基准甘氨酸的质子亲和力。
Benchmark proton affinity of glycine.
机构信息
MTA-SZTE Lendület Computational Reaction Dynamics Research Group, Interdisciplinary Excellence Centre and Department of Physical Chemistry and Materials Science, Institute of Chemistry, University of Szeged, Rerrich Béla tér 1, Szeged H-6720, Hungary.
出版信息
Phys Chem Chem Phys. 2021 Apr 28;23(16):9663-9671. doi: 10.1039/d1cp00376c.
A systematic conformational search reveals three N- (amino) and eight O- (carbonyl) protonated glycine conformers with benchmark equilibrium(adiabatic) relative energies in the 0.00-7.51(0.00-7.37) and 25.91-31.61(24.45-30.28) kcal mol-1 ranges, respectively. Benchmark ab initio structures of the glycine conformers and its protonated species are obtained at the CCSD(T)-F12b/aug-cc-pVTZ level of theory and the relative energy computations consider basis-set effects up to aug-cc-pVQZ with CCSD(T)-F12b, electron correlation up to CCSDT(Q), core correlation corrections, scalar relativistic effects, and zero-point energy contributions. The best predictions for Boltzmann-averaged 0(298.15) K proton affinities and [298.15 K gas-phase basicities] of glycine are 211.00(212.43)[204.75] and 186.38(187.64)[180.21] kcal mol-1 for N- and O-protonation, respectively, in excellent agreement with experiments.
通过系统的构象搜索，揭示了三种 N-（氨基）和八种 O-（羰基）质子化甘氨酸构象，在 0.00-7.51（0.00-7.37）和 25.91-31.61（24.45-30.28）千卡/摩尔的范围内，具有基准平衡（绝热）相对能量。在 CCSD(T)-F12b/aug-cc-pVTZ 理论水平上获得了甘氨酸构象及其质子化物种的基准从头算结构，并且相对能量计算考虑了截至 aug-cc-pVQZ 的基组效应，以及 CCSDT(Q)的电子相关、核相关修正、标量相对论效应和零点能贡献。对于 0（298.15）K 条件下的质子亲和能和[298.15 K 气相碱度]的最佳 Boltzmann 平均预测值，N-和 O-质子化甘氨酸分别为 211.00（212.43）[204.75]和 186.38（187.64）[180.21]千卡/摩尔，与实验结果非常吻合。
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