Preparation And Structure Of Cis-[(Ethylenediamine)Bis(1,3,9-Trimethylxanthine)Platinum(Ii)] Nitrate Dihydrate And Cis-[(Ethylenediamine)Bis(1,3,9-Trimethylxanthine)Platinum(Ii)] Hexafluorophosphate - Effect Of Intramolecular And Intermolecular Interactions On Molecular-Conformation In The Solid-Stateam