Binuclear ruthenium complexes containing mPTA and alkyl-bis(8-thiotheophylline) derivatives (mPTA = N-methyl-1,3,5-triaza-7-phosphaadamantane)

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

“…All the recorded electrode potentials were in a short range similar to those found for ruthenium complexes containing Cp and PTA [23]. The three oxidation waves for the complexes only can be assigned to single-electron charge transfer of two independent Ru centers (Ru II Ru II /Ru III Ru II and Ru III Ru II /Ru III Ru III ) and therefore, support the proposed bimetallic character for the complexes [10,24,25]. It is interesting to stress that also for these complexes the oxidation potentials decrease linearly when the bispurine-alkyl-bridging group increases in length (Eox(1) = 706 mV (1); 546 mV (2); 469 mV (3); Eox(2) = 880 mV (1); 826 mV (2); 813 mV ( 3)).…”

“…Complexes [{RuCp(PPh3)(mPTA)}2-μ-(Y-kS,S′)] showed that the combination of bispurines with ruthenium with mPTA, soluble in water, and PPh3, soluble in organic solvents, are non-reactive against DNA. Their low solubility in the standard dmso/water mixture avoided the evaluation of their antiproliferative activity against living cells [10]. Nevertheless, these complexes showed that their oxidation potentials are related with the purine linking group size.…”

“…parent complexes [{RuCp(PPh3)(PTA)}2-μ-(PBTT-kS7,S′7)], [{RuCp(PTA)2}2μ-(PBTT-kS7,S′7)] [9] and [{RuCp(PPh3)(mPTA)}2-μ-(L-kS7,S′7)][10]. The calculated energy difference D(HOMO-LUMO) is in agreement with that tendency as it is 3532 eV for 1, 3345 eV for 2 and 3584 eV for 3.…”