Abstract
The mechanism for the hydrolysis of the methyl phosphate anion was studied using high-level ab itiitio and density functional theory methods. Starting from the molecular species CH3OPO3H-, CH3OP3H-·(H2O), and CH3OPO3H-(H2O)2, gas phase reaction coordinates of the proposed mechanisms were followed. Solvation free energies were evaluated using the polarizable continuum model (PCM) at the stationary point geometries. The dissociative mechanism, which involves the formation of a metaphosphate ion (PO3 -), is found to be more favorable than the associative mechanism, which involves a pentacoordinated intermediate, both in the gas phase and in aqueous solution. In the dissociative mechanism, the first step is rate determining. The computed free energy of activation in solution is within 1.7 kcal/mol of the experimentally determined activation free energy for hydrolysis. The first step and the second step in the dissociative mechanism are each shown to proceed via a six-centered water-assisted transition state.
| Original language | English |
|---|---|
| Pages (from-to) | 5379-5386 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry A |
| Volume | 103 |
| Issue number | 27 |
| DOIs | |
| Publication status | Published - 1999 Jul 8 |
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All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
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Theoretical Studies of the Hydrolysis of the Methyl Phosphate Anion. / Hu, Ching Han; Brinck, Tore.
In: Journal of Physical Chemistry A, Vol. 103, No. 27, 08.07.1999, p. 5379-5386.Research output: Contribution to journal › Article
TY - JOUR
T1 - Theoretical Studies of the Hydrolysis of the Methyl Phosphate Anion
AU - Hu, Ching Han
AU - Brinck, Tore
PY - 1999/7/8
Y1 - 1999/7/8
N2 - The mechanism for the hydrolysis of the methyl phosphate anion was studied using high-level ab itiitio and density functional theory methods. Starting from the molecular species CH3OPO3H-, CH3OP3H-·(H2O), and CH3OPO3H-(H2O)2, gas phase reaction coordinates of the proposed mechanisms were followed. Solvation free energies were evaluated using the polarizable continuum model (PCM) at the stationary point geometries. The dissociative mechanism, which involves the formation of a metaphosphate ion (PO3 -), is found to be more favorable than the associative mechanism, which involves a pentacoordinated intermediate, both in the gas phase and in aqueous solution. In the dissociative mechanism, the first step is rate determining. The computed free energy of activation in solution is within 1.7 kcal/mol of the experimentally determined activation free energy for hydrolysis. The first step and the second step in the dissociative mechanism are each shown to proceed via a six-centered water-assisted transition state.
AB - The mechanism for the hydrolysis of the methyl phosphate anion was studied using high-level ab itiitio and density functional theory methods. Starting from the molecular species CH3OPO3H-, CH3OP3H-·(H2O), and CH3OPO3H-(H2O)2, gas phase reaction coordinates of the proposed mechanisms were followed. Solvation free energies were evaluated using the polarizable continuum model (PCM) at the stationary point geometries. The dissociative mechanism, which involves the formation of a metaphosphate ion (PO3 -), is found to be more favorable than the associative mechanism, which involves a pentacoordinated intermediate, both in the gas phase and in aqueous solution. In the dissociative mechanism, the first step is rate determining. The computed free energy of activation in solution is within 1.7 kcal/mol of the experimentally determined activation free energy for hydrolysis. The first step and the second step in the dissociative mechanism are each shown to proceed via a six-centered water-assisted transition state.
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U2 - 10.1021/jp9835061
DO - 10.1021/jp9835061
M3 - Article
VL - 103
SP - 5379
EP - 5386
JO - Journal of Physical Chemistry A
JF - Journal of Physical Chemistry A
SN - 1089-5639
IS - 27
ER -