GENERAL INTRODUCTION - BUET Central Library

INTRODUCTION

The modern study of coordination compounds begins with two famous men, Alfred Werner and Sophus Mads Joargensen. In fact, he was the founder of modern coordination chemistry, setting up the first successful theory known as "Werner's coordination theory" to explain the formation, properties and stereochemistry of coordination compounds.

CLASSIFICATION OF LIGANDS

Unidentate Ligands
Bidentated Ligands
Tridentate Ligands
Tetradentate ligands
Bridging Ligand
Non-innocent Ligand
Bulky Ligand
Strong Field and Weak Field Ligands
Tetra Azamacrocyclic Ligands

According to molecular orbital theory, the HOMO of the ligand must have an energy that overlaps with the lowest unoccupied molecular orbital (LUMO) of the preferred metal. Metal ions with preferred coordination numbers > 4 will require the binding of additional ligands (in addition to the four nitrogen atoms of the macrocycle), which can be provided by functionalizing the macrocycle with additional pendant coordination groups.

THE LIGANDS OF SCHIFF BASE

Schiff bases containing polydentate group 45 have not only produced stable metal compounds, but these ligands and their metal bonds also play a role. Some examples of such types of Schiff basen ligands are shown below47 (as in Fig. 1.10).

PREPARATION AND MECHANISM OF SCHIFF BASE LIGANDS 48

The Mannich reaction is also considered a Mannich reaction, used for the activation of a proton to form the intermediate CH acidic compounds. Because the reaction takes place under acidic conditions, the compound forms a carbonyl functional group (in this case, an enol), after which it can attack the iminium ion.

UNSYMMETRICAL SCHIFF BASE LIGAND

THE MACROCYCLIC LIGANDS AND THEIR BEHAVIOUR

Broad classification of macrocyclic ligands: 53

Planar with unsaturated rings, as in porphyrin and its derivatives, the metal atom may be out of the ligand plane of the donor N atom (as in Fig. 1.13).

Macrocyclic complexes have the following characteristics. 54

TEMPLATE SYNTHESIS OF MACROCYCLIC COMPLEXES The rich chemistry of the complexes of macrocyclic ligands continues to be

It should be noted that there must be some control of the reaction by the size of the metal used.

MACROCYCLIC COMPOUNDS CONTAINING “OXO”

COORDINATION COMPLEX OF PERCHLORATE ION

The above complex coordinates the perchlorate to the metal, as a result of the proposed IR band at cm-1. Based on IR spectra a band at cm-1 regions showed this is assignable that perchlorate coordinate to the metal.83,84.

BIOLOGICAL ACTIVITY OF SOME IMPORTANT COMPOUNDS

Cancer is a disease characterized by uncontrolled multiplication and spread within the organism of apparently abnormal forms of the organism's own cell. From the above discussion, it can be seen that the medicinal activity of metal complexes significantly affects the bioavailability of the drug in our body and provides various possibilities for the biological functioning of all living systems.

AIM OF THE PRESENT WORK

Weighing
Melting Point Measurement
Infrared spectra
Conductivity
Magnetic moments
Metal estimation
Elemental analysis

The zero magnetic sensitivity knob is turned until the numeric display shows zero (000) and the calibration sample [HgCo(SCN)4. The molar sensitivity Xm is the equivalent mass sensitivity Xg multiplied by the formula weight of the substance.

Table 2.1: Unpaired spins and magnetic moments No. of Unpaired

PURIFICATION OF THE SOLVENTS 102

Ethanol

The process of adding acids and drying was continued until there was no black material. Distilled water (100 ml) was added to dissolve the residue and then the metal was estimated complexometrically92.

Acetone

NAME OF THE CHEMICALS/REAGENTS USED AND SUPPLIERS

PREPARATION OF COMPLEXES

Preparation of malonodihydrazide 105 C 3 H 8 N 4 O 2
Preparation of Metal Perchlorate
PREPARATION OF MACROCYCLIC COMPLEXES OF Ni(II)

Preparation of [Ni(C 8 H 16 N 8 O 4 )(ClO 4 ) 2 ] complex 1

PREPARATION OF MACROCYCLIC COMPLEXES OF Cu(II)

Preparation of [Cu(C 8 H 16 N 8 O 4 )(ClO 4 ) 2 ] Complex 4
Preparation of [Cu(C 10 H 20 N 8 O 4 )(ClO 4 ) 2 ] complex 5
Preparation of [Cu(C 24 H 28 N 8 O 4 )(ClO 4 ) 2 ] complex 6

PREPARATION OF MACROCYCLIC COMPLEXES OF Fe(II)

Preparation of [Fe(C 8 H 16 N 8 O 4 )(ClO 4 ) 2 ] complex 7

To the above solution was added nickel(II) perchlorate hexahydrate (1.096 g, 3 mmol in 10 ml water) and the entire mixture was refluxed and cooled for two hours with continuous stirring. To the above mixture containing nickel(II) perchlorate hexahydrate (0.731 g, 2 mmol in 10 ml water) was added and the entire mixture was refluxed and cooled for 12 hours with continuous stirring. To the above mixture was added copper(II) perchlorate hexahydrate (1.112 g, 3 mmol in 10 ml water) and the entire mixture was refluxed and cooled for 4 hours with continuous stirring.

To the above mixture was added copper(II) perchlorate hexahydrate (0.7410 g, 2 mmol in 10 mL water) and the entire mixture was refluxed for 4 hours with continuous stirring and cooled to room temperature. To the above solution was added iron(II) perchlorate hexahydrate (1.077 g, 3 mmol in 10 ml water) and the entire mixture was refluxed and cooled for two hours with continuous stirring. To the above solution was added iron(II) perchlorate hexahydrate (0.718 g, 2 mmol in 10 ml water) and the entire mixture was refluxed and cooled for two hours with continuous stirring.

To the above mixture was added iron(II) perchlorate hexahydrate (0.718 g, 2 mmol in 10 mL water) and the entire mixture was refluxed with continuous stirring for 4 hours and cooled to room temperature.

MACROCYCLIC COMPLEXES OF Ni (II)

This stretching frequency is suggested to be the coordination of perchlorate to the metal through the O atom65,66,73. A medium band at cm-1 region is tentatively attributed to the ν(M-N) mode102,103 indicating the coordination of the lignad to the metal through the nitrogen atom. These values correspond to two unpaired electrons of Ni(II) d8 system indicate the octahedral environment of the complexes which is consistent with the literature value1.

The elemental analyzes (C, H and N) (Table 4.1) and metal estimation data (Table 4.3) of the complexes are consistent with the proposed formula. On the basis of elemental analysis magnetic moment and conductance measurements, UV Visible spectra, infrared spectra and other physical properties, the proposed structure of the complexes is octahedral in nature as in Fig.4.7.

MACROCYCLIC COMPLEXES OF Cu(II)

These stretching frequencies are suggested to be the coordination of the perchlorate moiety to the metal through the O atom65,66,73. An intermediate band at the (407-412) cm-1 region is tentatively attributed to the ν(M-N) mode102,103, indicating the coordination of the ligand to the metal through the nitrogen atom. These values correspond to an unpaired electron of the Cu(II) d9 system, suggesting that the octahedral environment of the complexes is consistent with the literature value1.

The elemental analyzes (C, H and N) (Table 4.6) and metal estimation data (Table 4.8) of the complexes are consistent with the proposed formula. Based on elemental analysis, magnetic moment and conductivity measurements, UV-visible spectra, infrared spectra, and other physical properties, the structure of the complexes is octahedral in nature, as shown in Figure 4.14.

MACROCYCLIC COMPLEXES OF Fe(II)

These values correspond to four unpaired electrons of Fe(II) d6 system, representing the octahedral environment of the complexes which is consistent with the literature value1. The elemental analyzes (C, H and N) (Table 4.11) and metal estimation data (Table 4.13) of the complexes agree with the proposed formula. Based on elemental analysis, magnetic moment and conductance measurements, UV Visible spectra, infrared spectra and other physical properties, the structure of the complex octahedral is as in Fig.4.22.

Natarajan, Synthesis, characterization and biological activities of ruthenium(II)carbonyl complexes containing bifunctional tridentate Schiff bases; Jayabalakrishnan, responds. Badwaik, Hydrazone as a complex former: synthesis, structural characterization and biological studies of some complexes; Russ. Suryawanshi, Synthesis structural investigation and biological studies of some transition metal chelates of acid hydrazone; Polish J.

Yufit, copper(II) complexes of the isomeric tetraazamacrocyclic ligands 1,11- and 1,8-bis(2-pyridylmethyltetraazacyclotetradecane and of the 1,4,8,11-tetraazacyclotetradecane-5,12-dione analogue in neutral and basic form pH, J.

INTRODUCTION AND PRINCIPLE

After an initial lag phase, a logarithmic growth phase begins at which point bacterial multiplication begins to proceed faster than the drug can diffuse and the bacterial cell that is not inhibited by the antimicrobial agents will continue to multiply until a lawn of grown can be visualized. Antimicrobial activities of the test sample are expressed by measuring the zone of inhibition observed around the area of the disk. The diameter of the inhibition is usually measured to understand the extent of inhibition at different concentrations.

APPARATUS AND REAGENTS

METHOD

TEST OF ORGANISMS USED FOR THE STUDY

CULTURE MEDIA

PREPARATION OF FRESH CULTURE

Tryptone NaCl and yeast extract of calculated amount were taken in a conical flask and distilled water was added (volume should be less than 1 liter), the contents were heated in water bath to a clear solution. The conical flask was plugged with cotton and then autoclaved at 1 atm pressure for 15 minutes at 120°C.

PREPARATION OF THE CULTURE PLATE

The test microorganisms of pure culture were streaked onto the nutrient broth media using a sterile loop in an aseptic condition and incubated for 24 hours at 370C. The media was poured into a petri dish on a level horizontal surface to give a uniform depth of approximately 4 mm. After the media was completely solidified, 4-5 holes were made in it with the help of a brother.

Immediately before use, the agar cover plates were placed in an incubator (25 °C) for approximately 10-15 minutes until the surface moisture was lost by evaporation.

Preparation of discs

Standard Disc

PLACEMENT OF THE DISC AND INCUBATION

Determination of the zone of inhibition

RESULT OF THE ANTIBACTERIAL ACTIVITY OF THE COMPLEXES (1-9) AGAINIST THE FOURTEEN

Complex No Symbol Zone of inhibition of mycelial growth (in mm) 200 µg/slice 100 µg/slice 50 µg/slice 30 µg/slice.

Table 5.1: Antibacterial activity of the complexes 2, 3 against Salmonella-17.

DISCUSSION

Complex 3 showed the best activity against Salmonella-17, Shigella shiga, Shigella sonnei and less activity against Pseudomonas aeruginosa. Complex 5 showed the best activity against Bacillus cereus and less activity against Shigella boydii complex 2, 4, 6 did not show good activities against the above fourteen pathogenic bacteria. Good activity against Bacillus cereus and less activity against Shigella dysenteriae and other bacteria was not observed.

Similarly, complex 2 showed good activities against Shigella shiga and less activity against Bacillus megatrium and no activity was observed against other bacteria. Complex 4 showed good activity against Salmonella and less activity against Shigella sonnei and no activity was observed against other bacteria. Complex 6 showed good activity against Shigella dysenteriae and less activity against Shigella boydii, Bacillus megaterium, and no activity was observed against other bacteria.

From this it is concluded that the complex 1, 3 and 5 showed good activities against the fourteen pathogenic bacteria compared to the standard compound, kanamycin.

DETERMINATION OF MINIMUM INHIBITORY CONCENTRATIONS (MIC) OF COMPLEXES

Introduction
Principle of serial tube dilution technique
Preparation of the sample solution
Preparation of Inoculum
Procedure

2.048 mg of the test compound was taken in a vial 2 ml of methanol was added to the vial to dissolve the compound. Fresh culture of the test organisms was grown at 37.5°C overnight on nutrient agar medium. After cooling, 1 mL of the sample solution was added to the 1 C temperature and 1 atm. pressure.

The contents of the second tube were mixed well and again 1 mL of this mixture was transferred to 3. 10 µL of appropriately diluted inocula was added to each of the nine tubes and mixed well. 10 µL of the inoculum was added to the control tube Ci to observe the growth of the organism in the medium used.

1 mL of the sample solution was added mixed well and 1 mL of this mixed content was discarded that is to check the clarity of the medium in the presence of diluted.

RESULT OF THE MINIMUM INHIBITORY CONCENTRATION OF THE COMPLEXES

DISCUSSION