-Coordination was established by X-ray structural analysis for both [(CH3Hg)6 AUH] (1) (pH 6-8) and [(CH3Hg)6 AMT] (5) (pH 4-12); in addition 1H NMR data are in accordance with an identical binding site in the complexes [(CH3Hg)6AMU] (3) and [(CH3Hg)6 ATH] (4). Using an excess of CH3HgOH. 2:1 complexes with N1, N3-coordination may be prepared for both 6 AUH: and 5 AUH2 in a wide pH range (4-12 and 6-12 respectively). At pH values of 3-4 a 3:1 complex [(CH3Hg)35 AU]NO3 (7), with N1, N3, N5-coordination may be isolated: the binding sites were confirmed by X-ray structural analysis. In no case could an ionic complex with N6- coordination be isolated for a 6-azapyrimidine derivative. The binding preferences of the bases are discussed in the light of MNDO calculations.

This publication has 0 references indexed in Scilit: