Stereospecific hydrogen-bonding in mononucleotide adducts

Ground-State Stability and Rotational Activation Parameters for Individual Rotamers of (R,S,S,R)-(N,N'-Dimethyl-2,3-diaminobutane)PtG2 Complexes (G = ...
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J. Am. Chem. SOC.1993,115, 8649-8659

8649

Stereospecific Hydrogen-Bonding in Mononucleotide Adducts of Platinum Anticancer Complexes in Aqueous Solution Susan J. Berners-Price,+Urban Frey,* John D. Ranford,$ and Peter J. Saderg** Contribution from the School of Science, Griffith University, Nathan, Queensland 41 1 1 , Australia, and the Department of Chemistry, Birkbeck College, University of London, Gordon House and Christopher Ingold Laboratories, 29 Gordon Square, London WCl H OPP, U.K. Received February 12, 1993

Abstract:The ammine and amine N-H ’H NMR resonances of Pt(I1) complexes containing 5’-phosphate derivatives of nucleobases undergo significant low-field shifts in aqueous solution consistent with stereospecificH-bonding between Pt-NH protons and cis nucleotide 5’-phosphate groups. The effects are strongest for N H protons held rigidly in a chelate ring (ethylenediamine, en, complexes), when the phosphate is fully deprotonated, and when rotation about Pt-N7 (head-to-tail isomerism) is slow, as in [Pt(en>(5’-AMP-N7)2l2+.The temperature dependences of Pt-NH 1H NMR resonances for these complexes are low (