Ganyecz Ádám, Kállay Mihály, Csontos József
Department of Physical Chemistry and Materials Science , Budapest University of Technology and Economics , Budapest , PO Box 91, H-1521 , Hungary.
J Phys Chem A. 2019 May 9;123(18):4057-4067. doi: 10.1021/acs.jpca.9b02061. Epub 2019 Apr 26.
The goal of this study is to give reliable and accurate thermochemical data for uracil, thymine, cytosine, and adenine. The gas-phase heats of formation of these compounds were determined with the diet-HEAT-F12 protocol, which uses explicitly correlated coupled-cluster calculations along with anharmonic vibrational, scalar relativistic, and diagonal Born-Oppenheimer corrections. The thermochemically relevant tautomers of cytosine were also investigated. To derive heats of formation in the gas and solid phases as well as sublimation enthalpies, the thermochemical network approach was utilized, i.e., the available literature data were collected, reviewed, and combined with our theoretical calculations. Solvation free energies were also determined with various methods and compared to experimental data.
本研究的目的是提供关于尿嘧啶、胸腺嘧啶、胞嘧啶和腺嘌呤可靠且准确的热化学数据。这些化合物的气相生成热是通过diet-HEAT-F12协议测定的，该协议使用显式相关耦合簇计算以及非谐振动、标量相对论和对角玻恩-奥本海默校正。还研究了胞嘧啶的热化学相关互变异构体。为了推导气相和固相的生成热以及升华焓，采用了热化学网络方法，即收集、审查现有的文献数据，并将其与我们的理论计算相结合。还使用各种方法测定了溶剂化自由能，并与实验数据进行了比较。
