TY  - JOUR
SN  - 1463-9076
VL  - 25
JF  - PHYSICAL CHEMISTRY CHEMICAL PHYSICS
EP  - 8902
IS  - 12
ID  - publicatio31853
Y1  - 2023///
UR  - https://doi.org/10.1039/d3cp00612c
N1  - Funding Agency and Grant Number: National Research, Development and Innovation Office-NKFIH [K-125317, TKP2021-NVA-19]; Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund [TKP2021-NVA]; Momentum (Lenduelet) Program of the Hungarian Academy of Sciences
            Funding text: We thank the National Research, Development and Innovation Office-NKFIH, K-125317; Project no. TKP2021-NVA-19, provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NVA funding scheme; and the Momentum (Lenduelet) Program of the Hungarian Academy of Sciences for financial support.
AV  - public
N2  - 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.
A1  -  Nacsa András Bence
A1  -  Kigyosi Mate
A1  -  Czakó Gábor
TI  - Protonation of serine: conformers, proton affinities and gas-phase basicities at the "gold standard" and beyond
SP  - 8891
ER  -