Leung Helen O, Marshall Mark D
Department of Chemistry, Amherst College, Amherst, Massachusetts 01002-5000, USA.
J Chem Phys. 2006 Oct 21;125(15):154301. doi: 10.1063/1.2356478.
Fourier transform microwave, rotational spectra in the 6-21 GHz region are obtained for the complex formed between 1,1-difluoroethylene and acetylene, including the normal isotopomer and each singly substituted (13)C species along with complexes derived from commercially available isotopic varieties of acetylene (HCCD, DCCD, and H(13)C(13)CH). Although two possible planar structures are consistent with the rotational constants derived from analysis of the spectra, ab initio calculations, as well as chemical intuition, support only one of the two as the structure of the complex. Nuclear quadrupole coupling constants for D-containing species show no evidence of electric field gradient perturbation and are consistent with the structures obtained from inertial data. The primary interaction between the two molecules is a 2.646(11) A hydrogen bond with acetylene as the donor and a 1,1-difluoroethylene fluorine as the acceptor that forms a 122.41(79) degrees C-Fcdots, three dots, centeredH angle. A secondary interaction between the acetylenic bond and the difluoroethylene hydrogen atom cis to the acceptor fluorine atom causes the hydrogen bond to deviate 53.25(24) degrees from linearity. Structural comparisons with the related complex, 1,1-difluoroethylene-hydrogen chloride [Z. Kisiel et al., J. Chem. Soc., Faraday Trans. 88, 3385 (1992)], suggest that the hydrogen bond in the acetylene complex is weaker, whereas comparisons with vinyl fluoride-acetylene [G. C. Cole and A. C. Legon, Chem. Phys. Lett. 369, 31 (2003)] indicate that the fluorine atoms in 1,1-difluoroethylene are less basic than the one in vinyl fluoride.
获得了1,1 - 二氟乙烯与乙炔形成的配合物在6 - 21 GHz区域的傅里叶变换微波转动光谱，包括正常同位素异构体和每个单取代的(13)C物种，以及由市售乙炔同位素变体（HCCD、DCCD和H(13)C(13)CH）衍生的配合物。尽管两种可能的平面结构与从光谱分析得出的转动常数一致，但从头算计算以及化学直觉仅支持这两种结构中的一种作为配合物的结构。含D物种的核四极耦合常数没有显示出电场梯度扰动的迹象，并且与从惯性数据获得的结构一致。两个分子之间的主要相互作用是一个2.646(11) Å的氢键，其中乙炔作为供体，1,1 - 二氟乙烯的氟原子作为受体，形成了一个122.41(79)°的C - F···H角。炔键与受体氟原子顺式的二氟乙烯氢原子之间的二级相互作用导致氢键从线性偏离53.25(24)°。与相关配合物1,1 - 二氟乙烯 - 氯化氢[Z. Kisiel等人，《化学学会杂志，法拉第汇刊》88, 3385 (1992)]的结构比较表明，乙炔配合物中的氢键较弱，而与氟乙烯 - 乙炔[G. C. Cole和A. C. Legon，《化学物理通讯》369, 31 (2003)]的比较表明，1,1 - 二氟乙烯中的氟原子碱性比氟乙烯中的氟原子弱。
