A theoretical study on the gas phase reactions of the anions NbO3-, NbO5-, and NbO2(0H)(2)(-) with H2O and O-2


Autoria(s): Sambrano, JR; Gracia, L.; Andres, J.; Berski, S.; Beltran, A.
Contribuinte(s)

Universidade Estadual Paulista (UNESP)

Data(s)

20/05/2014

20/05/2014

09/12/2004

Resumo

The potential energy surfaces at the singlet (s) and the triplet (t) electronic states associated with the gas-phase ion/molecule reactions of NbO3-, NbO5-, and NbO2(OH)(2)(-) with H2O and O-2 have been investigated by means of DFT calculations at the B3LYP level. An analysis of the results points out that the most favorable reactive channel comprises s-NbO3- reacting with H2O to give an ion-molecule complex s-NbO3(H2O)without a barrier. From this minima, an intramolecular hydrogen transfer takes place between the incoming water molecule and an oxygen atom of the NbO3- fragment to render the most stable minimum, s-NbO2(OH)(2)(-). This oxyhydroxide system reacts with O-2 along a barrierless process to obtain the triplet t-NbO4(OH)(2)(-)-A intermediate, and the crossing point, CP1, between s and t electronic states has been characterized. The next step is the hydrogen-transfer process between the oxygen atom of a hydroxyl group and the one adjacent oxygen atom to render a minimum with the two OH groups near each other, t-NbO4(OH)(2)(-)-B. From this point, the last hydrogen migration takes place, to obtain the product complex, t-NbO5(H2O)(-), that can be connected with the singlet separated products, s-NbO5- and H2O. Therefore, a second crossing point, CP2, has been localized. The nature of the chemical bonding of the key minima (NbO3-, NbO2(OH)(2)(-), NbO4(OH)(2)(-)-B, and NbO5-) in both electronic states of the reaction and an interaction with O-2 has been studied by topological analysis of Becke-Edgecombe electron-localization function (ELF) and atoms-in-molecules (AIM) methodology. The niobium-oxygen interactions are characterized as unshared-electron (ionic) interactions and some oxygen-oxygen interactions as protocovalent bonds.

Formato

10850-10860

Identificador

http://dx.doi.org/10.1021/jp047229b

Journal of Physical Chemistry A. Washington: Amer Chemical Soc, v. 108, n. 49, p. 10850-10860, 2004.

1089-5639

http://hdl.handle.net/11449/8552

10.1021/jp047229b

WOS:000225548900012

Idioma(s)

eng

Publicador

Amer Chemical Soc

Relação

Journal of Physical Chemistry A

Direitos

closedAccess

Tipo

info:eu-repo/semantics/article