**From Synthesis to Antibacterial Activity of Some New Palladium(II) and Platinum(IV) Complexes**

Ivana D. Radojević1, Verica V. Glođović2, Gordana P. Radić2, Jelena M. Vujić3, Olgica D. Stefanović1, Ljiljana R. Čomić1 and Srećko R. Trifunović<sup>2</sup> *1Department of Biology and Ecology, Faculty of Science, University of Kragujevac, Kragujevac, 2Department of Chemistry, Faculty of Science, University of Kragujevac, Kragujevac, 3Faculty of Agronomy, University of Kragujevac, Čačak, Republic of Serbia* 

#### **1. Introduction**

310 Antimicrobial Agents

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The synthesis and evaluation of the biological activity of the new metal-based compounds is the field of growing interest. Numerous complexes based on palladium(II) and platina(IV) ion have been synthesized and their different biological activities have been documented (Agarwal, 2007; Mishra et al., 2007a; Mishra & Kaushik, 2007). The impact of different palladium and platinum complexes on the growth and metabolism of various groups of microorganisms has been studied. Garoufis et al. (2009) reviewed numerous scientific papers on anti-viral, antibacterial and antifungal activity of palladium(II) complexes with different types of ligands (sulfur and nitrogen donor ligands, Schiff base ligands and drugs as ligands). There are other papers in the literature showing different intensity of palladium(II) and platina(IV) complexes activity on various species of bacteria and fungi (Kovala-Demertzi et al., 2001; Brudzinska et al., 2004; Coombs et al., 2005; Guerra et al., 2005; Ali et al., 2006; Manav et al., 2006; Aghatabay et al., 2007; Kizilcikli et al., 2007; Mishra et al., 2007b; Biyala et al., 2008; Al-Hazmi et al., 2008; Vieira et al., 2009).

The aim of this paper is to describe synthesis of some new palladium(II) and platinum(IV) complexes and in vitro research of their antibacterial activities. The second objective is to evaluate the impact these compounds have on probiotic bacteria. Probiotics are used as supplements and they play significant role in protecting and maintaining the balance of intestinal microflora in antibiotic therapy.

From Synthesis to Antibacterial




platinum(IV) (**L17b**)

platinum(IV)(**C18**)

platinum(IV) (**C19**)

platinum(IV) (**C20**)

platinum(IV) (**C21**)

**complexes – C1, C2, C3** 

air dried (Vasić et al., 2010) (Fig. 1.).

**complexes – C4, C5, C6, C7** 

and air-dried.

(**L17a**)







Activity of Some New Palladium(II) and Platinum(IV) Complexes 313







**2.1.1 The synthesis of the ligands - L1, L2, L3 and corresponding palladium(II)** 

In 50 mL of dry alcohol (1-propanol, 1-butanol or 1-pentanol), saturated with gas HCl, 1.53 g (7.5 mmol) of H2-*S,S*-eddp was added and the mixture was refluxed for 12 h. The mixture was filtered and left in the refrigerator over night. The obtained white powder was filtered

Complexes were obtained by mixing K2[PdCl4] (0.200 g, 0.613 mmol) and equimolar amount of the dpr-*S,S*-eddp·2HCl·3H2O (**L1**) (0.2546 g, 0.613 mmol), dbu-*S,S*-eddp·2HCl·3H2O (**L2**) (0.2718 g, 0.613 mmol) or dpe-*S,S*-eddp·2HCl·2H2O (**L3**) (0.2780 g, 0.613 mmol) esters. During 2 h of stirring 10 cm3 of water solution of LiOH (0.0294 g, 1.226 mmol) was added in small portions to the reaction mixture. Within this period, pale yellow precipitates of the complexes **C1-C3** were obtained, filtered off, washed with cold water, ethanol and ether and

**2.1.2 The synthesis of the ligands - L4, L5, L6, L7 and corresponding palladium(II)** 

The esters were recrystallized from hot alcohol used for each reaction.

In 50 mL of dry alcohol (ethanol, 1-propanol, 1-butanol or 1-pentanol), saturated with gas HCl, 2.50 g (7.5 mmol) of (H2-(*S,S*)-eddv) was added and the mixture was refluxed for 12 h. The mixture was filtered off and the filtrate was left for a few days in a refrigerator at 4°C.



