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The tridentate ONN donor ligand, Hbzpy-fah (I) (Hbzpy-fah = Schiff base derived from 2-benzoylpyridine and 2-furoylhydrazide) upon reaction with [VIVO(acac)2] in methanol followed by aerial oxidation give a dinuclear complex, [{VVO(bzpy-fah)}2(μ-O)2] (1) having [{VVO}2(μ-O)2]2+ core. Treatment of 1 with H2O2 in methanol results in the formation of dinuclear peroxido complex, [{VVO(bzpy-fah)}2(μ-O2)2] (2). The molecular structure of 2 was determined by single-crystal X-ray diffraction, confirming the ONN binding mode of I and μ-bis(peroxido) with side-on coordination. Reaction of 1 with imidazolomethylpolystyrene cross-linked with 5% divinylbenzene (PS-im) in DMF gives the polymer-supported complex 3 (abbreviated as PS-im[VVO2(bzpy-fah)]) which was characterized by field-emission scanning electron micrographs (FE-SEM) as well as energy dispersive X-ray (EDAX), atomic force microscopy (AFM) and thermal analysis along with usual spectroscopic techniques. Complexes 1 and 3 have been used as catalyst precursors for the oxidation of isoeugenol in the presence of aqueous H2O2 as oxidant and gave vanillin, vanillic acid and dehydrodiisoeugenol. The polymer-supported complex showed higher conversion than its neat counterpart. This has also allowed for recyclable catalytic system with increased catalyst lifetime and thus proved to be better over the homogeneous counterpart.

Two promising palladium(II) compounds of general formula, cis-[Pd(L-O,S)2] [where HL-O,S = N-(di(butyl/phenyl)carbamothioyl)benzamide] as metal based antiamoebic drug candidates, have been synthesized. Both complexes are characterized in the solid state by FT-IR spectroscopy, TGA and single crystal X-ray study, as well as in solution by other spectroscopic techniques such as (1)H and (13)C NMR, and UV-visible. All these studies confirm the coordination of ligands through oxygen and sulphur atoms upon thioenolization induced delocalization. Complexes adopt cis-configuration in the solid state. Both the complexes and their respective ligands were screened in vitro for antiamoebic activity against HM1:1MSS strain of Entamoeba histolytica by microdilution method and cell viability in response to drugs was checked by using MTT assay. The IC50 values in the range 0.30-0.80 μM for ligands as well as complexes compared to 1.40 for metronidazole along with their similar inhibitory effect on cell viability of HEK293 cells like metronidazole make them promising future antiamoebic drugs.