Synthesis, Characterization and Biological Evaluation of Mixed Ligand Complexes of Pt(IV), Pt(II) and Pd(II) Ions Containing Dibasic Acids and Heterocyclic Amines

A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry. Hossain entitled "Synthesis, characterization and biological evaluation of mixed ligand complexes of Pt(11"), P1(11) and Pd('II) ions containing dibasic and heterocyclic a,nine acids" has been approved by the board of examiners in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry, Khulna University of Engineering &.

Contents

Page

Yousuf, "Synthesis, characterization and antibacterial studies of the mixed ligand complexes of Pd(II) & Pt(II) ions with phthalic acid and heterocyclic amines". 34; Characterization and antibacterial studies of the mixed ligand complexes of Pd(II) ion with phthalic acid and heterocyclic amines” Journal of Engineering Science, Vol.

Figure 4.3.2(b) Possible ball and stick model of the complex-b, [Pd(ll)(Ph)(IQ)2] 59 Figure 4.3.3(a) Possible structure of the complex- I 1, [Pd(II)(Ph)(Py)2] 60 Figure 4.3.3(b) Possible ball and stick model of the complex-I 1, [Pd(11)(Ph)(Py)2] 60

Introduction

The Mixed Ligand Metal Complex 1.2 Carboxylato Ligands

Heterocyclic Amine Ligands 1.4 Biologically Active Ligands

Introduction

The Mixed Ligand Metal Complex
Carboxylato Ligands
Heterocyclic Amine Ligands

For example, the catalytic properties of vitamin B12 and its coenzyme are due to the ability of the cobalt ion to act as a storehouse for an electron that can be released or accepted as needed. The metal ion in natural macrocyclic complexes is trapped in such a complex structure that the fundamental properties of these metal ions are still not well understood.

Figure 1.2: Dibasic acids co-ordinet with metal ion

Literature survey

Previous Work 2.2 Aim of the Work

An exhaustive survey of the existing literature reveals that very little has been done on the metal complexes of malonic &. In the second part of the research project, they isolated and characterized a new type of pyrimidine-bridged binuclear complexes with sulfoxide ligands50.

Aim of the Work

In the present investigation heterocyclic arnines were used in most cases as secondary ligands. Chapter Two The literature survey W 12 included in this thesis deals with the interaction of some organic ligands with metal ions and antibacterial studies have been carried out there.

Chemicals

General Method for Synthesis of the Complexes 3.3 Physical Measurements

Weighing
Melting Point Measurement 3.3.3 Conductivity Measurement
Analysis for Carbon, Hydrogen and Nitrogen 3.4.2 Determination Palladium (II)
Determination of Platinum 3.4.4 Infrared Spectra
Electronic Spectra 3.5 Antibacterial Activity
Preparation of fresh culture 3.5.3 Preparation of plates
Preparation of discs
Placement of the discs and incubation 3.5.6 Calculation of the zone of inhibition
Synthesis of Mixed Ligand Complexes of Pt (IV) Ion with Malonic Acid and Heterocyclic Arnines (complex
Synthesis of Mixed Ligand Complexes of Pt (IV) Ion with Oxalic Acid and Heterocyclic Amines (complex
Synthesis of Mixed Ligand Complexes of Pd (II) and Pt (TI) Ions with Phthalic Acid and Heterocyclic

An ethanolic solution of Pt(Il), Pt(IV) and Pd(II) ions and dibasic acids (MAH2 OXH2, PhH2) was mixed in the calculated ratio under constant stirring. The volume of the solution was reduced by half and allowed to cool to room temperature slowly.

Table 3.1: List of Chemicals used No Name of the

Physical Measurements .1 Weighing

Melting Point Measurement
Conductivity Measurement
Magnetic Measurements
Analysis for Carbon, Hydrogen and Nitrogen
Determination Palladium (II)
Determination of Platinum
Infrared Spectra
Electronic Spectra

A known weight (about 0.2 g) of the Pd complex was treated with concentrated H2SO4 (5 cm3) and concentrated l-1NO3 (20 cm3) and the mixture was evaporated at. A known weight (about 0.05 g) of the Pt complex was treated with concentrated H2SO4 (5 cm3) and concentrated l-1NO3 (20 cm3) and the mixture was evaporated to dryness.

Table 3.3: Pascal's constant for the elements and molecules Elements/Molecules Pascal's Const

Antibacterial Activity

Culture media
Synthesis of Mixed Ligand Complexes of Pt (IV) Ion with Malonic Acid and Heterocyclic Amines (complex 1-4)
Synthesis of Mixed Ligand Complexes of Pt (IV) Ion with Oxalic Acid and Heterocyclic Amines (complex 5-8)
Synthesis of Mixed Ligand Complexes of Pd (II) Ion with Oxalic Acid and Heterocyclic Amines (complex 14-17)

In a typical transition metal complex, the observed spectrum generally consists of a series of crystal field bands which are in the visible region and depend on the donor atom of the ligand and the metal ion. After incubation, the diameter of the zone of inhibition was observed and measured in mm with a transparent scale. A 25 ml ethanolic solution of the metal salt (PtH2Cl6) 0 mmol) and 30 ml ethanolic solution of malonic acid (2 mmol) (for complex 1-4) were mixed with continuous stirring.

The volume of the solution is reduced to half and allowed to slowly cool to room temperature. With constant stirring, 25 mL of an ethanolic solution of the metal salt (PtH206) (1 mmol) and 30 mL of an ethanolic solution of oxalic acid (2 mmol) were mixed (for complex 5-8). 25 mL of an ethanolic solution of the metal salt (PdCl2) (1 mmol) and 30 mL of an ethanolic solution of oxalic acid (1 mmol) (for complex 14-17) were mixed under constant stirring.

Results and Discussion 1

Characterization of Mixed Ligand Complexes of Pt (IV) Ion with Ma Ionic Acid and Heterocyclic Amines [Complex 1-41

Solubility
Color & Melting point 4.1.1.3 Conductivity Measurement
Infrared Spectra Studies 4 1 4 Electronic Spectra Studies
Physical Properties .1 Solubility

Color & Melting point
Magnetic Moment Measurement

Elemental Analysis
Electronic Spectra Studies

The conductivity values of the complexes were in the range of fi' cm2 rnole' showed that these complexes are non-electrolytic in nature." The conductivity values are given in Table 4.1.2. The magnetic moment values of the synthesized complexes showed that these complexes are diamagnetic (Table 4.1 .2) Elemental analyzes of synthesized mixed ligand complexes were performed for platinum, carbon, hydrogen and nitrogen.

The presence of M—N bonding in the complexes is evident from the appearance of 1'N modes at ciii' in the spectra of the complexes. The review of the existing literature shows that the complexes of 5d6 metal ions are generally diamagnetic in nature. From the above discussion, it is clear that the synthesized Pt(IV) complexes are Octahedral in structure and the probable structures of the complexes are shown in figures.

Table 4.1.1: Solubility of the synthesized complexes

Physical Properties .1 Solubility

Infrared Spectra Studies 4.2.4 Electronic Spectra Studies

Solubility
Color & Melting point

Elemental Analysis
Infrared Spectra Studies
Electronic Spectra Studies

The magnetic moment values of the synthesized complexes indicated that these complexes are diamagnetic (Table 4.2.2). It can be seen that the analytical data are in good agreement with the proposed empirical formula for the present complexes. The magnitude of the separation between these two bands [A(OCO) cm'] has been used, tentatively, as an aid in determining the nature of the carboxylate coordination”8.

Characterization of the coordination mode of carboxylates based on the JR spectrum of the metal complex has been previously discussed by Deacon and Philips'. In and out planar ring deformation modes of heterocyclic amines observed in . The presence of the M-N bond in the complexes is evident from the appearance of VMN modes at cm' in the spectra of the complexes.

Table 4.2.1: Solubility of the synthesized complexes

Results and Discussion 3

Characterization of Mixed Ligand Complexes of Pd (II) & Pt(II) Ion with Phthalic Acid and Heterocyclic Amines [Complex 9-13]

Physical Properties .1 Solubility

Infrared Spectra Studies 4.3.4 Electronic Spectra Studies

Chapter Four Results and Discussion Q 53 shows a strong indication of ligand coordination and complex formation. The values of the magnetic moment of the synthesized complexes showed that these complexes are diamagnetic (Table 4.3.2).

Physical Properties .1 Solubility

Elemental analyzes of the synthesized mixed ligand complexes were performed for palladium, platinum, carbon, hydrogen, and nitrogen. Microanalysis of carbon, hydrogen and nitrogen was carried out with an organic elemental analyzer.

Table 4.3.3: Elemental analyses of the complexes

Infrared Spectra Studies

The characteristic ring vibration of the heterocyclic amines in the range 1400-1600 cm1 generally shows significant changes in complexation, but in our present complexes these bands could not be distinguished due to overlap with vc=o and vc stretching bands. The in-plane and out-of-plane ring deformation modes of the heterocyclic amines observed at -520 and -720 cm, respectively, undergo a positive shift in mixed ligand complexes, thereby adapting to a coordination through nitrogen. The presence of M-N bonding in the complexes is evident from the appearance of VMN states at cm 1.

The spectra of the Pd(I1) complex in DMSO showed three spin-allowed dd transitions and two charge transfer bands. All these bands are characteristic of a square Pt(ll) complex. Electronic spectral data for the Pt(ll) complexes are given in Table 4.3.6. From the above discussion, it is clear that the synthesized Pd(ll) and Pt(ll) complexes have a square planar structure and the probable structures of the complexes are shown in figures.

Table 4.3.5: Electronic spectral data (cni') of square-planar palladium (II) complexes Complex Spectral band (cm) with assignment

Physical Properties .1 Solubility

Elemental Analysis 4.4.3 Infrared Spectra Studies

Characterization of Mixed Ligand Complexes of Pd(II) Ion with Oxalic Acid and Heterocyclic Amines ICComplex 14-171 .. Chapter Four Results and DiscussionU 64 temperature and pressure). The complexes were all sparingly soluble in water and methanol, but soluble in DMF and DMSO (table 4.4.1). The melting point of complex-14, Pd(Il)(OX)(Q)2 is 270±5°C while the melting point of the ligands, oxalic acid is 102-103°C and quinoline is -15°C indicating the potency . indicative of ligand coordination and complex formation.

Results and Discussion The 65 complexes were non-electrolyte in nature& !'• Conductivity values are given in Table 4.4.2. The values of the magnetic moment of the synthesized complexes showed that these complexes are diamagnetic (table 4.4.2).

Table 4.4.1: Solubility of the synthesized complexes

Elemental Analysis

The position of the strong C=O absorption band in the carboxylic acid group of the free carboxylic acid of oxalic acid, 1692.6 and 1441.8 cm'. The magnitude of the separation between these two bands [A(OCO)cin-11 has been used, tentatively, as an aid in determining the nature of the carboxylate coordination"8. Characterization of the carboxylate coordination state based on the IR spectrum of the metal complex has previously been discussed by Deacon and Philips."

This large difference in energy is believed to be due to the bonding of one oxygen atom to the metal with another non-oxygen atom, increasing the energy of the asymmetric stretching mode. Tentative assignments for the coordination modes of carboxylate ligands (oxalate) with Pd(II) based on A(OCO) values are listed in Table 4.4.4. The characteristic ring vibration of heterocyclic amines in the 1400-1600 cm 1 range generally shows significant changes upon complexation, but in our present complexes these bands could not be distinguished due to overlap with the VC=O and VC.O stretching bands.

Table 4.4.3: Elemental analyses of the complexes

Electronic Spectra Studies

Antibacterial Screening

The complexes containing 2-aminopyridine and 4-picoline as secondary ligands are much more microbially active than the other complexes. Moreover, the complexes [Pt(MA)2(4-pico)2] showed the highest antibacterial activity against all bacteria tested. Complexes 2, 7 and 11 were found to have no zone inhibition against Staphylococcus aureus, Salmonella typhi and Salmonella bovismorb?ficans.

Among the tested complexes, all showed more or less antibacterial activities against the treated bacteria. The highest and the lowest antibacterial activities were found in complex 4 and complex 11 respectively against all the treated bacteria. It can be concluded that from the data, most of the complexes are found to be effective antibacterial agent.

IIII

1III!

Figure- 4.5.9: Photographic Figure- 4.5.10: Photographic representation of inhibition zone of inhibition zone of complexes 11, 12 and 13 respectively complexes 14 and 15 respectively vs.

Table 4.5.3: Antibacterial activity of the complexes (9-13)

Conclusion 5. Conclusion

Y Synthesis and Characterization of Mixed Ligand Complexes of Co(II) and Fe(III) Ions with Malonic Acid and Heterocyclic Amines". A Synthesis and Characterization of Mixed Ligand Complexes of Co(II) and Fe(III) Ions with Acids Maleic and Heterocyclic Amines". S Synthesis and Characterization of Mixed Ligand Complexes of Pt(IV) and Ni(Il) Ions with Phthalic Acid and Heterocyclic Amines”.

U Mixed ligand complexes of copper(II) palladium(11) and platinum(IV) with homophthalic acid and heterocyclic bases". Mixed ligand complexes of Co(II) and Ni(II) with diphenic acid as primary and heterocyclic bases as secondary Ligands". 2009, "Antifungal Activity of Mixed Ligand Transition Metal Complexes of Some Dibasic Acids and Heterocyclic Bases".