%0 Journal Article
%@ 1463-9076
%A  Nacsa András Bence
%A  Kigyosi Mate
%A  Czakó Gábor
%A Fizikai Kémiai és Anyagtudományi Tanszék SZTE / TTIK / KI FKAT [2016-],
%A MTA-SZTE Lendület Elméleti Reakciódinamika Kutatócsoport SZTE / TTIK / KI / FKAT [2019-],
%D 2023
%F publicatio:31853
%J PHYSICAL CHEMISTRY CHEMICAL PHYSICS
%N 12
%P 8891-8902
%T Protonation of serine: conformers, proton affinities and gas-phase basicities at the "gold standard" and beyond
%U http://publicatio.bibl.u-szeged.hu/31853/
%V 25
%X 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.
%Z 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.