Complexes of pyridoxal thiosemicarbazones formed with vanadium(IV/V) and copper(II): Solution equilibrium and structure

T. Jakusch, Károly Kozma, E. Enyedy, Nóra V. May, Alexander Roller, Christian R. Kowol, Bernhard K. Keppler, T. Kiss

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The stoichiometry and thermodynamic stability of vanadium(IV/V) and copper(II) complexes of pyridoxal thiosemicarbazone and pyridoxal-N3,N3-dimethylthiosemicarbazone have been determined by pH-potentiometry (VIVO), EPR (VIVO/CuII), UV–Vis (CuII, VIVO and VV) and 51V NMR spectroscopy (VV) in 30% (w/w) dimethyl sulfoxide/water solvent mixture. In all cases, mono-ligand complexes are formed in different protonation states. In addition, the proton-dissociation constants of the ligands were also determined by pH-potentiometry, UV–Vis and 1H NMR spectroscopy. The solid state structures of the monoprotonated forms (VVO2(L1H)×1.5H2O and VVO2(L2H)×0.8H2O) of the VV complexes were characterized by single-crystal X-ray diffraction analysis. The mono-ligand complexes of CuII and VV are dominant at physiological pH. With all investigated metal ions the pyridoxal moiety of the ligand causes an extra deprotonation step between pH 4 and 7 due to the non-coordinating pyridine-NH+. The pyridoxal-containing ligands form somewhat more stable complexes with both VIVO and CuII ions than the reference compound salicylaldehyde thiosemicarbazone. Dimethylation of the terminal amino group resulted in the formation of VV and CuII complexes with even higher stability.

Original languageEnglish
Pages (from-to)243-253
Number of pages11
JournalInorganica Chimica Acta
Volume472
DOIs
Publication statusPublished - Mar 1 2018

Fingerprint

Vanadium
vanadium
Copper
Pyridoxal
Ligands
copper
ligands
potentiometric analysis
Nuclear magnetic resonance spectroscopy
nuclear magnetic resonance
Deprotonation
Dimethyl sulfoxide
Protonation
Dimethyl Sulfoxide
Stoichiometry
Pyridine
X ray diffraction analysis
spectroscopy
Metal ions
Paramagnetic resonance

Keywords

  • Copper
  • Pyridoxal
  • Stability constants
  • Thiosemicarbazone
  • Vanadium
  • X-ray crystal structure

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

Cite this

Complexes of pyridoxal thiosemicarbazones formed with vanadium(IV/V) and copper(II) : Solution equilibrium and structure. / Jakusch, T.; Kozma, Károly; Enyedy, E.; May, Nóra V.; Roller, Alexander; Kowol, Christian R.; Keppler, Bernhard K.; Kiss, T.

In: Inorganica Chimica Acta, Vol. 472, 01.03.2018, p. 243-253.

Research output: Contribution to journalArticle

Jakusch, T. ; Kozma, Károly ; Enyedy, E. ; May, Nóra V. ; Roller, Alexander ; Kowol, Christian R. ; Keppler, Bernhard K. ; Kiss, T. / Complexes of pyridoxal thiosemicarbazones formed with vanadium(IV/V) and copper(II) : Solution equilibrium and structure. In: Inorganica Chimica Acta. 2018 ; Vol. 472. pp. 243-253.
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T1 - Complexes of pyridoxal thiosemicarbazones formed with vanadium(IV/V) and copper(II)

T2 - Solution equilibrium and structure

AU - Jakusch, T.

AU - Kozma, Károly

AU - Enyedy, E.

AU - May, Nóra V.

AU - Roller, Alexander

AU - Kowol, Christian R.

AU - Keppler, Bernhard K.

AU - Kiss, T.

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N2 - The stoichiometry and thermodynamic stability of vanadium(IV/V) and copper(II) complexes of pyridoxal thiosemicarbazone and pyridoxal-N3,N3-dimethylthiosemicarbazone have been determined by pH-potentiometry (VIVO), EPR (VIVO/CuII), UV–Vis (CuII, VIVO and VV) and 51V NMR spectroscopy (VV) in 30% (w/w) dimethyl sulfoxide/water solvent mixture. In all cases, mono-ligand complexes are formed in different protonation states. In addition, the proton-dissociation constants of the ligands were also determined by pH-potentiometry, UV–Vis and 1H NMR spectroscopy. The solid state structures of the monoprotonated forms (VVO2(L1H)×1.5H2O and VVO2(L2H)×0.8H2O) of the VV complexes were characterized by single-crystal X-ray diffraction analysis. The mono-ligand complexes of CuII and VV are dominant at physiological pH. With all investigated metal ions the pyridoxal moiety of the ligand causes an extra deprotonation step between pH 4 and 7 due to the non-coordinating pyridine-NH+. The pyridoxal-containing ligands form somewhat more stable complexes with both VIVO and CuII ions than the reference compound salicylaldehyde thiosemicarbazone. Dimethylation of the terminal amino group resulted in the formation of VV and CuII complexes with even higher stability.

AB - The stoichiometry and thermodynamic stability of vanadium(IV/V) and copper(II) complexes of pyridoxal thiosemicarbazone and pyridoxal-N3,N3-dimethylthiosemicarbazone have been determined by pH-potentiometry (VIVO), EPR (VIVO/CuII), UV–Vis (CuII, VIVO and VV) and 51V NMR spectroscopy (VV) in 30% (w/w) dimethyl sulfoxide/water solvent mixture. In all cases, mono-ligand complexes are formed in different protonation states. In addition, the proton-dissociation constants of the ligands were also determined by pH-potentiometry, UV–Vis and 1H NMR spectroscopy. The solid state structures of the monoprotonated forms (VVO2(L1H)×1.5H2O and VVO2(L2H)×0.8H2O) of the VV complexes were characterized by single-crystal X-ray diffraction analysis. The mono-ligand complexes of CuII and VV are dominant at physiological pH. With all investigated metal ions the pyridoxal moiety of the ligand causes an extra deprotonation step between pH 4 and 7 due to the non-coordinating pyridine-NH+. The pyridoxal-containing ligands form somewhat more stable complexes with both VIVO and CuII ions than the reference compound salicylaldehyde thiosemicarbazone. Dimethylation of the terminal amino group resulted in the formation of VV and CuII complexes with even higher stability.

KW - Copper

KW - Pyridoxal

KW - Stability constants

KW - Thiosemicarbazone

KW - Vanadium

KW - X-ray crystal structure

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