The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study
The previously unreported equilibrium in aqueous solution between the (VO)-O-IV 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...
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ftsassariuniiris:oai:iris.uniss.it:11388/50062 2024-04-14T08:18:01+00:00 The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study S. GORELSKY G. MICERA GARRIBBA, Eugenio S., Gorelsky G., Micera Garribba, Eugenio 2010 http://hdl.handle.net/11388/50062 https://doi.org/10.1002/chem.201000679 http://onlinelibrary.wiley.com/doi/10.1002/chem.201000679/abstract;jsessionid=F81AE707E09D207D76CDFFAB1AEAA6A8.d03t02 eng eng info:eu-repo/semantics/altIdentifier/wos/WOS:000280626000032 volume:16 firstpage:8167 lastpage:8180 numberofpages:14 journal:CHEMISTRY-A EUROPEAN JOURNAL http://hdl.handle.net/11388/50062 doi:10.1002/chem.201000679 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-77954702554 http://onlinelibrary.wiley.com/doi/10.1002/chem.201000679/abstract;jsessionid=F81AE707E09D207D76CDFFAB1AEAA6A8.d03t02 info:eu-repo/semantics/article 2010 ftsassariuniiris https://doi.org/10.1002/chem.201000679 2024-03-15T04:12:02Z The previously unreported equilibrium in aqueous solution between the (VO)-O-IV 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(1H)-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 penta-coordinated species and values of K approximate to 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 V-51 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 V=O bond. The results suggest that an axial donor (charged or not) can lower vertical bar A(z)vertical bar, in contrast to what was previously believed on the basis of the "additivity rule", and this explains the anomalous behaviour of the (VO)-O-IV complexes formed by N-{2- [(2-pyridylmethylene)amino]phenyl}-pyridine-2-carboxamide (Hcapca) and several amidrazone derivatives. The decrease in vertical bar A(z)vertical bar for the axial binding of a solvent molecule is mainly a result of the reduction of vertical bar A(iso)vertical bar and this was also observed when the solid [VO(6-methylpicolinato)(2)] was dissolved in DMSO or DMF. The variations in the structural (V=O, V-O and V-N distances, O-V-O and N-V-N angles, and the trigonality index tau) and spectroscopic (vertical bar A(z)vertical bar, vertical bar A(iso)vertical bar and v(V=O)) properties as a function of the axial V-OH2 distance (R) are also presented. Finally, the electronic structures of the penta-and hexacoordinated complexes are discussed. Article in Journal/Newspaper Orca CINECA IRIS Universitá Degli Studi di Sassari Chemistry - A European Journal 16 27 8167 8180 |
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CINECA IRIS Universitá Degli Studi di Sassari |
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English |
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The previously unreported equilibrium in aqueous solution between the (VO)-O-IV 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(1H)-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 penta-coordinated species and values of K approximate to 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 V-51 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 V=O bond. The results suggest that an axial donor (charged or not) can lower vertical bar A(z)vertical bar, in contrast to what was previously believed on the basis of the "additivity rule", and this explains the anomalous behaviour of the (VO)-O-IV complexes formed by N-{2- [(2-pyridylmethylene)amino]phenyl}-pyridine-2-carboxamide (Hcapca) and several amidrazone derivatives. The decrease in vertical bar A(z)vertical bar for the axial binding of a solvent molecule is mainly a result of the reduction of vertical bar A(iso)vertical bar and this was also observed when the solid [VO(6-methylpicolinato)(2)] was dissolved in DMSO or DMF. The variations in the structural (V=O, V-O and V-N distances, O-V-O and N-V-N angles, and the trigonality index tau) and spectroscopic (vertical bar A(z)vertical bar, vertical bar A(iso)vertical bar and v(V=O)) properties as a function of the axial V-OH2 distance (R) are also presented. Finally, the electronic structures of the penta-and hexacoordinated complexes are discussed. |
author2 |
S., Gorelsky G., Micera Garribba, Eugenio |
format |
Article in Journal/Newspaper |
author |
S. GORELSKY G. MICERA GARRIBBA, Eugenio |
spellingShingle |
S. GORELSKY G. MICERA GARRIBBA, Eugenio The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study |
author_facet |
S. GORELSKY G. MICERA GARRIBBA, Eugenio |
author_sort |
S. GORELSKY |
title |
The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study |
title_short |
The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study |
title_full |
The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study |
title_fullStr |
The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study |
title_full_unstemmed |
The equilibrium between the octahedral and square pyramidal form in VIVO complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and DFT study |
title_sort |
equilibrium between the octahedral and square pyramidal form in vivo complexes and the influence of an axial ligand on their molecular properties: a spectroscopic and dft study |
publishDate |
2010 |
url |
http://hdl.handle.net/11388/50062 https://doi.org/10.1002/chem.201000679 http://onlinelibrary.wiley.com/doi/10.1002/chem.201000679/abstract;jsessionid=F81AE707E09D207D76CDFFAB1AEAA6A8.d03t02 |
genre |
Orca |
genre_facet |
Orca |
op_relation |
info:eu-repo/semantics/altIdentifier/wos/WOS:000280626000032 volume:16 firstpage:8167 lastpage:8180 numberofpages:14 journal:CHEMISTRY-A EUROPEAN JOURNAL http://hdl.handle.net/11388/50062 doi:10.1002/chem.201000679 info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-77954702554 http://onlinelibrary.wiley.com/doi/10.1002/chem.201000679/abstract;jsessionid=F81AE707E09D207D76CDFFAB1AEAA6A8.d03t02 |
op_doi |
https://doi.org/10.1002/chem.201000679 |
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Chemistry - A European Journal |
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8167 |
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