Interaction of carbonylchlorohydridotris (triphenylphosphine) ruthenium (II) with purine, adenine, cytosine and cytidine

Abstract

Many heavy metal ions are toxic in nature and certain complexes show antineoplastic activity. The interaction of the metal ions with DNA constituents might cause these. The biologically important nucleic acids constituents provide potential binding sites for metal ions.As a number of factors are responsible for the ability of the various donor atoms of nucleosides and nucleotides to act as sites of complexation, it is difficult to predict the binding sites for metal ions in a metal complex. The present paper deals with studies of carbonylchlorohydridotris (triphenylphosphine) ruthenium (II) complex with purine (PUR), adenine (ADN), cytosine (CTS) and cytidine (CTD). Investigations were undertaken to examine any change in the potential binding sites of the ligands which were reported for simple metal ions due to the presence of the triphenylphosphine ligands which could create steric restrants. Experimental Materials: The chemicals used were of AnalaR grade. PUR, ADN, CTS, CTD and [(C 6 H 5 ) 3 P] 3 Ru(CO)(Cl)H were obtained from Aldrich Chemicals Company, Inc., U.S.A. Solvents were dried before use. All the reactions were carried out under dry N 2 . The light petroleum used had b.p. 60-80°C.Methods: IR spectra (KBr) were recorded on a Perkin-Elmer 783 spectrometer and electronic spectra (CHCl 3 ) on a Shimadzu UV 190 spectrometer. 1 H NMR and 13 C NMR spectra were measured with a JEOL spectrometer model FX 900 FTNMR using TMS in DMSO-d 6 as internal standard.Chloride and phosphorus were estimated gravimetrically. C, H and N analyses were determined by a Perkin-Elmer model 240c elemental analyser.Preparation of complexes: All the reactions were carried out under dry dinitrogen. All the ruthenium (II) complexes were prepared by a similar procedure.The complex was prepared by the addition of the appropriate ligand suspended in 25ml methanol to a continuously stirred solution of 0.500 g [RuHCl(CO)(PPh 3 )] in 5 ml dichloromethane in 1:1 ratio under nitrogen atmosphere. The mixture was refluxed for 30 min, then allowed to cool, filtered off and the resulting solid was washed with methanol and finally with petroleum ether and dried under reduced pressure. Yields were 80-90 %.

Biological Study of Transition Metal Complexes with Adenine Ligand

“…Adenine (Ad) is one of four chemical bases in DNA as in Figure 1, with the other three being cytosine (C), guanine (G), and thymine (T). Within the DNA molecule, adenine bases located on one strand form chemical bonds with thymine bases on the opposite strand [9].…”