Platinum complexes of oxopurines: cis-bis(theophyllinato-N7)bis(triphenylphosphine)platinum(II) and cis-chloro(theobrominato-N1)bis(triphenylphosphine)platinum(II) ethanol hemisolvate.

The syntheses and structures of two mixed-ligand complexes of platinum(II) with deprotonated oxopurine bases and triphenylphosphine are reported, namely the theophyllinate complex cis-bis(1,2,3,6-tetrahydro-1,3-dimethylpurine-2,6-dionato-kappaN(7))bis(triphenylphosphine-kappaP)platinum(II), [Pt(C(7)H(7)N(4)O(2))(2)(C(18)H(15)P)(2)], (I), and the theobrominate complex cis-chloro(1,2,3,6-tetrahydro-3,7-dimethylpurine-2,6-dionato-kappaN(1))bis(triphenylphosphine-kappaP)platinum(II) ethanol hemisolvate, [PtCl(C(7)H(7)N(4)O(2))(C(18)H(15)P)(2)].0.5C(2)H(5)OH, (II). In (I), the coordination geometry of Pt is square planar, formed by the two coordinating N atoms of the theophyllinate anions in a cis arrangement and two P atoms from the triphenylphosphine groups. In (II), there are two crystallographically independent molecules. They both exhibit a square-planar coordination geometry around Pt involving one Cl atom, the coordinating N atom of the theobrominate anion and two P atoms from the triphenylphosphine groups. The two triphenylphosphine groups are arranged in a cis configuration in both structures. The heterocyclic rings are rotated with respect to the coordination plane of the metal by 82.99(8) and 88.09(8) degree in complex (I), and by 85.91(16) and 88.14(18) degree in complex (II). Both structures are stabilized by intramolecular stacking interactions involving the purine rings and the phenyl rings of adjacent triphenylphosphine moieties.