Metal−Purine Interactions: Homo- and Heterodinuclear Platinum(II) and/or Palladium(II) Complexes of 8-Thiotheophylline. Crystal Structures of [Pt(μ-TT)(dppm)]2·2DMSO and [(dppm)Pt(μ-TT)2Pd(dppm)]·7H2O | Publicación