Fourier transform microwave spectroscopy and molecular structure of the 1,1-difluoroethylene-hydrogen fluoride complex.
Fourier transform microwave spectroscopy and molecular structure of the 1,1-difluoroethylene-hydrogen fluoride complex.
复制标题
1,1-二氟乙烯-氟化氢络合物的傅里叶变换微波光谱和分子结构。
DOI：
--
复制
发表时间：
2009
影响因子：
4.4
通讯作者：
Daniel W. McCune
中科院分区：
文献类型：
--
作者：
H. Leung;M. Marshall;T. Drake;Tadeuz Pudlik;N. Savji;Daniel W. McCune
获得了1，1-二氟乙烯与氟化氢形成的络合物的7-21 GHz的傅里叶变换微波旋转谱，其中包括正常的同位异构体和在自然丰度中得到的两个单取代的(13)C物种。还获得了用氟化氢形成的类似的三种物种的光谱。对光谱的分析提供了旋转常数和超精细常数，结合来自类似络合物1，1-二氟乙烯-乙炔的信息，确定了CH(2)Cf(2)-HF的结构。这种结构类似于从氟乙烯-HF中获得的结构[G.C.Cole和A.C.Legon，Chem.太棒了。让我们来吧。400,419(2004)]，在HF给体和1，1-二氟乙烯上的F原子受体之间存在初级氢键相互作用，而在HF分子上的F原子和取代乙烯上氢键F原子的顺式H原子之间发生二次相互作用，并导致氢键偏离线性。1，1-二氟乙烯与质子酸HF、HCl和HCCH的结构比较表明，氢键长度随气相酸强度的降低而增加，而HF与氟乙烯、1，1-二氟乙烯和1，1，2-三氟乙烯的结构比较表明，F原子的亲核性随着氟取代度的增加而降低，但二次作用长度都非常相似。
Fourier transform microwave rotation spectra in the 7-21 GHz region are obtained for the complex formed between 1,1-difluoroethylene and hydrogen fluoride, including the normal isotopomer and two singly substituted (13)C species obtained in natural abundance. Spectra are also obtained for the analogous three species formed using deuterium fluoride. Analysis of the spectra provides rotational and hyperfine constants that are used, in combination with information from the analogous complex, 1,1-difluoroethylene-acetylene, to determine a structure for CH(2)CF(2)-HF. This structure is similar to that obtained for vinyl fluoride-HF [G. C. Cole and A. C. Legon, Chem. Phys. Lett. 400, 419 (2004)] in that a primary, hydrogen bonding interaction exists between the HF donor and a F atom acceptor on the 1,1-difluoroethylene moiety, while a secondary interaction occurs between the F atom on the HF molecule and the H atom cis to the hydrogen-bonded F atom on the substituted ethylene and causes the hydrogen bond to deviate from linearity. A comparison of the structures of 1,1-difluoroethylene complexes with the protic acids HF, HCl, and HCCH demonstrates that the hydrogen bond length increases with decreasing gas-phase acid strength, whereas a comparison of HF complexes with vinyl fluoride, 1,1-difluoroethylene, and 1,1,2-trifluoroethylene indicates that the nucleophilicity of the F atoms decreases with increasing fluorine substitution, but that the secondary interaction length is remarkably similar in all three complexes.