NMR and theoretical investigations on the structures and dynamics of octahedral bis(chelate)dichloro V-III compounds isolated by an unusual reduction of non-oxo V-IV species
| dc.contributor.author | Rikkou, M. | en |
| dc.contributor.author | Manos, M. | en |
| dc.contributor.author | Tolis, E. | en |
| dc.contributor.author | Sigalas, M. P. | en |
| dc.contributor.author | Kabanos, T. A. | en |
| dc.contributor.author | Keramidas, A. D. | en |
| dc.date.accessioned | 2015-11-24T16:42:46Z | |
| dc.date.available | 2015-11-24T16:42:46Z | |
| dc.identifier.issn | 0020-1669 | - |
| dc.identifier.uri | https://olympias.lib.uoi.gr/jspui/handle/123456789/8592 | |
| dc.rights | Default Licence | - |
| dc.subject | effective core potentials | en |
| dc.subject | tris-chelate complexes | en |
| dc.subject | ray-absorption spectroscopy | en |
| dc.subject | nuclear magnetic-resonance | en |
| dc.subject | tunicate ascidia ceratodes | en |
| dc.subject | configurational rearrangements | en |
| dc.subject | molecular calculations | en |
| dc.subject | hydrogen-peroxide | en |
| dc.subject | DNA cleavage | en |
| dc.subject | blood-cells | en |
| dc.title | NMR and theoretical investigations on the structures and dynamics of octahedral bis(chelate)dichloro V-III compounds isolated by an unusual reduction of non-oxo V-IV species | en |
| heal.abstract | Reaction of the non-oxo V-IV species [(VCl2)-Cl-IV(L-OO)(2)] [L-OO = acetylacetonate (acac(-)) or benzoylacetonate (bzac(-))] with a chelate nitrogen-donor ligand L-NN in acetonitrile leads to the reduction of V-IV to V-III and the formation of the mononuclear V-III compounds of the general formula [(VCl2)-Cl-III(L-OO)(L-NN)] (L-OO and L-NN are acac(-) and bipy for 1; acac- and 5,5'-me(2)bipy for 2; acac- and 4,4'-tb(2)bipy for 3; acac(-) and phen for 4; bzac(-) and bipy for 5; bzac(-) and phen for 6). The reduction of the V-IV complexes was monitored by GC-MS and H-1 NMR spectroscopy. Both one- and two-dimensional (2D COSY and 2D EXSY) H-1 NMR techniques were used to assign the observed 1H NMR resonances of 1-6 in CD2Cl2 or CDCl3 solution. It appeared that in solution these V-III complexes form two isomers which are in equilibrium: cis-[(VCl2)-Cl-III(L-OO)(L-NN)] reversible arrow trans-[(VCl2)-Cl-III(L-OO)(L-NN)]. 2D EXSY cross-peaks were clearly observed between bipy- and acac-hydrogen atoms of the two geometrical isomers of 1-3 as well as between bipy and acac(-) protons of the cis isomer, indicating a dynamic process that corresponds to cis-trans isomerization and a cis-cis racemization. The thermodynamic and kinetic parameters of the equilibrium between these two isomers were calculated for compounds 1 and 2 by using variable temperature (VT) NMR data. Both cis-trans isomerization and cis-cis racemization processes probably proceed with an intramolecular twist mechanism involving a trigonal prismatic transition state. Density functional calculations (DFT) also indicated such a rearrangement mechanism. | en |
| heal.access | campus | - |
| heal.fullTextAvailability | TRUE | - |
| heal.identifier.primary | Doi 10.1021/Ic034221s | - |
| heal.identifier.secondary | <Go to ISI>://000184264400028 | - |
| heal.identifier.secondary | http://pubs.acs.org/doi/pdfplus/10.1021/ic034221s | - |
| heal.journalName | Inorg Chem | en |
| heal.journalType | peer reviewed | - |
| heal.language | en | - |
| heal.publicationDate | 2003 | - |
| heal.publisher | American Chemical Society | en |
| heal.recordProvider | Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας | el |
| heal.type | journalArticle | - |
| heal.type.el | Άρθρο Περιοδικού | el |
| heal.type.en | Journal article | en |
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