Abstract
The protonation of pyrazine is investigated by geometry optimization. Ab initio calculations were carried out for the neutral pyrazine molecule, the pyrazine monocation and the pyrazine bication, using the Gaussian 80 program with a minimal (STO-3G) basis set. Similar calculations were also performed with the CNDO/force method. The results for pyrazine show that in some cases CNDO results are nearer to the experimental data than the ab initio ones. According to the ab initio calculations both CH and NH bonds are lengthened by the proton gains. The NC bond lengthens stepwise, but the CC bond only lengthens at the second protonation. The CNC and NCH angles increase and the NCC and CNH angles decrease upon protonation. The Mulliken population analysis shows that the ring bond lengths depend on the 2pπ - 2pπ overlap densities, the CNC angles on the 2(px + py)/2s population ratio on the nitrogen, while the NCC angles depend on the π charges on the carbon atom.
| Original language | English |
|---|---|
| Pages (from-to) | 289-295 |
| Number of pages | 7 |
| Journal | Journal of Molecular Structure: THEOCHEM |
| Volume | 149 |
| Issue number | 3-4 |
| DOIs | |
| Publication status | Published - 1987 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Computational Theory and Mathematics
- Atomic and Molecular Physics, and Optics
Cite this
Quantum-chemical study on the successive protonation of pyrazine. / Billes, F.
In: Journal of Molecular Structure: THEOCHEM, Vol. 149, No. 3-4, 1987, p. 289-295.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Quantum-chemical study on the successive protonation of pyrazine
AU - Billes, F.
PY - 1987
Y1 - 1987
N2 - The protonation of pyrazine is investigated by geometry optimization. Ab initio calculations were carried out for the neutral pyrazine molecule, the pyrazine monocation and the pyrazine bication, using the Gaussian 80 program with a minimal (STO-3G) basis set. Similar calculations were also performed with the CNDO/force method. The results for pyrazine show that in some cases CNDO results are nearer to the experimental data than the ab initio ones. According to the ab initio calculations both CH and NH bonds are lengthened by the proton gains. The NC bond lengthens stepwise, but the CC bond only lengthens at the second protonation. The CNC and NCH angles increase and the NCC and CNH angles decrease upon protonation. The Mulliken population analysis shows that the ring bond lengths depend on the 2pπ - 2pπ overlap densities, the CNC angles on the 2(px + py)/2s population ratio on the nitrogen, while the NCC angles depend on the π charges on the carbon atom.
AB - The protonation of pyrazine is investigated by geometry optimization. Ab initio calculations were carried out for the neutral pyrazine molecule, the pyrazine monocation and the pyrazine bication, using the Gaussian 80 program with a minimal (STO-3G) basis set. Similar calculations were also performed with the CNDO/force method. The results for pyrazine show that in some cases CNDO results are nearer to the experimental data than the ab initio ones. According to the ab initio calculations both CH and NH bonds are lengthened by the proton gains. The NC bond lengthens stepwise, but the CC bond only lengthens at the second protonation. The CNC and NCH angles increase and the NCC and CNH angles decrease upon protonation. The Mulliken population analysis shows that the ring bond lengths depend on the 2pπ - 2pπ overlap densities, the CNC angles on the 2(px + py)/2s population ratio on the nitrogen, while the NCC angles depend on the π charges on the carbon atom.
UR - http://www.scopus.com/inward/record.url?scp=0346731979&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0346731979&partnerID=8YFLogxK
U2 - 10.1016/0166-1280(87)87028-8
DO - 10.1016/0166-1280(87)87028-8
M3 - Article
AN - SCOPUS:0346731979
VL - 149
SP - 289
EP - 295
JO - Computational and Theoretical Chemistry
JF - Computational and Theoretical Chemistry
SN - 2210-271X
IS - 3-4
ER -