161959-13-3Relevant articles and documents
Synthesis, characterization, catalytic and antiamoebic activity of vanadium complexes of binucleating bis(dibasic tridentate ONS donor) ligand systems
Maurya, Mannar R.,Haldar, Chanchal,Khan, Aftab Alam,Azam, Amir,Salahuddin, Attar,Kumar, Amit,Costa Pessoa, Joao
, p. 2560 - 2577 (2012)
[VIVO(acac)2] (acac = acetylacetonate) was treated with ligands CH2(H2L)2 in methanol heated at reflux to yield two neutral binuclear VIV complexes with the formula [CH2{VIVOL(H2O)}2], namely, 1 and 2. Ligands CH2(H2L)2 I and II were derived from 5,5'-methylenebis(salicylaldehyde) and S-benzyldithiocarbazate [CH 2(H2sal-sbdt)2, I] or S-methyldithiocarbazate [CH2(H2sal-smdt)2, II]. Aerial oxidation of 1 and 2 in the presence of KOH or CsOH·H2O resulted in the formation of dioxidovanadium(V) complexes, K2[CH2{V VO2(sal-sbdt)}2]·2H2O (3), Cs2[CH2{VVO2(sal-sbdt)} 2]·2H2O (4), K2[CH2{V VO2(sal-smdt)}2]·2H2O (5) and Cs2[CH2{VVO2(sal-smdt)} 2]·2H2O (6). The compounds were characterized in the solid state and in solution, namely, by spectroscopic techniques (IR, UV/Vis, EPR, 1H, 13C and 51V NMR spectroscopy). It is demonstrated that the VVO2 complexes 3-6 are efficient and selective towards the oxidative bromination by H2O 2 of styrene to yield 1,2-dibromo-1-phenylethane, 1-phenylethane-1,2-diol and 2-bromo-1-phenylethane-1-ol, and of salicylaldehyde to yield 5-bromosalicylaldehyde, 3,5-dibromosalicylaldehyde and 2,4,6-tribromophenol; they therefore act as functional models of vanadium-dependent haloperoxidases. It is also shown that Cs2[CH 2{VVO2(sal-sbdt)}2]·2H 2O (4) and Cs2[CH2{VVO 2(sal-smdt)}2]·2H2O (6) are catalyst precursors for the catalytic oxidation of styrene by peroxide to yield styrene oxide, benzaldehyde, 1-phenylethane-1,2-diol, benzoic acid and phenylacetaldehyde. Plausible intermediates involved in these catalytic processes were established by UV/Vis, EPR and 51V NMR spectroscopic studies. The VVO2 complexes along with ligands I and II were also screened against HM1:1MSS strains of Entamoeba histolytica; the IC50 values of compounds 3, 4 and 5 were significantly lower than that of metronidazole, thereby suggesting that they may be promising drugs for the treatment of amoebiasis. Copyright
Binuclear Dioxomolybdenum(VI) Complexes of Flexibly-Bridged Hexadentate Tetraanionic Schiff's Bases Derived from Methylene- or Dithio-bis(salicylaldehyde) and S-Methyldithiocarbazate or S-Benzyldithiocarbazate
Maurya, Mannar R.,Antony, Deena C.,Gopinathan, Sarada,Gopinathan, Changaramponnath
, p. 554 - 558 (2007/10/02)
The flexibly-bridged hexadentate tetraanionic ligands, LH4 , react with in a 1:2 molar ratio in refluxing methanol to give complexes of the type .These complexes show an intense ν(Mo=O) band at 924-948 cm-1 and a broad but strong band at ca. 850 cm-1 due to weakened ν(Mo=O) as a result of MoO->Mo interactions.An oligomeric structure, in which each Mo(VI) ion achieves a pseudo-octahedral structure via MoO->Mo bridging, has been suggested for these complexes. reacts with monodentate ligands (D) like pyridine, 4-methylpyridine, and dimethylsulfoxide and forms six-coordinated complexes of the type which are monomers.Cyclic voltammetry measurements indicate that these MoVIO2 complexes are resistant to MoIVO reduction.
