Belova Natalya V, Oberhammer Heinz, Trang Nguen Hoang, Girichev Georgiy V
Research Institute for Thermodynamics and Kinetics of Chemical Processes, Ivanovo State University of Chemistry and Technology , 153460 Ivanovo, Russia.
J Org Chem. 2014 Jun 20;79(12):5412-9. doi: 10.1021/jo402814c. Epub 2014 May 29.
The tautomeric and structural properties of acetylacetone, CH3C(O)CH2C(O)CH3, have been studied by gas-phase electron diffraction (GED) and quantum chemical calculations (B3LYP and MP2 approximation with different basis sets up to aug-cc-pVTZ). The analysis of GED intensities resulted in the presence of 100(3)% of the enol tautomer at 300(5) K and 64(5)% of the enol at 671(7) K. The enol tautomer possesses Cs symmetry with a planar ring and strongly asymmetric hydrogen bond. The diketo form possesses C2 symmetry. The experimental geometric parameters of both tautomeric forms are reproduced very closely by B3LYP/aug-cc-pVTZ and MP2/cc-pVTZ methods.
通过气相电子衍射（GED）和量子化学计算（采用不同基组直至aug-cc-pVTZ的B3LYP和MP2近似方法）研究了乙酰丙酮（CH3C(O)CH2C(O)CH3）的互变异构和结构性质。对GED强度的分析表明，在300(5) K时烯醇互变异构体的含量为100(3)%，在671(7) K时烯醇的含量为64(5)%。烯醇互变异构体具有Cs对称性，环呈平面状且具有强不对称氢键。二酮形式具有C2对称性。B3LYP/aug-cc-pVTZ和MP2/cc-pVTZ方法能非常精确地重现两种互变异构形式的实验几何参数。
