| Autor: |
A Es-sofi, A. Ouassas, A. Boutalib, Chafiq Serrar |
| Rok vydání: |
1999 |
| Předmět: |
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| Zdroj: |
Journal of Molecular Structure: THEOCHEM. 492:197-202 |
| ISSN: |
0166-1280 |
| DOI: |
10.1016/s0166-1280(99)00163-3 |
| Popis: |
The structural complexity and chemical stability of the oxaborate [B11H12O]− ion made us use a quantum chemical calculation which is an indispensable tool to complete the experimental data. Therefore, we have optimised the geometries of six possible structures of the anion [B11H12O]− using the semi-empirical method AM1. The latter method gives satisfactory results for the boron clusters. A comparison of the heat of formation and the frontier molecular orbital energies shows that the most stable structure is that where the oxygen atom is bound to three boron atoms in the open face of the cage. This structure is in good agreement with that proposed by analysing NMR spectrum data. We have also calculated the B–B, B–H and B–O bond lengths, the bond index and the charge distribution for this conformation. Finally, we have theoretically studied the isomerisation mechanism of the stablest structure in order to obtain the other structures. The highest activation barrier energy calculated for the first stage explains the stability of this compound. The isomerisation of the stablest isomer of the [B11H12O]− ion is found to occur by the migration of the bridged hydrogen on to the oxygen atom in order to provide the stablest conformation containing the OH function. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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