Ruthenium–Thymine Acetate Binding Modes: Experimental and Theoretical Studies

Ruthenium complexes have proved to exhibit antineoplastic activity, related the interaction of metal ion with DNA. In this context, synthetic and theoretical studies on ruthenium binding modes thymine acetate (THAc) been focused shed light structure-activity relationship. This report deals reaction between dihydride mer-[Ru(H)2(CO)(PPh3)3], 1 acetic acid (THAcOH) selected as model for nucleobase derivatives. The in refluxing toluene THAcOH excess, by H2 release affords double coordinating species κ1-(O)THAc-, κ2-(O,O)THAc-[Ru(CO)(PPh3)2], 2. X-ray crystal structure confirms a simultaneous monohapto, dihapto- THAc coordination reciprocal facial disposition. Stepwise additions allowed intercept monohapto mer-κ1(O)THAc-Ru(CO)H(PPh3)3] 3 dihapto trans(P,P)-κ2(O,O)THAc-[Ru(CO)H(PPh3)2] 4 species. Nuclear magnetic resonance (NMR) studies, associated DFT (Density Function Theory)-calculations energies analogous reactions acid, supported proposed path. As evidenced supramolecular hydrogen-binding packing 1H NMR spectra, seems play pivotal role stabilizing minor [(N=C(OH)] lactim tautomers, which may promote mismatching DNA pairs clue its anticancer activity.