Synthesis and Antimicrobial Activities of Zn (II) Complex of 2,5-Diamino-1,3,4-Thiadiazole

Aim:

The ligands contain O, N, S-Sequence and their metal complexes have their various chemical and structural characteristics and their wide application in the field of pharmacology. The extreme efforts have been made to design novel drug to strains of resistant micro-organisms. This has required the need to search for more efficient drugs.

The Zn (II) metal complexes with a tridentate ligand 2,5-diamino-1,3,4-thiadiazole has been prepared by cyclisation of bithiourea in a 3% hydrogen peroxide medium. 2,5-diamino-1,3, 4-thiadiazole acts as neutral tridentate ligand and coordinates through the sulphur atom and nitrogen of the amines. The complexes are non-electrolyte in DMF. The complexes exhibited octahedral geometry. The antimicrobial activities of ligand and its complexes were screened using sensitivity test, minimum inhibition concentration and minimum bacterial concentration method. Metal chelates showed greater antimicrobial activities as compared to the control and the ligand. The metal chelates and the ligand did not exhibited activity against Aspergillus niger and Penicillin species.

Methods:

Elemental analyses, IR spectra, magnetic susceptibilities by using Faraday Balance, molar conductance by using Genway 4200 conductivity meter. Metal estimation by using Alpha 4 Atomic Absorption Spectrophotometer. Thin layer chromatography was carried out using TLC plate coated with silica gel.

Results:

The results of the elemental analyses are in good agreement with those calculated for the suggested formulae, 1:2 (M: L) solid chelates are isolated and found to have the general formulae [(ML₂)] X₂; M=Zn (II) (X=Cl).

The IR spectra revealed that the ligand L is a neutral tridentate ligand. It coordinated to the metal ions via the nitrogen of the amines and sulphur atom. The molar conductance value of the Zn (II) complex was low which indicate the nonelectrolytic nature of the complex. The ligand and metal complexes show antimicrobial effect against the tested organism species except against molds of penicillin and Aspergillius. Niesseria gonorrhoea was probably the most sensitive organism to the 2,5-Diamino-1,3,4-Thiadizole and its metal complexes. Metal complexes showed greater activity against some of the micro-organisms compared to the parent compounds

Conclusion:

In this paper we conclude from combined results of the chemical and physical analysis that the ligand (2,5-diamino-1,3,4-thiadiazole) coordinated with Zn. The metal complexes possess better physical properties than the parent compound. Metal complex of 2,5-diamino-1,3,4-thiadiazole would be a better therapeutic drug for antibacterial treatment.