Bis(Uracil-)-Complexes of Cisplatin: Preparation, Protonation and Metal Binding

(1,3-Dimethyluracil-5-yl)mercury(II): Preparative, Structural, and NMR Spectroscopic Studies of an Analog of CH3HgII

“…However, unlike in complexes with N(3)-bound Pt II , where this increase in basicity is clearly evident from pH * -dependent 1 H NMR and UV spectroscopy as well as potentiometric titration, the effect of C(5) bound to Hg II appears to be considerably smaller. It almost certainly does not exceed 2 log units considering the p K a of the protonated free ligand 1,3-DimeUH + (−3.25 ) and the fact that pH * -dependent 1 H NMR spectra do not reveal any protonation at least down to pH * = 0.…”

From Simpletrans-[a2Pt(2-hydroxypyrimidine)2]2+(a = NH3, CH3NH2) Complexes to Structures of Higher Complexity. Molecular Recognition of 2-Aminopyrimidine by Hydrogen Bond Formation and Reactivity toward Additional Metal Ions

“…Thus, there is no sign from 1 H NMR spectroscopy for protonation of the Hpymo ligands, at O2, in compounds 1a − 1c down to pH* 0, and we have no evidence of heterometal ion binding to this site. In this aspect Hpymo differs from the related uracil and thymine heterocycles for which an increased basicity of the exocyclic oxygens is found after Pt binding, as expressed by ready protonation and metal binding 2HpymoampymMeNH 2 compoundsH3H4H5H6H4, H6H5NH 2 MeNH 2 1a (D 2 O, pH* 3) 8.34 6.85 9.04 ( J 4,5 = 6.2, J 4,6 = 2.5) ( J = 5.9) ( J 5,6 = 5.7, J 4,6 = 2.5, J Pt, H = 43.8) 1b ( D 2 O, pH* 3) 8.39 6.89 9.19 2.21 ( J 4,5 = 6.2, J 4,6 = 2.5) ( J = 5.9) ( J 5,6 = 5.7, J 4,6 = 2.5, J Pt, H = 46.5) ( J = 12.8, J Pt, H = 38.6) 1b (dmso- d 6 ) 13.4 8.38 6.69 8.90 2.06 5.00 ( J 4,5 = 5.9, J 4,6 = 2.6) ( J = 5.9) ( J 5,6 = 5.5, J 4,6 = 2.4) ( J = 5.9) ( J = 5.7) 2 ( D 2 O, pH* 3) 8.38 6.86 9.19 8.38 6.86 2.21 ( J = 2.0) ( J = 3.1) 2 ( dmso- d 6 ) 13.4 8.38 6.69 8.90 8.21 6.55 6.63 2.06 5.00 ( J 4,5 = 5.9.2, J 4,6 = 2.6) ( J = 5.9) ( J 5,6 = 5.5, J 4,6 = 2.4) ( J = 4.8) ( J = 4.8) ( J = 5.9) ( J = 5.7) a Asterisk at pH denotes uncorrected pH meter reading. …”

Biomolecule−Mercury Interactions: Modalities of DNA Base−Mercury Binding Mechanisms. Remediation Strategies

“…The second aspect of our work concerns isotopic hydrogen exchange in heterocycles such as imidazole, histidine, and thiazole complexed to metal ions, deriving from the fact that isotopic hydrogen exchange of biomolecules in different environments has been a practical tool for probing biological function . These studies have been expanded to include metal ions other than CH 3 Hg II , to investigate substitution-inert complexes and to explore the chemistry of Pt II -based complexes as anticancer agents . These studies − have yielded significant information on the relative catalytic abilities of metal ions as surrogates for the proton,10a and emphasize the importance of the electronic structures of metal ions in determining reactivities in the ligand portion of the metal complexes.…”