ESE-ENDOR Study and DFT Calculations on Oxovanadium Compounds: Effect of Axial Anionic Ligands on the 51V Nuclear Quadrupolar Coupling Constant.
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| Title: | ESE-ENDOR Study and DFT Calculations on Oxovanadium Compounds: Effect of Axial Anionic Ligands on the 51V Nuclear Quadrupolar Coupling Constant. |
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| Authors: | Aznar, C. P.1, Deligiannakis, Y.1, Tolis, E. J.1, Kabanos, T.1, Brynda, M.1, Britt, R. D.1 |
| Source: | Journal of Physical Chemistry A. May2004, Vol. 108 Issue 19, p4310-4321. 12p. |
| Subjects: | Electrons, Atoms, Organic chemistry, Resonance |
| Abstract: | High-frequency electron spin echo-electron nuclear double resonance (ESE-ENDOR) spectroscopy is applied to oxovanadium VO2+ complexes of Hcapca in the form of trans-[VOX(capca)] and to H2capcah in the form of cis-[VOX(Hcapcah)], where X = Cl- or SCN-. Nuclear quadrupolar coupling constants (nqcc), which are unobtainable by conventional continuous-wave electron paramagnetic resonance (CW-EPR), were measured and reported in terms of P|| (P|| = 3e2qQ/84 for I = 7/2). P|| values for trans-[VOCl(capca)] and trans-[VOSCN(capca)] were calculated to be -0.18 and -0.21 MHz, respectively. In the cases of cis-[VOCl(Hcapcah)] and cis-[VOSCN(Hcapcah), P|| values were calculated to be -0.35 and -0.45 MHz, respectively. The experimental results are supported by DFT calculations of quadrupolar and hyperfine couplings for various oxovanadium compounds, including the cis and trans complexes studied by ESE-ENDOR. The charged ligands, coordinated axially trans to the oxo bond, reduce the electric field gradient along the V=O bond, thereby decreasing the observed magnitude of the nuclear quadrupolar coupling constants relative to those of the comparable cis compounds. This experimental finding is confirmed by quantum mechanical calculations. Although the absolute values of quadrupolar splittings cannot be calculated with acceptable accuracy, the observed experimental trends are very well reproduced. Thus, the complementary use of DFT and pulsed-ENDOR is a promising methodology for the study of biologically relevant vanadyl compounds. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Physical Chemistry A is the property of American Chemical Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 13064125 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: ESE-ENDOR Study and DFT Calculations on Oxovanadium Compounds: Effect of Axial Anionic Ligands on the <superscript>51</superscript>V Nuclear Quadrupolar Coupling Constant. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Aznar%2C+C%2E+P%2E%22">Aznar, C. P.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Deligiannakis%2C+Y%2E%22">Deligiannakis, Y.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Tolis%2C+E%2E+J%2E%22">Tolis, E. J.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Kabanos%2C+T%2E%22">Kabanos, T.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Brynda%2C+M%2E%22">Brynda, M.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Britt%2C+R%2E+D%2E%22">Britt, R. D.</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Physical+Chemistry+A%22">Journal of Physical Chemistry A</searchLink>. May2004, Vol. 108 Issue 19, p4310-4321. 12p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Electrons%22">Electrons</searchLink><br /><searchLink fieldCode="DE" term="%22Atoms%22">Atoms</searchLink><br /><searchLink fieldCode="DE" term="%22Organic+chemistry%22">Organic chemistry</searchLink><br /><searchLink fieldCode="DE" term="%22Resonance%22">Resonance</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: High-frequency electron spin echo-electron nuclear double resonance (ESE-ENDOR) spectroscopy is applied to oxovanadium VO2+ complexes of Hcapca in the form of trans-[VOX(capca)] and to H2capcah in the form of cis-[VOX(Hcapcah)], where X = Cl- or SCN-. Nuclear quadrupolar coupling constants (nqcc), which are unobtainable by conventional continuous-wave electron paramagnetic resonance (CW-EPR), were measured and reported in terms of P|| (P|| = 3e2qQ/84 for I = 7/2). P|| values for trans-[VOCl(capca)] and trans-[VOSCN(capca)] were calculated to be -0.18 and -0.21 MHz, respectively. In the cases of cis-[VOCl(Hcapcah)] and cis-[VOSCN(Hcapcah), P|| values were calculated to be -0.35 and -0.45 MHz, respectively. The experimental results are supported by DFT calculations of quadrupolar and hyperfine couplings for various oxovanadium compounds, including the cis and trans complexes studied by ESE-ENDOR. The charged ligands, coordinated axially trans to the oxo bond, reduce the electric field gradient along the V=O bond, thereby decreasing the observed magnitude of the nuclear quadrupolar coupling constants relative to those of the comparable cis compounds. This experimental finding is confirmed by quantum mechanical calculations. Although the absolute values of quadrupolar splittings cannot be calculated with acceptable accuracy, the observed experimental trends are very well reproduced. Thus, the complementary use of DFT and pulsed-ENDOR is a promising methodology for the study of biologically relevant vanadyl compounds. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Physical Chemistry A is the property of American Chemical Society and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1021/jp037560f Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 12 StartPage: 4310 Subjects: – SubjectFull: Electrons Type: general – SubjectFull: Atoms Type: general – SubjectFull: Organic chemistry Type: general – SubjectFull: Resonance Type: general Titles: – TitleFull: ESE-ENDOR Study and DFT Calculations on Oxovanadium Compounds: Effect of Axial Anionic Ligands on the 51V Nuclear Quadrupolar Coupling Constant. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Aznar, C. P. – PersonEntity: Name: NameFull: Deligiannakis, Y. – PersonEntity: Name: NameFull: Tolis, E. J. – PersonEntity: Name: NameFull: Kabanos, T. – PersonEntity: Name: NameFull: Brynda, M. – PersonEntity: Name: NameFull: Britt, R. D. IsPartOfRelationships: – BibEntity: Dates: – D: 08 M: 05 Text: May2004 Type: published Y: 2004 Identifiers: – Type: issn-print Value: 10895639 Numbering: – Type: volume Value: 108 – Type: issue Value: 19 Titles: – TitleFull: Journal of Physical Chemistry A Type: main |
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