Prathapachandra Kurup, M R; Laly, K; Suja, Krishnan(Elsevier, November 10, 2009)
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Abstract:
Five Mn(II) complexes of bis(thiosemicarbazones) which are represented as [Mn(H2Ac4Ph)Cl2]
(1), [Mn(Ac4Ph)H2O] (2), [Mn(H2Ac4Cy)Cl2]·H2O (3), [Mn(H2Ac4Et)Cl2]·3H2O (4) and
[Mn(H2Ac4Et)(OAc)2]·3H2O (5) have been synthesized and characterized by elemental analyses,
electronic, infrared and EPR spectral techniques. In all the complexes except [Mn(Ac4Ph)H2O], the
ligands act as pentadentate neutral molecules and coordinate to Mn(II) ion through two thione sulfur
atoms, two azomethine nitrogens and the pyridine nitrogen, suggesting a heptacoordination. While in
compound [Mn(Ac4Ph)H2O], the dianionic ligand is coordinated to the metal suggesting six coordination
in this case. Magnetic studies indicate the high spin state of Mn(II). Conductivity measurements reveal
their non-electrolyte nature. EPR studies indicate five g values for [Mn(Ac4Ph)H2O] showing zero field
splitting.
Prathapachandra Kurup, M R; Neema, Ani Mangalam(Elsevier, July 27, 2008)
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Abstract:
Four oxovanadium and one dioxovanadium complex with 2-hydroxyacetophenone N(4)-
phenylthiosemicarbazone (H2L) which are represented as [VOLphen]·2H2O (1), [VOLbipy] (2),
[VOLdmbipy] (3), [VOL]2 (4) and [VO2HL]·CH3OH (5) have been synthesized and characterized by
elemental analyses, electronic, infrared and EPR spectral techniques. In all the complexes 1–4 the
ligand coordinates through phenolic oxygen, azomethine nitrogen and thiolate sulfur. But in complex
[VO2HL]·CH3OH, coordination takes place in thione form instead of thiolate sulfur. All the complexes
except [VO2HL]·CH3OH are EPR active due to the presence of an unpaired electron. In frozen DMF at 77 K,
all the oxovanadium(IV) complexes show axial anisotropy with two sets of eight line patterns
Prathapachandra Kurup, M R; Suma, S; Sudarsana Kumar, M R; Siji, V L(Elsevier, February 26, 2010)
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Abstract:
Eight new transition metal complexes of benzaldehyde-N(4)–phenylsemicarbazone have been synthesized
and characterized by elemental analyses, molar conductance, electronic and infrared spectral
studies. In all the complexes, the semicarbazone is coordinated as neutral bidentate ligand. 1H NMR
spectrum of [Zn(HL)2(OAc)2] shows that there is no enolisation of the ligand in the complex. The magnetic
susceptibility measurements indicate that Cr(III), Mn(II), Fe(III), Co(II) and Cu(II) complexes are
paramagnetic and Ni(II) is diamagnetic. The EPR spectrum of [Mn(HL)2(OAc)2] in DMF solution at 77K
shows hyperfine sextet with low intensity forbidden lines lying between each of the two main hyperfine
lines. The g values calculated for the [Cu(HL)2SO4] complex in frozen DMF, indicate the presence of
unpaired electron in the dx2−y2 orbital. The metal ligand bonding parameters evaluated showed strong
in-plane bonding and in-plane bonding. The ligand and complexes were screened for their possible
antimicrobial activities.
Description:
Spectrochimica Acta Part A 76 (2010) 22–28 doi:10.1016/j.saa.2010.02.035