Ruthenium complexes containing mPTA and thiopurines bis(8-thiotheophylline)-(CH2)n (n = 1 – 3; mPTA = N-methyl-1,3,5-triaza-7-phosphaadamantane)

Thiopurines bis(S-8-thiotheophylline)methane (MBTTH2), 1,2-bis(S-8-thiotheophylline)ethane (EBTTH2), and 1,3-bis(S-8-thiotheophylline)propane (PBTTH2) were reacted with [RuClCp(mPTA)2](CF3SO3)2 in water to afford the bis-ruthenium complexes [{RuCp(mPTA)2}2-μ-(L-κN7,N′7)](CF3SO3)4 (1: L = MBTT; 2: L = EBTT; 3: L = PBTT), which have been characterized by elemental analysis, IR, and multinuclear NMR (1H, 13C{1H}, 31P{1H} and 19F{1H}) spectroscopy). Diffusion experiments for 1 were carried out. Proposed structures for the three complexes were also supported by theoretical calculations. Cyclic voltammetry showed that these complexes are characterized by two one-electron irreversible oxidative response (RuII – RuII/RuIII – RuII; RuIII – RuII/RuIII – RuIII). Complexes showed poor antiproliferative activity against cisplatin-sensitive T2 human cell line and the cisplatin-resistant SKOV3 cell line.