New palladium complexes with bis(8-thiotheophylline)alkane derivatives

Aiming at finding new models that allow us to obtain more information about the interaction between metals and purine-biomolecules, the new derivatives bis(S-8-thiotheophylline)methane (MBTTH2) (1), 1,2-bis(S-8-thiotheophylline)ethane (EBTTH2) (2), 1,3-bis(S-8-thiotheophylline)propane (PBTTH2) (3) and, 1,10-bis(S-8-thiotheophylline)decane (DBTTH2) (4) were synthesised. The evaluation of the coordinative properties of these new ligands against cis-[PdCl2(PPh3)2], leaded to the synthesis of the complexes trans-[PdCl(PPh3)2LH] (L=EBTT2− (5), PBTT2− (6)) and trans-[(PdCl(PPh3)2)2L] (L=MBTT2− (7), EBTT2− (8), PBTT2− (9), DBTT2− (10)). All of the ligands and complexes were characterised by elemental analysis, IR and multinuclear (1H, 13C{1H}, 31P{1H} NMR) spectroscopy. The crystal structure of the ligand 1 is also presented, confirming the proposed composition for the new purine derivatives.