Stability constant study of transition metal complexes with pharmacologically active ligand(N-[-(4-chlorophenyl)methylene] nicotinohydrazide) by pH metric Technique

Abstract

Pharmacologically active organic ligands (N-[-(4-chlorophenyl)methylene] nicotinohydrazide) synthesized through the condensation of equimolar mixture of Antimycobacterial agent(nicotinohydrazide)with aromatic aldehyde. The reaction progress and purity of organic ligands were verifying by thin layer chromatography. Formation of organic ligands was confirming with the help of MP, IR, 1 H NMR, 13 C NMR and elemental analysis.Further formation of complexes of transition elements like Mn(II), CO(II), Ni(II), Cu(II) and Zn(II) with organic ligand (Schiff base) N-[-(4-chlorophenyl)methylene] nicotinohydrazide, were studying by the pH-metric technique at 27±1 0 C in 70%(v/v) ethanol water medium at 1M (NaClO4) ionic strength. The stability constants of these binary complexes were evaluating and order of stability constant found as Zn (II) > Cu (II) >Ni (II) >Mn(II) > Co (II). Key word : Binary complexation,N-[-(4-chlorophenyl)methylene]nicotinohydrazide, transition metals, pH metric technique. Introduction In the field of coordination chemistry, metal ions perform vital roles in biological processes. The mineral complexes have been studied with the basic Schiff links to be utilized in the biological, clinical, analytical and pharmacological fields 1 .Schiff bases perform an important function in coordination chemistry because they easily form stable complexes with most transitional metal ions 2 .Schiff bases have a broad assortment of applications in different regions such as biological chemistry, organic and inorganic chemistry 3 .Schiff bases are now attracting the attention of medicinal chemist. Schiff base containing an amine group (–RC=N–) are commonly formed by the intensification of an initial amine with an active carbonyl 4 . Schiff bases and their complexes have a variety of applications in biological clinical and analytical fields 5 .The complexation of Schiff base with transition metals increasethebiologicalactivity 6 . Isoniazid is antimycobacterial drug and used. Zamzam Taher Omar (Al-Ahdal) et al /International Journal of ChemTech Research, 2018,11(11): 211-216 DOI= http://dx.doi.org/10.20902/IJCTR.2018.111121 International Journal of ChemTech Research CODEN (USA): IJCRGG, ISSN: 0974-4290, ISSN(Online):2455-9555 Vol.11 No.11, pp 211-216, 2018 Zamzam Taher Omar (Al-Ahdal) et al /International Journal of ChemTech Research, 2018,11(11): 211-216. 212 also primarily as a tuberculostatic 7 .Itbecomes a starting point in the search for new vital derivatives and analogues such as hydrazones which have been informed as active anti-tuberculosis drugs 8 .For the investigation of stability constant various techniques are utilizing such as potentiometry etc. pH-metric study is one of the best widely used technique because it has several superiority such as, it is easy to understand and work, cheap technique etc.A pH meter is using to find the stability constant which is useful for the formation of a complex in solution 9-16 .The stability of metal complexes with medicinal drugs perform greater role in the biological and chemical activity 17 . Due to these valuable findings observed in literature review, present work was planning and well executed for the preparation of organic ligands through the condensation of 4-chlorobenzaldehyde with isoniazid. Complexation of newly synthesized organic ligand was carrying out with transition metals to determine the order of stability constants by using pH-metric technique. Material and Methods: