β-diketone and its five transition metal complexes with stoichiometry [M(L)2(H2O)2] [M= Mn (1), Fe (2), Co (3), Ni (4) and Cu (5); [L= 3-hydroxy-3-(2-hydroxyphenyl)-1-(2-iodo-5-methyl phenyl)prop-2-en-1-one] has been prepared. Ligand (L) was obtained by the well-known Baker-Venkataraman transformation. β-diketones exist in the intramolecular hydrogen bonded keto-enol tautomerism hence form a metal chelate, as an enolic hydrogen atom can be replaced by metal and ketonic oxygen, thereby completing the chelate ring, hence act as a chelating in the preparation of metal complexes. The synthesized compound has been characterized by NMR, IR, LC-MS and elemental analysis. Solution conductivity and electrochemical behavior were also studied by cyclic voltammetry. The synthesized compounds were screened in vitro for their antibacterial, antioxidant and anti-inflammatory activities, it is observed that complexation led to a remarkable increase in activities.

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It is well known that β-diketones are also formed through Baker-Venkataraman transformation. In the present case, 3-bromo-2-methylbenzoic acid reacts with ortho-hydroxyacetophenone at room temperature to yield ester. Ester on further Baker-Venkataraman transformation yields 1,3-diketone (L) i.e. 1-(3-bromo-2-methylphenyl)-3-hydroxy-3-(2-hydroxyphenyl)prop-2-en-1-one. Five complexes of Mn(II), Fe(III), Co(II), Ni(II) and Cu(II) with bidentate ligand (L), have been synthesized from reaction of the ligand (L) with respective metal nitrates. β-diketone exhibits keto-enol tautomerism, their keto-enol tautomerism was studied in solution by IR and NMR spectroscopy. Due to enolization β-diketone acts as ligand and hence used to synthesized Mn(II), Fe(III), Co(II), NI(II) and Cu(II) complexes. The synthesized ligand has been characterized by elemental analysis, 1 H, 13 C NMR, LC-MS and FT-IR. The magnetic susceptibility and solution conductivity were also studied. The synthesized complexes were also studied antimicrobial screening.