• Baliram Singh
• Rabindra Singh

Some novel complexes of Ni(II) with ligands 3-hydroxyindole-2-carbaldehyde semicarbazone (L1H) and 5-hydroxyimidazole-2-carbaldehyde semicarbazone (L2H) have been synthesised in acidic (pH=2.0), neutral (pH=7.0) and alkaline (pH=10.0) media in order to investigate the pH dependent coordination behaviour of the selected ligands. The synthesised complexes have been characterised on the basis of elemental analyses, determination of molar masses, molar conductance and magnetic susceptibility measurements, UV and IR spectral studies. In acidic (pH=2.0) and neutral (pH=7.0) media, both L1H and L2H behave as neutral tridentate ligands while in alkaline medium (pH=10.0), they behave as monoanionic tridentate ligands. The complexes are found to be monomeric as indicated by their observed molar masses and have molecular formula [Ni(L1H)2]Cl2 and [Ni(L2H)2]Cl2 in both acidic and neutral media. However, they have been formulated as [Ni(L1)2] and [Ni(L2)2] in alkaline medium. The complexes synthesised in acidic and neutral media have 1 : 2 electrolytic nature whereas those syntehsised in alkaline medium are non-electrolytes as indicated by their molar conductance values. Octahedral geometry has been suggested for all the complexes on the basis of magnetic moment values as well as the number and positions of electronic spectral bands. The nature of metal-ligand bonding has been established by infrared spectral studies.

Schiff base, semicarbazones, indole, imidazole, tridentate ligands.

"Synthesis and Characterisation of Some Novel Ni(II) Complexes of Semicarbazones derived from Heterocyclic Aldehydes ", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.6, Issue 4, page no.168-176, April-2019, Available :http://www.jetir.org/papers/JETIR1904W24.pdf

"Synthesis and Characterisation of Some Novel Ni(II) Complexes of Semicarbazones derived from Heterocyclic Aldehydes ", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.6, Issue 4, page no. pp168-176, April-2019, Available at : http://www.jetir.org/papers/JETIR1904W24.pdf