The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study
Abstract The previously unreported equilibrium in aqueous solution between the V IV O square pyramidal and trans octahedral form with an axial water molecule for a number of bidentate ligands with (N,O) and (O,O) donor sets (6‐methylpicolinic (6‐mepicH) and 6‐methyl‐2,3‐pyridinedicarboxylic (6‐me‐2,...
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crwiley:10.1002/chem.201000679 2024-06-02T08:12:49+00:00 The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study Gorelsky, Serge Micera, Giovanni Garribba, Eugenio 2010 http://dx.doi.org/10.1002/chem.201000679 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fchem.201000679 https://onlinelibrary.wiley.com/doi/full/10.1002/chem.201000679 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Chemistry – A European Journal volume 16, issue 27, page 8167-8180 ISSN 0947-6539 1521-3765 journal-article 2010 crwiley https://doi.org/10.1002/chem.201000679 2024-05-03T11:17:32Z Abstract The previously unreported equilibrium in aqueous solution between the V IV O square pyramidal and trans octahedral form with an axial water molecule for a number of bidentate ligands with (N,O) and (O,O) donor sets (6‐methylpicolinic (6‐mepicH) and 6‐methyl‐2,3‐pyridinedicarboxylic (6‐me‐2,3‐pdcH 2 ) acids, dipyridin‐2‐ylmethanol (Hdpmo) and 1,2‐dimethyl‐3‐hydroxy‐4(1 H )‐pyridinone (Hdhp)) has been demonstrated by the combined application of EPR spectroscopy and DFT methods. The EPR spectra suggest that, with increasing ionic strength, the equilibrium is shifted towards the formation of the pentacoordinated species and values of K ≈4.0 and 7.0 for the systems containing 6‐methyl‐2,3‐pyridinedicarboxylic acid and dipyridin‐2‐ylmethanol were measured. DFT calculations performed with Gaussian 03 and ORCA software predict the 51 V anisotropic hyperfine coupling constant along the z axis ( A z ), which can be used to demonstrate the presence of an axially bound ligand trans to the VO bond. The results suggest that an axial donor (charged or not) can lower | A z |, in contrast to what was previously believed on the basis of the “additivity rule”, and this explains the anomalous behaviour of the V IV O complexes formed by N ‐{2‐[(2‐pyridylmethylene)amino]phenyl}pyridine‐2‐carboxamide (Hcapca) and several amidrazone derivatives. The decrease in | A z | for the axial binding of a solvent molecule is mainly a result of the reduction of | A iso | and this was also observed when the solid [VO(6‐methylpicolinato) 2 ] was dissolved in DMSO or DMF. The variations in the structural (VO, VO and VN distances, OVO and NVN angles, and the trigonality index τ ) and spectroscopic (| A z |, | A iso | and ν (VO)) properties as a function of the axial VOH 2 distance ( R ) are also presented. Finally, the electronic structures of the penta‐ and hexacoordinated complexes are discussed. Article in Journal/Newspaper Orca Wiley Online Library Chemistry – A European Journal 16 27 8167 8180 |
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Abstract The previously unreported equilibrium in aqueous solution between the V IV O square pyramidal and trans octahedral form with an axial water molecule for a number of bidentate ligands with (N,O) and (O,O) donor sets (6‐methylpicolinic (6‐mepicH) and 6‐methyl‐2,3‐pyridinedicarboxylic (6‐me‐2,3‐pdcH 2 ) acids, dipyridin‐2‐ylmethanol (Hdpmo) and 1,2‐dimethyl‐3‐hydroxy‐4(1 H )‐pyridinone (Hdhp)) has been demonstrated by the combined application of EPR spectroscopy and DFT methods. The EPR spectra suggest that, with increasing ionic strength, the equilibrium is shifted towards the formation of the pentacoordinated species and values of K ≈4.0 and 7.0 for the systems containing 6‐methyl‐2,3‐pyridinedicarboxylic acid and dipyridin‐2‐ylmethanol were measured. DFT calculations performed with Gaussian 03 and ORCA software predict the 51 V anisotropic hyperfine coupling constant along the z axis ( A z ), which can be used to demonstrate the presence of an axially bound ligand trans to the VO bond. The results suggest that an axial donor (charged or not) can lower | A z |, in contrast to what was previously believed on the basis of the “additivity rule”, and this explains the anomalous behaviour of the V IV O complexes formed by N ‐{2‐[(2‐pyridylmethylene)amino]phenyl}pyridine‐2‐carboxamide (Hcapca) and several amidrazone derivatives. The decrease in | A z | for the axial binding of a solvent molecule is mainly a result of the reduction of | A iso | and this was also observed when the solid [VO(6‐methylpicolinato) 2 ] was dissolved in DMSO or DMF. The variations in the structural (VO, VO and VN distances, OVO and NVN angles, and the trigonality index τ ) and spectroscopic (| A z |, | A iso | and ν (VO)) properties as a function of the axial VOH 2 distance ( R ) are also presented. Finally, the electronic structures of the penta‐ and hexacoordinated complexes are discussed. |
format |
Article in Journal/Newspaper |
author |
Gorelsky, Serge Micera, Giovanni Garribba, Eugenio |
spellingShingle |
Gorelsky, Serge Micera, Giovanni Garribba, Eugenio The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study |
author_facet |
Gorelsky, Serge Micera, Giovanni Garribba, Eugenio |
author_sort |
Gorelsky, Serge |
title |
The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study |
title_short |
The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study |
title_full |
The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study |
title_fullStr |
The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study |
title_full_unstemmed |
The Equilibrium Between the Octahedral and Square Pyramidal Form and the Influence of an Axial Ligand on the Molecular Properties of V IV O Complexes: A Spectroscopic and DFT Study |
title_sort |
equilibrium between the octahedral and square pyramidal form and the influence of an axial ligand on the molecular properties of v iv o complexes: a spectroscopic and dft study |
publisher |
Wiley |
publishDate |
2010 |
url |
http://dx.doi.org/10.1002/chem.201000679 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fchem.201000679 https://onlinelibrary.wiley.com/doi/full/10.1002/chem.201000679 |
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Orca |
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Orca |
op_source |
Chemistry – A European Journal volume 16, issue 27, page 8167-8180 ISSN 0947-6539 1521-3765 |
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http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/chem.201000679 |
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Chemistry – A European Journal |
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16 |
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27 |
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8167 |
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8180 |
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1800759378621497344 |