Coordination modes of 9-methyladenine in cis-platinum(II) complexes with dimethyl(phenyl)phosphanes as ancillary ligands - Synthesis and characterization of cis-[PtL2(9-MeAd)(2)](NO3)(2),cis-[PtL2{9-MeAd(-H)}](3)(NO3)(3), and cis-[L2Pt{9-MeAd(-H)}PtL2](NO3)(3)