Protonation of serine conformers, proton affinities and gas-phase basicities at the "gold standard" and beyond /
The potential energy surfaces (PESs) of serine and its protonated counterparts are investigated to determine the structures of the minima. A total of 95 neutral serine, 15 N-(amino-) and 46 O-(carbonyl-)protonated serine conformers are found. Their relative energies, geometries and harmonic vibratio...
Elmentve itt :
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| Dokumentumtípus: | Cikk |
| Megjelent: |
2023
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| Sorozat: | PHYSICAL CHEMISTRY CHEMICAL PHYSICS
25 No. 12 |
| Tárgyszavak: | |
| doi: | 10.1039/d3cp00612c |
| mtmt: | 33732667 |
| Online Access: | http://publicatio.bibl.u-szeged.hu/31853 |
| Tartalmi kivonat: | The potential energy surfaces (PESs) of serine and its protonated counterparts are investigated to determine the structures of the minima. A total of 95 neutral serine, 15 N-(amino-) and 46 O-(carbonyl-)protonated serine conformers are found. Their relative energies, geometries and harmonic vibrational frequencies are determined at the MP2/aug-cc-pVDZ level of theory. To obtain highly accurate thermodynamic values, further computations are performed: the ten conformers with the lowest relative energies from each molecule type (neutral, N- and O-protonated) are further optimized using the explicitly correlated CCSD(T)-F12a/cc-pVDZ-F12 method (for neutral serine, harmonic vibrational frequencies were also computed). In addition, auxiliary corrections were determined: basis-set effects up to CCSD(T)-F12b/cc-pVQZ-F12, electron correlation effects up to CCSDT(Q), core correlation and second-order Douglas-Kroll relativistic effects along with zero-point energy contributions. Two important thermodynamic parameters (at 298.15 K), proton affinity (PA)/gas-phase basicity (GB) are calculated considering the two different protonation sites: 218.05 +/- 0.2/209.86 +/- 0.6 kcal mol(-1) and 205.87 +/- 0.2/196.36 +/- 0.3 kcal mol(-1) for the amino and carbonyl sites, respectively. The uncertainty of the determined values was approximated based on various sources including auxiliary corrections, basis-set effects, harmonic vibrational frequencies. |
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| Terjedelem/Fizikai jellemzők: | 8891-8902 |
| ISSN: | 1463-9076 |