Encontrados 7 documentos, a visualizar página 1 de 1
Density functional theory study of the oxoperoxo vanadium(V) complexes of glyco...
Justino, Licínia L. G.; Ramos, M. Luísa; Kaupp, Martin; Burrows, Hugh D.; Fiolhais, Carlos; Gil, Victor M. S.The DFT B3LYP/SBKJC method has been used to calculate the gas-phase optimized geometries of the glycolate oxoperoxo vanadium(V) complexes [V2O2(OO)2(gly)2]2-, [V2O3(OO)(gly)2]2- and [VO(OO)(gly)(H2O)]-. The 51V, 17O, 13C and 1H chemical shifts have been calculated for the theoretical geometries in all-electron DFT calculations at the UDFT-IGLO-PW91 level and have been subsequently compared with the experimental...
Conformational Studies of Poly(9,9-dialkylfluorene)s in Solution Using NMR Spec...
Justino, Licínia L. G.; Ramos, M. Luísa; Abreu, Paulo E.; Carvalho, Rui A.; Sobral, Abilio J. F. N.; Scherf, Ullrich; Burrows, Hugh D.Relationships have been obtained between intermonomer torsional angle and NMR chemical shifts (1H and 13C) for isolated chains of two of the most important poly(9,9-dialkylfluorenes), poly[9,9-bis(2-ethylhexyl)fluorene-2,7-diyl] (PF2/6) and the copolymer poly(9,9-dioctylfluorene-co-[2,1,3]benzothiadiazole-4,7-diyl) (F8BT), using DFT calculations. The correlations provide a model for NMR spectral data interpreta...
Density functional theory study of the oxoperoxo vanadium(V) complexes of glyco...
Justino, Licínia L. G.; Ramos, M. Luísa; Kaupp, Martin; Burrows, Hugh D.; Fiolhais, Carlos; Gil, Victor M. S.The DFT B3LYP/SBKJC method has been used to calculate the gas-phase optimized geometries of the glycolate oxoperoxo vanadium(V) complexes [V2O2(OO)2(gly)2]2-, [V2O3(OO)(gly)2]2- and [VO(OO)(gly)(H2O)]-. The 51V, 17O, 13C and 1H chemical shifts have been calculated for the theoretical geometries in all-electron DFT calculations at the UDFT-IGLO-PW91 level and have been subsequently compared with the experimental...
Oxoperoxo Vanadium(V) Complexes of l-Lactic Acid: Density Functional Theory Stu...
Justino, Licínia L. G.; Ramos, M. Luísa; Nogueira, Fernando; Sobral, Abilio J. F. N.; Geraldes, Carlos F. G. C.; Kaupp, Martin; Burrows, Hugh D.Various combinations of density functionals and pseudopotentials with associated valence basis-sets are compared for reproducing the known solid-state structure of [V2O2(OO)2l-lact2]2−cis. Gas-phase optimizations at the B3LYP/SBKJC level have been found to provide a structure that is close to that seen in the solid state by X-ray diffraction. Although this may result in part from error compensation, this optimi...
Oxoperoxo Vanadium(V) Complexes of l-Lactic Acid: Density Functional Theory Stu...
Justino, Licínia L. G.; Ramos, M. Luísa; Nogueira, Fernando; Sobral, Abilio J. F. N.; Geraldes, Carlos F. G. C.; Kaupp, Martin; Burrows, Hugh D.Various combinations of density functionals and pseudopotentials with associated valence basis-sets are compared for reproducing the known solid-state structure of [V2O2(OO)2l-lact2]2−cis. Gas-phase optimizations at the B3LYP/SBKJC level have been found to provide a structure that is close to that seen in the solid state by X-ray diffraction. Although this may result in part from error compensation, this optimi...
Peroxovanadium(V) complexes of glycolic acid as studied by NMR spectroscopy
Justino, Licínia L. G.; Ramos, M. Luísa; Caldeira, M. Madalena; Gil, Victor M. S.Multinuclear (1H, 13C, 17O, 51V) 1D and 2D NMR spectroscopy has been used to characterize the peroxovanadium(V) complexes of glycolic acid in aqueous solution. One 2:2:2 (metal:ligand:peroxo) complex, together with a 1:1:1 and a 2:2:1 species, are found in the pH range 1-7. The 2:2:2 complex is a monoperoxo (one peroxide unit per vanadium atom) dinuclear species having a V2O3 4+ seven-coordinated metal centre. ...
Peroxovanadium(V) Complexes of L-Lactic Acid as Studied by NMR Spectroscopy
Justino, Licínia L. G.; Ramos, M. Luísa; Caldeira, M. Madalena; Gil, Victor M. S.A multinuclear (1H, 13C, 17O, 51V) 1D and 2D NMR study of the complexation of l-lactic acid with vanadium(V) and hydrogen peroxide shows that four peroxo complexes are formed in aqueous solution in the pH range 1-7. Two isomeric 2:2:1 (metal:ligand:peroxo) complexes, together with a 2:2:2 species, are found over the entire pH range. At pH values below 2 an additional 1:1:1 complex is formed. The acid was found ...
| Financiadores do RCAAP | |||||||
|
|
|
|
|
|
||