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Thermal and long period stability of series of V(V), V(IV) and V(III) complex with Schiff base ligands in solid state

Szklarzewicz Janusz, Jurowska Anna, Hodorowicz Maciej, Gryboś Ryszard

Science, Technology and Innovation

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2019

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Vol. 4, no. 1

30--36

EN

The synthesis and physicochemical properties of three new complexes of vanadium at +5, +4 and +3 oxidation state are described and discussed. The octahedral surrounding of vanadium for V(III) complexes of [V(L1)(HL1)] general formula is filled with two ONO tridentate ligand L, for V(IV) one ONO ligand L, oxido ligand and 1,10-phenanthroline (phen) as a co-ligand are presented in complexes of [VO(L2)(phen)]. For V(V) the complexes of [VO2(L1)(solv)] type were formed. As ligands, the H2L Schiff bases were formed in reaction between 5-hydroxysalcylaldehyde and phenylacetic hydrazide (H2L1) and 3,5- dichlorosalicyaldehyde and 4-hydroxybenzhydrazide (L2). The magnetic moment measurements, in 8 year period, show, that V(III) complexes slowly oxidise to V(IV) with preservation of the nonoxido character of the complexes, while V(IV) complexes were found to be stable. The TG and SDTA measurements indicate, that thermal stability depends mainly on the oxidation state of vanadium. The less thermally stable are the V(V) complexes, while V(IV) and V(III) are stable up to ca. 200oC. In solution, at pH 2 (similar to that in human digestion system), again the V(IV) are the most stable, only at pH 7.0 V(III) complexes had higher stability. The most stable, thus best for pharmaceutical use, are V(IV) complexes.

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Studies on Schiff Base Complexes of Salicylaldehyde with Sulphamethoxazole and Their Antimicrobial Activities

Sheela C., Gomathi A., Ravichandran S., Tharmaraj P.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 11

1781-1787

EN

New neutral Schiff base complexes of Cu(II), Co(II), Ni(II) and Zn(II) derived from salicylaldehyde and sulphamethoxazole have been synthesized. The structural features of the complexes have been confirmed by microanalytical data, IR, UV-Vis and EPR techniques. The electronic absorption spectra and magnetic susceptibility measurement values of the complexes indicate square-planar geometry for copper and nickel and tetrahedral for cobalt and zinc complexes. The neutral nature of the complexes follows from their low molar conductance values. The EPR spectrum of copper complex in DMSO at 300 K and 77 K was recorded and its salient features are reported. The antimicrobial activity of the complexes has been extensively studied on microorganisms such as Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa by well-diffusion technique using DMSO as a solvent. The values of zone of inhibition were found out at 37 graduateC for a period of 24 h. It has been found that all the studied complexes have higher activity than the free ligand and the standard.

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Synthesis and Characterization of Cu(ii), Co(II), Ni(II) and Zn(II) Schiff Base Complexes from 1-Amino-5-benzoyl-4-phenyl-1H-pyrimidine-2-one with Salicylaldehyde

Sönmez M., Çekerci M.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 7

907-914

EN

Cu(II), Co(II), Ni(II) and Zn(II) metal complexes of new heterocyclic Schiff base derived from 1-amino-5-benzoyl-4-phenyl-1H-pyrimidine-2-one with salicylaldehyde have been synthesized and characterized by elemental analyses, mass, electronic, IR and 1H NMR spectra, and also by molar conductivity measurements, magnetic moment measurements and thermogravimetric analyses (TGA). It has been found that the Schiff bases behave as a neutral bidentate (NO) and tridentate (ONO) ligands forming chelates with 1:2 (metal:ligand) stoichiometry. Octahedral environment is suggested for metal complexes. The conductivity data for the Ni(II) complexes are consistent with those expected for an electrolyte.

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Theoretical simulation of the infrared spectrum of salicylaldehyde

Boczar M., Wójcik M. J., Szczeponek K., Jamróz D., Ikeda S.

Bulletin of the Polish Academy of Sciences. Chemistry

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2002

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Vol. 50, No. 1

11-14

EN

Theoretical simulation of the v(s) stretching band is presented for salicylalde-hyde taking into account an adiabatic coupling between the high-frequency O-H stretching and the low-frequency intramolecular O...O stretching modes, linear and quadratic distortions of the potential energy for the low-frequency vibration in the excited state of the O-H stretching vibration and resonance interaction between the O-H and the C-H stretching vibrations in the hydrogen-bonded ring.

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Luminol-Dependent Photoemission from Macrophages Stimulated by Cyclic Acetals of Salicylaldehyde

Maślińska-Solich J., Sowa M., Czuba Z.

Polish Journal of Chemistry

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1999

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Vol. 73, nr 8

1339-1343

EN

The synthesis and structure of several cyclic acetals of 2-hydroxybenzaldehyde (salicylaldehyde) and various 1,2- or 1,3-diols are described. These compounds were tested as the enhancers or inhibitors of luminol-dependent chemiluminescence of macrophages.