Isonicotinic acid hydrazide (1mmol) and 2-acetylnaphthalene (1mmol) were refluxed together for 3 hours in the presence of a drop of concentyrated HCl. The volume of the mixture was reduced to half. It was then cooled in a refrigerator when light yellow crystals separated .It was filtered, washed several times with cold ethanol and dried.

The ligand(16) gave the following data IR (KBr)

v_max = 1612cm-1

= 1664cm-1

= 761cm-1

The complex was prepared by carrying out the insitu reaction of amine (INH) 2- acetyl naphthalene and the metal salt cupper chloride. Isonicotinic acid hydrazide (1mmol) and 2 acetylnapthalene (1mmol) were taken together in ethanol (30ml) and refluxed for an hour after which copper chloride (1mmol) in ethanol was added and reflux continued for another 3hours. Upon cooling microcrystalline copper complexes precipitated .It was filtered washed thoroughly with ethanol and dried .The yield was quantitative.

The complex gave the following IR spectral data

v_max =1600cm-1

=1733cm-1

= 761cm-1

IR spectra were recorded in KBr medium on a Perkin–Elmer 783 spectrophotometer. UV-Vis spectra of complex was recorded in DMSO on a Shimadzu UV-1601 spectrophotometer.The magnetic property of the metal complex was studied by Magnetometer .

Antibacterial assay

The sterilized Sabouraud’s dextrose agar medium (Dextrose 4.0 g, Mycological peptone1.0 g,Agar 2.0 g, pH 5.0,Distilled water 100 ml,) was poured to a Petri dish in a uniform thickness and kept aside for solidification. Using sterilized swabs, even distribution of lawn culture was prepared using desired fungi such as A.niger , Pen.notatum, C.albicans, C.tropicalis, in SDA plates. The inoculated plates were kept aside for few minutes. Using well cutter 2 wells are made in those plates at required distance. In each step of well cutting, the well cutter was thoroughly wiped with alcohol using sterilized micropipette, 20l of different solvents with compound was added in to one well and in another well the same volume of corresponding controls (solvent without compound) were added. After diffusion, the plates were incubated at room temperature for 24- 48 hours. After incubation, the inhibition of growth was analyzed and results were recorded.

One ml of extract (1mg/ml) was incorporated into one ml of nutrient broth and Sabouraud’s dextrose broth and serially diluted to obtain concentration of 1000µg/ml, 500µg/ml, 125µg/ml, 62.5µg/ml, 31.25µg/ml respectively. 20l of the bacterial , fumgal inoculum was added to each of the test tubes. The tube without the extract served as control. The tubes were incubated at room temperature and readings were recorded after a period of 24 hrs for bacteria and 3 days for fungi.MIC was recorded as the lowest concentration of the extract at which no visible growth of the bacterial and fungal occurred after a period of seven days incubation.

Reaction of Salicylaldehyde with 2-acetyl naphthalene in ethanol showed a new spot after refluxing for four hours. After usual workup a yellow solid showed the following special features.

The ligands are expected to be bidentate, the possible coordination sites being the azomethine-nitrogen and the amide group. The NH stretching absorbtion (34) in the free ligands occurs at 3330 cm-1. The ligand band due to c=o appears at 1664 cm-1. The band due to c = N mode appears at 1612 cm-1.

Reaction of the ligand and Cu(III) in ethanol gave yellowish green solid. The IR and magnetic susceptibility measurement of the complex showed the following spectral features.

IR: The band due to C= N mode undergo a shift to lower frequency and is observed as a strong peak in the region 1600 cm-1, suggesting participation of exocyclic azomethine nitrogen in the complex formation.

The room temperature magnetic moment of Cu(III) chelates is found to be 2.70BM indicating paramagnetic, low spin d9 complex with ground state term 2D. The magnetic moment value can be calculated as follows (Table 1).

Figure 1

Where, MW = Molecular weight of the complex

SW = Weight of the substance

Figure 2

Table.1 Vibrating Sample Magnetometer Data of Cu (III) complex

The IR and magnetic susceptibility studies of the complex indicates that it is an octahedral complex of the type CuL₃ and the structure of the complex is assigned in Fig 1.

Figure 3

Fig.2.Structure of Cu (III) shiff base complex

The Cu(III) metal complexes were effective against all the test organisms, both in Ethanol and methanol extract form. The methanol extract was more active against the test organisms than the ethanol extract. The antimicrobial activity of ethanol extract of selected complexes in well method was performed and was found to be effective. (Table, 2)

Figure 4

Table.2 Antimicrobial activity of methanol extract of Cu (III) complex (Zone of inhibition in mm)

The minimal inhibitory concentration of Ethanol extract of Cu(III) against Staphylococcus aureus was 500 µg/ml, for Salmonella typhi was 1000µg/ml, for Escherichia coli 1000µg/ml Pseudomonas aeruginosa was 1000 µg/ml, Shigella dysenteriae was 500µg/ml, for Aspergillus niger 1000 µg/ml Penicillium notatum was 1000µg/ml for Candida albicans was 500µg/ml, and for Candida tropicalis was 500µg/ml.(Table, 3)

Figure 5

Table.3 Minimum inhibitory concentration of ethanol extract of Cu(III) on selected bacteria and fungi

Various studies (5) have shown a relationship between the metal ions and their metal complexes as antitumour (6) and antibacterial agents, which is a subject of great interest. The inorganic pharmacology started to be an important field with more than 25 inorganic compounds being used in therapy as antibacterial, antiviral and anticancer drugs (7). It was seen that the biological active compounds become more bacteriostatic and carcinostatic upon chelation with metal ions. Schiff bases have also attracted considerable attention in terms with their chelating abilities and analytical applications (8,9).

Thus the present study showed the significant antimicrobial activity to Staphylococcus aureus and Candida albicans. The further study is need for the identification of active site is essential because the predication of lead molecule and drug like property at the onset of drug design will helps in drug development.