Synthesis and characterization of cis-[(PPh3)2Pt{9-MeAd(-H),N6N7}]X (X− = NO3, PF6): The first example of a platinum(II) complex containing the N6,N7-chelated 9-methyladenine anion

Reaction between the binuclear hydroxo complex cis-[(PPh3)2Pt(μ-OH)]2X2 (X− = NO3, 1a; PF 6 - , 1b) and the model DNA base 9-methyladenine (9-MeAd) leads to the formation of the mononuclear species cis-[(PPh3)2Pt{9-MeAd(-H),N6N7}]X (X− = NO3, 2a; PF6, 2b), in which the nucleobase chelates the Pt(II) ion with the N6 and N7 atoms. The coordination mode of the nucleobase has been determinated through a multinuclear (1H, 31P, 13C, 15N and 195Pt) NMR analysis and the nuclearity of the complex has been obtained by E.S.I. mass spectrometry. 2 represents the first example of an isolated platinum complex in which the NH2-deprotonated adenine exhibits this binding mode.