CEQUINOR (UNLP-CONICET), Departamento de Química, Facultad de Ciencias Exactas, Universidad Nacional de La Plata , 47 esq. 115, 1900 La Plata, República Argentina.
J Phys Chem A. 2014 Mar 6;118(9):1721-9. doi: 10.1021/jp4127732. Epub 2014 Feb 21.
The vapor of the new compound 1,1-dicyano-2-chloro-2,2-difluoroethyl chlorodifluoroacetate, CClF2C(O)OC(CN)2CClF2 and of the known 1,1-dicyano-2,2,2-trifluoroethyl trifluoroacetate, CF3C(O)OC(CN)2CF3, were investigated using vibrational spectroscopy tools. The existence of rotational isomerism was confirmed for CClF2C(O)OC(CN)2CClF2 when the matrix isolated compound was examined in combination with the computational results applying quantum chemical models. From the four conformers gauche-syn-gauche, gauche-syn-anti, syn-syn-anti, syn-syn-gauche (the used nomenclature is with respect to the ϕ(ClC-C(O)), ϕ((O)C-OC), and ϕ(OC-CCl) torsion angles, respectively) predicted for CClF2C(O)OC(CN)2CClF2 the first two forms can be evidenced using Ar-matrix IR spectroscopy, with the first one being the most abundant at room temperature. On the other side, the results obtained for CF3C(O)OC(CN)2CF3 reveals the existence of only one syn-syn-anti form. CClF2C(O)OC(CN)2CClF2 melts at -40 °C and its vapor pressure was fitted by the equation ln p = -4732.6 (1/T) + 10.75 (p [Atm], T [K]) in the range -20 to 20 °C. Its extrapolated boiling point is 167 °C. The first ionization potentials occur for CClF2C(O)OC(CN)2CClF2 and CF3C(O)OC(CN)2CF3 at 12.13 and 12.43 eV, respectively, and were attributed to the ejection of electrons formally located at the carbonylic oxygen lone-pair electrons (nO). The proposed interpretation of the photoelectron spectrum is consistent with related molecules reported previously, and also with the prediction of Outer Valence Green's Functions (OVGF).
新型化合物 1,1-二氰基-2-氯-2,2-二氟乙基氯二氟代乙酸酯，CClF2C(O)OC(CN)2CClF2 和已知的 1,1-二氰基-2,2,2-三氟乙基三氟代乙酸酯，CF3C(O)OC(CN)2CF3 的蒸气，使用振动光谱工具进行了研究。当在基质中隔离化合物与应用量子化学模型的计算结果一起检查时，确认了 CClF2C(O)OC(CN)2CClF2 存在旋转异构现象。从 CClF2C(O)OC(CN)2CClF2 预测的四个构象 gauche-syn-gauche、gauche-syn-anti、syn-syn-anti、syn-syn-gauche（所用的命名法是相对于 ϕ(ClC-C(O))、ϕ((O)C-OC) 和 ϕ(OC-CCl) 扭转角）中，可以使用 Ar 基质 IR 光谱证明前两种形式的存在，其中第一种在室温下最丰富。另一方面，对于 CF3C(O)OC(CN)2CF3 的结果表明只存在一种 syn-syn-anti 形式。CClF2C(O)OC(CN)2CClF2 在-40°C 下熔化，其蒸气压在-20 至 20°C 范围内通过方程 ln p = -4732.6 (1/T) + 10.75 (p [Atm], T [K]) 拟合。其外推沸点为 167°C。CClF2C(O)OC(CN)2CClF2 和 CF3C(O)OC(CN)2CF3 的第一电离势分别为 12.13 和 12.43 eV，归因于电子的逐出，电子形式上位于羰基氧孤对电子（nO）上。光电子能谱的提议解释与以前报道的相关分子一致，也与外价格林函数（OVGF）的预测一致。
