Synthesis, Determination of Structure and Biological Activity of Metal Complex (Drug)

Dr.M. M. Awatade (mmawatade@coe.sveri.ac.in) Assistant Professor, SVERI’s College of Engineering, Pandharpur

Introduction

Due to coordination chemistry the area of inorganic chemistry, most widely developed in last few decades. Beauty of Coordination chemistry lies in the fact that minute changes in a metal ion environment induce the change in properties of compounds. Studies on transition metal complexes have achieved great interest due to their important applications in medicine, biology, catalysis, photonics, molecular magnetism, supramolecular chemistry, non-silicon-based devices, precursors and photonic devices sensors. The studies on coordination complexes have become a challenge to the present day chemist.

            The present work describes the synthesis, Characterization and Biological activity of compound.

Keywords: Transition metal complexes, Schiff base, antibacterial activity.

Synthesis   

1 Synthesis of Schiff   Base:-   Schiff base was prepared by refluxing equimolar proportion of salicylaldehyde and substitute benzhydrazide in alcohol medium for about  

1 Synthesis of Schiff   Base:-   Schiff base was prepared by refluxing equimolar proportion of salicylaldehyde and substitute benzhydrazide in alcohol medium for about

an hour on water bath. The solids separated on cooling were filtered and recrystallized from alcohol. All Schiff bases were dried.

2 Synthesis of metal complex: – A hot solution of Schiff base (1mmol) in pure ethanol (20ml) was added to hot solution of Copper salt (1mmol) in minimum amount of ethanol and resulting dark colored solution was refluxed for 2-3 hours. The boiling solution was then allowed to cool at room temperature and stand overnight. Dark coloured crystalline solids were separated from the solution and filtered off, washed with ethanol and diethyl ether then dried.

Structure determination: – Structure of complex is determined by following method. The complex is green in color, soluble in DMF, DMSO. Result of elemental analysis shown in table No-1. It  show that the complex  have 1:1 stoichiometry.

Table No-1

Ligand / Complex	Empirical Formula	Colour	Melting point  (OC)	% Metal Found (Cal.)	% Carbon Found (Cal.)	% Hydrogen Found (Cal)	% Nitrogen Found (Cal.)
Sa-4-ClBH	C14H11N2O2Cl	Light yellow	158		61.15 (61.22)	4.10 (4.01)	10.15 (10)
Cu [SA4- Cl BH]	Cu(C14H11N2O2Cl)	Light  Green	248	18.83 (18.75)	49.84 (49.84)	3.26 (3.25)	8.3 (8.3)

1.  Conductance

         The molar conductance in DMSO at the concentration ~ 10^-3M is too small to measure. Hence the complex is   non-electrolytes.

2.   Magnetic property

               The magnetic moments measured at room temperature are listed in table.2 it is 1.79 B.M. suggest square planar structure.¹

3.  Electronic Spectra

                    Bivalent Cu (II) ion has electronic configuration 3d⁹. The square planar complex characterized by a broad band in the relatively high frequency region 675-725 nm. The band in the region 385 -410 nm represents cu-cu linkage. Hence dimeric square  planar structure in which two copper entities are linked through oxygen² .

Table No-2

Ligand / Complex	Molecular weight (Calculated)	µ eff  (298OK ) B.M.	Electronic spectra λmax(nm)
SA 4- Cl BH	274.61(274)	—	235,290,340.
[Cu( SA 4- Cl BH)]	337(337.34)	1.79	700,385.

4. Thermo gravimetric analysis

        Thermal   decomposition   of complexes has been studied as function of temperature ranging from 25⁰C to 800⁰C by heating in nitrogen atmosphere. Result of thermal analysis shown in Table-3 and fig-1

           In   Cu((II)  complex  weight  Losses  during  decomposition   from  25-390⁰C and   570-620 ⁰C  correspond  to  loss  of coordinated    benzhydrazide  and salicylaldehyde  respectively.³

           Final weight corresponds to that of metal oxide. Thermo gravimetric study indicates not only the presence of coordinating group in complex molecule but also describe in detail the decomposition pattern for the metal complex.  

6 Infrared Spectra

               The important infrared frequencies of the complex along with their assignments are listed in table-4.The infrared spectra of the Cu(II) complex  reproduced in fig. 2

Table-4

Complexes	ν (NH)	ν (C=N)	ν (C=C)	ν (C-O)
[ Cu(SA 4- Cl BH)]	—-	1612	1550, 1495	1350

 Fig-2

The band due to the phenolic C-O around 1280 cm^-1 shows a considerable high frequency shift ³⁹in the complexes and appear in the region 1350- 1305cm^-1.The C=N stretch of the ligand in the region1625-1610cm^-1 is observed in the 1612- 1600 cm^-1 region suggesting that the co-ordination bond is formed between the nitrogen of the azomethine group and the Cu(II) moiety. An intense band observed in the region 1640-1630 cm^-1 may be assigned to ύ (C=N) due to the enolic form of the ligand. ⁴     

All these observation together suggested `square planner structure of Cu (II) complex

Fig-3

Biological activity –Antibacterial activity of compound measure   by  the well diffusion method in DMSO solvent at a concentration of 0.5% and 1.0% Shown in fig-4  were checked against Gram- positive bacteria B. subtilis and Gram negative bacteria E. coil.  Diameters of the zones of inhibition (in millimeters) of standard drug ampicillin against B. subtilis and E. coil were found to be 30 and 26 respectively.

Fig-4        Fig-5

It is observed that metal complex is more bactericides than the ligand shown in fig-5. If the geometry and charge distribution around the compounds are incompatible with the geometry and the charge distrubution around the pores of the bacterial cell wall killing of bacteria takes place.               

Conclusion

• Structure of complex is square planner.
• Schiff base and their complex show more activity as compared to standard drug (Ampicillin).
• Complex is more active in killing the bacteria than their Schiff base.
• As the concentration of the complex increases tendency to kill bacteria   increases.

  Advantages – From result of biological activity it is cleared that this                                              

                            Complex can be used for design new of drug.

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