**2.1.2 The synthesis of the ligands - L4, L5, L6, L7 and corresponding palladium(II) complexes – C4, C5, C6, C7**

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

From Synthesis to Antibacterial

NH

+ ROH

HO

O

HO

O

complexes

NH

**complexes – C8, C9, C10 and C11** 

Activity of Some New Palladium(II) and Platinum(IV) Complexes 315

Thionyl choride (4 cm3, 55 mmol) was introduced into a flask containing 50 cm3 of corresponding ice cooled alcohol (ethyl, *n*-propyl, n-butyl or *n*-pentyl; anhydrous conditions) for 1 h. After addition of 2 g (5.54 mmol) [(*S,S*)-H4eddl]Cl2 the reaction mixture was refluxed for 16 h, filtered off and the filtrate was left for a few days in a refrigerator at

Complexes were obtained by mixing K2[PdCl4] (0.2 g, 0.61 mmol) and equimolar amount of the **L8**·H2O (0.267 g, 0.61 mmol), **L9**·H2O (0.277 g, 0.61 mmol), **L10**·H2O (0.301 g, 0.61 mmol) or **L11**·H2O (0.318 g, 0.61 mmol) esters. During 2 h of stirring 10 cm3 of water solution of LiOH (0.0293 g, 1.22 mmol) was added in small portions to the reaction mixture. Within this period, pale yellow precipitates of the complexes **C8-C11** were obtained, filtered off, washed with cold water, ethanol and ether and air dried (Vujić et al., 2010) (Fig.3.). The crystal

NH

2HCl SOCl2

NH

LiOH

K2[PdCl4]

RO

O

RO

R = Et(**C8**), *n*-Pr(**C9**), *n*-Bu(**C10**), *n*-Pe(**C11**)

O

N

Pd

H

H

Cl

Cl

N

R = Et(**L8**), *n*-Pr(**L9**), *n*-Bu(**L10**), *n*-Pe(**L11**)

Fig. 3. The preparation of some alkyl esters of H2-*S,S*-eddl and corresponding palladium(II)

The thioacid ligands (**L12**)-(**L16**) were prepared by alkylation of thiosalicylic acid by means

Thiosalicylic acid (1 mmol) was added to a 100 cm3 round bottom flask containing 50 cm3 of 30% solution of ethanol in water and stirred. A solution of NaOH (2 mmol in 5 cm3 of water) was added to acid suspension. The solution became clear. The corresponding alkyl halogenide (2 mmol) was dissolved in 5 cm3 of ethanol and transferred to the stirred solution. The resulting mixture was kept overnight at 60°C. The reaction mixture was

**2.1.4 The synthesis of the ligands - L12, L13, L14, L15, L16 and corresponding** 

of corresponding alkyl halogenides in alkaline water-ethanol solution.

4°C. The esters were recrystallized from the hot alcohol used for each reaction.

structure of **C11** was confirmed by X-ray analysis (Vujić, et al., 2011).

O

RO

RO

**palladium(II) complexes – C12, C13, C14, C15, C16** 

reflux 16h

O

**2.1.3 The synthesis of the ligands - L8, L9, L10, L11 and corresponding palladium(II)** 

Fig. 1. The preparation of some alkyl esters of H2-*S,S*-eddp and corresponding palladium(II) complexes

Complexes were obtained by mixing K2[PdCl4] (0.200 g, 0.613 mmol) and equimolar amount of the **L4** (0.241 g, 0.613 mmol), **L5** (0.256 g, 0.613 mmol), **L6** (0.273 g, 0.613 mmol) or **L7**  (0.290 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 **C4-C7** were obtained, filtered off, washed with cold water, ethanol and ether and air dried (Fig.2.). The crystal structure of C4 was confirmed by X-ray analysis (Radić et al., 2010b; 2011a).

Fig. 2. The preparation of some alkyl esters of H2-*S,S*-eddv and corresponding palladium(II) complexes

CH3

CH3

Fig. 1. The preparation of some alkyl esters of H2-*S,S*-eddp and corresponding palladium(II)

Complexes were obtained by mixing K2[PdCl4] (0.200 g, 0.613 mmol) and equimolar amount of the **L4** (0.241 g, 0.613 mmol), **L5** (0.256 g, 0.613 mmol), **L6** (0.273 g, 0.613 mmol) or **L7**  (0.290 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 **C4-C7** were obtained, filtered off, washed with cold water, ethanol and ether and air dried (Fig.2.). The crystal structure of C4 was

NH

CH

CH

LiOH

K2[PdCl4]

RO

R = Et(**L4**), *n*-Pr(**L5**), *n*-Bu(**L6**), *n*-Pe(**L7**)

Fig. 2. The preparation of some alkyl esters of H2-*S,S*-eddv and corresponding palladium(II)

NH

LiOH

K2[PdCl4]

RO

O

RO

R = *n*-Pr(**C1**), *n-*Bu(**C2**), *n*-Pe(**C3**)

O

N

CH3

H

H

R = Et(**C4**), *n*-Pr(**C5**), *n*-Bu(**C6**), *n*-Pe(**C7**)

O

CH

H

Pd

CH O

O

Cl

N

H

N

Pd

Cl

Cl

CH3

N

NH

RO

O

2HCl HCl

RO

confirmed by X-ray analysis (Radić et al., 2010b; 2011a).

RO

O

2HCl HCl

RO

O

O

R = *n*-Pr(**L1**), *n*-Bu(**L2**), *n*-Pe(**L3**)

NH

NH

CH3

+ ROH

CH3

HO

O

HO

O

complexes

HO

O

HO

O

complexes

NH

NH

CH

+ ROH

CH

NH

#### **2.1.3 The synthesis of the ligands - L8, L9, L10, L11 and corresponding palladium(II) complexes – C8, C9, C10 and C11**

Thionyl choride (4 cm3, 55 mmol) was introduced into a flask containing 50 cm3 of corresponding ice cooled alcohol (ethyl, *n*-propyl, n-butyl or *n*-pentyl; anhydrous conditions) for 1 h. After addition of 2 g (5.54 mmol) [(*S,S*)-H4eddl]Cl2 the reaction mixture was refluxed for 16 h, filtered off and the filtrate was left for a few days in a refrigerator at 4°C. The esters were recrystallized from the hot alcohol used for each reaction.

Complexes were obtained by mixing K2[PdCl4] (0.2 g, 0.61 mmol) and equimolar amount of the **L8**·H2O (0.267 g, 0.61 mmol), **L9**·H2O (0.277 g, 0.61 mmol), **L10**·H2O (0.301 g, 0.61 mmol) or **L11**·H2O (0.318 g, 0.61 mmol) esters. During 2 h of stirring 10 cm3 of water solution of LiOH (0.0293 g, 1.22 mmol) was added in small portions to the reaction mixture. Within this period, pale yellow precipitates of the complexes **C8-C11** were obtained, filtered off, washed with cold water, ethanol and ether and air dried (Vujić et al., 2010) (Fig.3.). The crystal structure of **C11** was confirmed by X-ray analysis (Vujić, et al., 2011).

Fig. 3. The preparation of some alkyl esters of H2-*S,S*-eddl and corresponding palladium(II) complexes

#### **2.1.4 The synthesis of the ligands - L12, L13, L14, L15, L16 and corresponding palladium(II) complexes – C12, C13, C14, C15, C16**

The thioacid ligands (**L12**)-(**L16**) were prepared by alkylation of thiosalicylic acid by means of corresponding alkyl halogenides in alkaline water-ethanol solution.

Thiosalicylic acid (1 mmol) was added to a 100 cm3 round bottom flask containing 50 cm3 of 30% solution of ethanol in water and stirred. A solution of NaOH (2 mmol in 5 cm3 of water) was added to acid suspension. The solution became clear. The corresponding alkyl halogenide (2 mmol) was dissolved in 5 cm3 of ethanol and transferred to the stirred solution. The resulting mixture was kept overnight at 60°C. The reaction mixture was

From Synthesis to Antibacterial

O

H

benzaldehyde ammonium acetate

H2N

Cl

HO

<sup>+</sup> ONH4

NH2

O

HN

OH <sup>O</sup>

(**L17**) *meso*-1,2-diphenyl-*N,N`*-di-3-propionic acid, dpheddp, 23,40%

K2PtCl6 LiOH

NH

Pt

Cl

Cl

Cl

O

OH

Cl

O

OH


NH

C14H16N2 t.t.=120,5-121,5 C

+

2 OH

N H H2 C C

H2 C

O

Activity of Some New Palladium(II) and Platinum(IV) Complexes 317

refluxed

Et2O

extraction

O

K2PdCl4 LiOH

(**C17b**)

Fig. 5. Reaction pathways in synthesis of *meso*-1,2-diphenyl-ethylenediamine-*N,N'-*di-3-

H2C

70% H2SO4

60%,C28H24ON2,mp=258-259 C

N NH

*N*-benzoyl-*N*`-benzylidene-*meso*-1,2-diphenylenediamine,

NaOH

N

Pd

H

H

Cl

O

OH

Cl

O

OH

N

(**C17a**)

<sup>C</sup> <sup>O</sup>

refluxed 1-2 hour

transferred into a beaker and ethanol was evaporated off on a water bath. Diluted hydrochloric acid (2 mol/dm3) was added to the resulting water solution and S-alkyl thiosalicylic acid was precipitated as a white powder. The liberated acid was filtered off and washed with plenty of distilled water. The product was dried under vacuum overnight.

Fig. 4. The preparation of alkyl eters of 2-thiosalicylic acid and corresponding palladium(II) complexes

K2[PdCl4] (0.100 g, 0.3065 mmol) was dissolved in 10 cm3 of water on a steam bath and (S-benzyl)-2-thiosalicylic acid (0.1497 g, 0.613 mmol), (S-methyl)-2-thiosalicylic acid (0.103 g, 0.613 mmol), (S-ethyl)-2-thiosalicylic acid (0.1117 g, 0.613 mmol), (S-propyl)-2-thiosalicylic acid (0.1203 g, 0.613 mmol) or (S-butyl)-2-thiosalicylic acid, (0.1289 g, 0.613 mmol) was added into the solution. The resulting mixture was stirred for 2h and during this time an aqueous solution of LiOH (0.0256 g, 0.613 mmol in 10 cm3 of water) was introduced. The complexes (**C12- C16**) as a yellow precipitate were filtered, washed with water and air-dried (Radić et al., 2011) (Fig.4.). The crystal structure of **C12** was confirmed by X-ray analysis (Dimitrijević et al., 2011).

#### **2.1.5 The synthesis of the ligand L17 and corresponding palladium(II) complex C17 and corresponding platinum(IV) complex C17a**

Benzaldehyde (30 g) was refluxed with ammonium acetate (60 g) for 3 hours. The reaction mixture was cooled and the product was filtered and washed with ethanol. Recrystallization from 1-butanol gave *N*-benzoyl-*N*'-benzylidene-*meso*-1,2-diphenyl-ethylendiamine. Hydrolysis of that compound with 70% sulphuric acid under reflux for 1h gave *meso*-1,2- -diphenyl-ethylenediamine as the basic product of hydrolysis.

3-Chloro-propanoic acid (4.34 g, 0.04 mol) was dissolved in 5 cm3 of water on ice bath and carefully neutralized with cold water solution of 5 cm3 NaOH (1.6 g, 0.04 mol). 1,2- Diphenyl--ethylenediamine (4.24 g, 0.02 mol) was added to this solution. The mixture was being stirred for 4 hours at 90°C, and during this period 5 cm3 NaOH water solution (1.6 g, 0.04 mol) was introduced. After that, 5.6 cm3 6 mol/dm3 HCl was added and resulting solution was evaporated to the volume of 7 cm3; 6 cm3 *conc.* HCl, 6 cm3 of ethanol and 6 cm3 of ether were added to the mixture. The white precipitate of H2 -1,2-dpheddp·2HCl·1.5H2O (**L17**) was separated by filtration and refined with solution water : ethanol = 1 : 2. The crystal structure of **L17** was confirmed by X-ray analysis (Radić et al., 2010a).

transferred into a beaker and ethanol was evaporated off on a water bath. Diluted hydrochloric acid (2 mol/dm3) was added to the resulting water solution and S-alkyl thiosalicylic acid was precipitated as a white powder. The liberated acid was filtered off and washed with plenty of distilled water. The product was dried under vacuum overnight.

C O OH

complexes

R-X Ethanol/H2O

2NaOH,

(Dimitrijević et al., 2011).

C O ONa

**and corresponding platinum(IV) complex C17a** 


structure of **L17** was confirmed by X-ray analysis (Radić et al., 2010a).

R H+

C O OH

R= Benzy(**L12**), methyl(**L13**), ethyl(**L14**), propyl(**L15**), butyl(**L16**)

Fig. 4. The preparation of alkyl eters of 2-thiosalicylic acid and corresponding palladium(II)

K2[PdCl4] (0.100 g, 0.3065 mmol) was dissolved in 10 cm3 of water on a steam bath and (S-benzyl)-2-thiosalicylic acid (0.1497 g, 0.613 mmol), (S-methyl)-2-thiosalicylic acid (0.103 g, 0.613 mmol), (S-ethyl)-2-thiosalicylic acid (0.1117 g, 0.613 mmol), (S-propyl)-2-thiosalicylic acid (0.1203 g, 0.613 mmol) or (S-butyl)-2-thiosalicylic acid, (0.1289 g, 0.613 mmol) was added into the solution. The resulting mixture was stirred for 2h and during this time an aqueous solution of LiOH (0.0256 g, 0.613 mmol in 10 cm3 of water) was introduced. The complexes (**C12- C16**) as a yellow precipitate were filtered, washed with water and air-dried (Radić et al., 2011) (Fig.4.). The crystal structure of **C12** was confirmed by X-ray analysis

**2.1.5 The synthesis of the ligand L17 and corresponding palladium(II) complex C17** 

Benzaldehyde (30 g) was refluxed with ammonium acetate (60 g) for 3 hours. The reaction mixture was cooled and the product was filtered and washed with ethanol. Recrystallization from 1-butanol gave *N*-benzoyl-*N*'-benzylidene-*meso*-1,2-diphenyl-ethylendiamine. Hydrolysis of that compound with 70% sulphuric acid under reflux for 1h gave *meso*-1,2-

3-Chloro-propanoic acid (4.34 g, 0.04 mol) was dissolved in 5 cm3 of water on ice bath and carefully neutralized with cold water solution of 5 cm3 NaOH (1.6 g, 0.04 mol). 1,2- Diphenyl--ethylenediamine (4.24 g, 0.02 mol) was added to this solution. The mixture was being stirred for 4 hours at 90°C, and during this period 5 cm3 NaOH water solution (1.6 g, 0.04 mol) was introduced. After that, 5.6 cm3 6 mol/dm3 HCl was added and resulting solution was evaporated to the volume of 7 cm3; 6 cm3 *conc.* HCl, 6 cm3 of ethanol and 6 cm3 of ether were added to the mixture. The white precipitate of H2 -1,2-dpheddp·2HCl·1.5H2O (**L17**) was separated by filtration and refined with solution water : ethanol = 1 : 2. The crystal

S R

K2PdCl4

LiOH

Pd

R R

R= Benzy(**C12**), methyl(**C13**), ethyl(**C14**), propyl(**C15**), butyl(**C16**)

S

O C

O

S

C O

O

SH S

Fig. 5. Reaction pathways in synthesis of *meso*-1,2-diphenyl-ethylenediamine-*N,N'-*di-3- -propionic acid and corresponding palladium(II) and platinum(IV) complexes.

From Synthesis to Antibacterial

NH

CH

C CH3

NH

CH

C CH3

**complexes C19, C20, C21** 

H2C

O

HO

HO

H2C

O

air-dried.

2010).


H

H2-*S,S*-eddba

Activity of Some New Palladium(II) and Platinum(IV) Complexes 319

NH

K2PtCl6 LiOH

H3C

H3C

(**L18**) (**C18**)

O

H

H

NH

Pt

Cl Cl

Cl

Cl

CH

C CH3

CH

C CH3

H2C

O

O

O

C H2

H2C

H2C NH

O

N+ OR

Cl <sup>H</sup> -

N+

Cl-

H

R = ethyl (**L19**), propyl (**L20**), butyl (**L21**)

O

CH

C CH3

NH

CH

C CH3

H2C

O

O

O

Fig. 7. Synthesis of the ester det-(*S,S*)-eddp·2HCl and platinum(IV) complex

C H2

H2C

H3C

CH3CH2OH HCl

N O-

N

H

O

H3C

H2C

O

**2.1.7 The synthesis of the ligands L19, L20, L21 and corresponding platinum(IV)** 

In 50 cm3 of dry alcohol (ethanol, 1-propanol, 1-butanol) saturated with gaseous HCl, 1.50 g (3.65 mmol) of ethylenediamine-*N,N'*-di-*S,S*-(2,2ʹ-dibenzyl)acetate acid threehydrate (H2*-S,S*-eddba·3H2O) 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 and

K2[PtCl6] (0.100 g, 0.206 mmol) and 0.206 mmol of R2-*S,S*-eddba·2HCl (0.100 g of de-*S,S*- -eddba·2HCl (**L19**), 0.106 g of dp*-S,S*-eddba·2HCl (**L20**), 0.112 g of db*-S,S*-eddba·2HCl (**L21**)) were dissolved in 15 cm3 of water. The reaction mixture was heated at 40 °C for 12 h and during this period 3.92 cm3 of aqueous 0.105 mol/dm3 LiOH·H2O (0.412 mmol) were added in small portions The complexes (**C19**-**C21**) as a yellow-orange precipitates were collected by filtration, washed with water, corresponding alcohol and ether and air-dried (Fig. 8.). The crystal structure of **L20** was confirmed by X-ray analysis (Dimitrijević et al.,

RO + 2 ROH HCl(g)

a)

Potassium-hexachloridoplatinate(IV) (0.2 g, 0.411 mmol) was dissolved in 10 cm3 of water on a steam bath and 1,2-diphenyl-ethylenediamine-*N,N'*-di-3-propanoic acid (0.1876 g, 0.411 mmol) was added. The reaction mixture was heated for 12 hours and during this period 10 cm3 of LiOH water solution (0.0394 g, 1.65 mmol) was added in small portions and the solution was filtered and evaporated to small volume. The orange precipitate of *s-cis*- [PtCl2(1,2-dpheddp)] **C17b**) was separated by filtration, washed with cold water and airdried (Fig. 5).

#### **2.1.6 The synthesis of the ligands L4, L18 and corresponding platinum(IV) complexes C4a, C18**

K2[PtCl6] (0.100 g, 0.205 mmol) and det-(*S,S*)-eddv (0.080 g, 0.205 mmol) were dissolved in 25 cm3 of water. The reaction mixture was heated on a steam bath for 3 h during which water solution of LiOH·H2O (0.017 g, 0.41 mmol in 10 cm3 of water) was introduced. The complex, [PtCl4(det-(*S,S*)-eddv)] (**C4a**), as a yellow precipitate was separated by filtration, washed with water and air-dried (Fig. 6.).

In 50 cm3 of dry ethanol, 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 of *O,O'*-diethyl-(*S,S*)- -ethylenediamine-*N,N'*-di-2-propanoate dihydrochloride, det-*S,S*-eddp·2HCl (**L18**) was filtered and air dried.

K2[PtCl6] (0.100 g, 0.205 mmol) and det-(*S,S*)-eddp (0.068 g, 0.205 mmol) were dissolved in 25 cm3 of water. The reaction mixture was heated on a steam bath for 3 h during which water solution of LiOH·H2O (0.017 g, 0.41 mmol in 10 cm3 of water) was introduced. The complex, [PtCl4(det-(*S,S*)-eddp)] (**C18**), as a yellow precipitate was separated by filtration, washed with water and air-dried (Stanković et al., 2011b) (Fig. 7.). The crystal structure of **C18** was confirmed by X-ray analysis (Stanković et al., 2011b).

Fig. 6. Synthesis of the ester det-(*S,S*)-eddv·2HCl and platinum(IV) complex

Potassium-hexachloridoplatinate(IV) (0.2 g, 0.411 mmol) was dissolved in 10 cm3 of water on a steam bath and 1,2-diphenyl-ethylenediamine-*N,N'*-di-3-propanoic acid (0.1876 g, 0.411 mmol) was added. The reaction mixture was heated for 12 hours and during this period 10 cm3 of LiOH water solution (0.0394 g, 1.65 mmol) was added in small portions and the solution was filtered and evaporated to small volume. The orange precipitate of *s-cis*- [PtCl2(1,2-dpheddp)] **C17b**) was separated by filtration, washed with cold water and air-

**2.1.6 The synthesis of the ligands L4, L18 and corresponding platinum(IV) complexes** 

K2[PtCl6] (0.100 g, 0.205 mmol) and det-(*S,S*)-eddv (0.080 g, 0.205 mmol) were dissolved in 25 cm3 of water. The reaction mixture was heated on a steam bath for 3 h during which water solution of LiOH·H2O (0.017 g, 0.41 mmol in 10 cm3 of water) was introduced. The complex, [PtCl4(det-(*S,S*)-eddv)] (**C4a**), as a yellow precipitate was separated by filtration,

In 50 cm3 of dry ethanol, 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 of *O,O'*-diethyl-(*S,S*)- -ethylenediamine-*N,N'*-di-2-propanoate dihydrochloride, det-*S,S*-eddp·2HCl (**L18**) was

K2[PtCl6] (0.100 g, 0.205 mmol) and det-(*S,S*)-eddp (0.068 g, 0.205 mmol) were dissolved in 25 cm3 of water. The reaction mixture was heated on a steam bath for 3 h during which water solution of LiOH·H2O (0.017 g, 0.41 mmol in 10 cm3 of water) was introduced. The complex, [PtCl4(det-(*S,S*)-eddp)] (**C18**), as a yellow precipitate was separated by filtration, washed with water and air-dried (Stanković et al., 2011b) (Fig. 7.). The crystal structure of

NH

K2PtCl6 LiOH

H3C

H3C

NH

Pt

Cl Cl

Cl

CH3

Cl

H3C CH3

CH

C CH

CH

C CH

H3C

H2C

O

O

O

C H2

(**L4**) (**C4a**)

H2C

H2C NH

O

CH

C CH

H3C CH3

NH

CH

C CH

H3C CH3

H2C

O

O

O

Fig. 6. Synthesis of the ester det-(*S,S*)-eddv·2HCl and platinum(IV) complex

C H2 H2C

O

dried (Fig. 5).

filtered and air dried.

NH

CH

C CH

H3C

NH

CH

C CH

H3C

H2C

O

HO

HO

H2C

O

washed with water and air-dried (Fig. 6.).

**C18** was confirmed by X-ray analysis (Stanković et al., 2011b).

H2C

H3C

CH3CH2OH HCl

CH3

CH3

H3C

**C4a, C18** 

Fig. 7. Synthesis of the ester det-(*S,S*)-eddp·2HCl and platinum(IV) complex

#### **2.1.7 The synthesis of the ligands L19, L20, L21 and corresponding platinum(IV) complexes C19, C20, C21**

In 50 cm3 of dry alcohol (ethanol, 1-propanol, 1-butanol) saturated with gaseous HCl, 1.50 g (3.65 mmol) of ethylenediamine-*N,N'*-di-*S,S*-(2,2ʹ-dibenzyl)acetate acid threehydrate (H2*-S,S*-eddba·3H2O) 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 and air-dried.

K2[PtCl6] (0.100 g, 0.206 mmol) and 0.206 mmol of R2-*S,S*-eddba·2HCl (0.100 g of de-*S,S*- -eddba·2HCl (**L19**), 0.106 g of dp*-S,S*-eddba·2HCl (**L20**), 0.112 g of db*-S,S*-eddba·2HCl (**L21**)) were dissolved in 15 cm3 of water. The reaction mixture was heated at 40 °C for 12 h and during this period 3.92 cm3 of aqueous 0.105 mol/dm3 LiOH·H2O (0.412 mmol) were added in small portions The complexes (**C19**-**C21**) as a yellow-orange precipitates were collected by filtration, washed with water, corresponding alcohol and ether and air-dried (Fig. 8.). The crystal structure of **L20** was confirmed by X-ray analysis (Dimitrijević et al., 2010).

H2-*S,S*-eddba

From Synthesis to Antibacterial

**3. Results and discussion** 

the growth of the tested microorganisms.

Activity of Some New Palladium(II) and Platinum(IV) Complexes 321

with resazurin (Sarker et al., 2007). The 96-well plates were prepared by dispensing 100 μL of nutrient broth into each well. A 100 μL from the stock solution of tested compound (concentration 2000 μg/mL) was added into the first row of the plate. Then, twofold, serial dilutions were performed by using a multichannel pipette. The obtained concentration range was from 1000 μg/mL to 7.81 μg/mL. A 10 μL of diluted bacterial suspension was added to each well to give a final concentration of 5 x 105 CFU/mL. Finally, 10 μL resazurin solution was added to each well inoculated with bacteria. Resazurin is an oxidation– reduction indicator used for the evaluation of microbial growth. It is a blue non-fluorescent dye that becomes pink and fluorescent when reduced to resorufin by oxidoreductases within viable cells (Banfi et al., 2003). The inoculated plates were incubated at 37 °C for 24 h. MIC was defined as the lowest concentration of the tested substance that prevented resazurin color change from blue to pink. Doxycycline was used as a positive control. Solvent control test was performed to study an effect of 10% DMSO on the growth of microorganism. It was observed that 10% DMSO did not inhibit the growth of microorganism. Also, in the experiment, the concentration of DMSO was additionally decreased because of the twofold serial dilution assay (the working concentration was 5% and lower). Each test included growth control and sterility control. All tests were performed in duplicate and MICs were constant. Minimum bactericidal concentration was determined by plating 10 μL of samples from wells, where no indicator color change was recorded, on nutrient agar medium. At the end of the incubation period the lowest concentration with no

growth (no colony) was defined as minimum bactericidal concentration.

noticed and, in general, the most active were palladium(II) complexes.

these concentrations: 7.81 μg/mL, 15,63 μg/mL and <7.81 μg/mL.

The results of *in vitro* testing of antibacterial activities of the ligands and corresponding palladium(II) and platinum(IV) complex are shown in Table 1-10. For comparison, MIC and MBC values of doxycycline are listed in Table 11. The solvent (10% DMSO) did not inhibit

The intensity of antimicrobial action varied depending on the species of microorganism and on the type and concentration of tested compounds. The difference between antimicrobial activity of the ligands and corresponding palladium(II) and platinum(IV) complexes is

The results of antibacterial testing for the ligands (**L1, L2, L3**) and corresponding palladium(II) complexes (**C1, C2, C3**) are shown in Table 1. The results for 3 strains of pathogenic bacteria and 2 species of probiotic bacteria were reported in the paper Vasić et al., (2010). Results for *S. enterica*, *Staphyl. aureus* ATCC 25923, *S. lutea* ATCC 9341 and *L. rhamnosus* were first presented in this paper. These ligands and complexes, being compared to positive control, showed low to moderate antibacterial activity. MIC and MBC values were in range from <7.81 to >1000 μg/mL, depending on the species of bacteria. Grampositive bacteria showed higher sensitivity. The most sensitive was *S. lutea* ATCC 9341, where MIC was for **C1** and **C2** <7.81 μg/mL. The best activity at Gram-negative bacteria was shown by **C2** to *P. aeruginosa* ATCC 27853 and *E. coli* (MIC was 31.25 μg/mL). The probiotics showed sensitivity similar to the sensitivity of the other bacteria to the tested compounds. Exception is *B. animalis subsp. lactis* where **L2**, **C2** and **L3** inhibited its growth at

Fig. 8. The synthesis of: a) esters (R2-*S,S*-eddba·2HCl); b) complexes [PtCl4(R2-*S,S*-eddba)]
