Extreme (109) acidification of adenine-NH2 in an open platinated nucleobase quartet. A pH switch with potential as a biological acid/base catalystElectronic supplementary information (ESI) available: table of the determined values of the different evaluated protons and Figures of the fits under discussion. See http://www.rsc.org/suppdata/cc/b1/b105395g/

Abstract

The combination of electronic effects (Pt^II binding to N⁷ and N¹) and a favourable conformation permitting efficient stabilization of the anion brings about a 10⁹ fold increase in the exocyclic amino group acidity of 9-ethyladenine.