Synthesis, and characterization of ruthenium(II) polypyridyl complexes containing α-amino acids and its DNA binding behavior

Reactivity of the ruthenium complexes [Ru(κ3-tptz)(PPh3)Cl2] (1) and [Ru(κ3-tpy)(PPh3)Cl2] (2) [tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine; tpy = 2,2′:6′,2″-terpyridine] with several α-amino acids [glycine (gly); leucine (leu); isoleucine (isoleu); valine (val); tyrosine (tyr); proline (pro) and phenylalanine (phe)] have been investigated. Cationic complexes with the general formulations [Ru(κ3-L)(κ2-L″)(PPh3)]+ (L = tptz or tpy; L″ = gly, leu, isoleu, val, tyr, pro, and phe] have been isolated as tetrafluoroborate salts. The resulting complexes have been thoroughly characterized by analytical, spectral and electrochemical studies. Molecular structures of the representative complexes [Ru(κ3-tptz)(val)(PPh3)]BF4 (6), [Ru(κ3-tpy)(leu)(PPh3)]BF4 (10) and [Ru(κ3-tpy)(tyr)(PPh3)]BF4 (13) have been determined crystallographically. The complexes [Ru(κ3-tptz)(leu)(PPh3)]BF4 (4), [Ru(κ3-tptz)(val)(PPh3)]BF4 (6), [Ru(κ3-tpy)(leu)(PPh3)]BF4 (10) [Ru(κ3-tpy)(tyr)(PPh3)] BF4·3H2O (13) exhibited DNA binding behavior and acted as mild Topo II inhibitors (10–40%). The complexes also inhibited heme polymerase activity of the malarial parasite Plasmodium yoelii lysate.