Lu Norman, Tu Wen-Han, Wu Zong-Wei, Wen Yuh-Sheng, Liu Ling-Kang
Institute of Organic and Polymeric Materials, National Taipei University of Technology, Taipei 106, Taiwan.
Acta Crystallogr C. 2010 Jun;66(Pt 6):o289-91. doi: 10.1107/S0108270110014356. Epub 2010 May 12.
As part of a homologous series of novel polyfluorinated bipyridyl (bpy) ligands, the title compound, C(16)H(14)F(6)N(2)O(2), contains the smallest fluorinated group, viz. CF(3). The molecule resides on a crystallographic inversion centre at the mid-point of the pyridine C(ipso)-C(ipso) bond. Therefore, the bpy skeleton lies in an anti conformation to avoid repulsion between the two pyridyl N atoms. Weak intramolecular C-H...N and C-H...O interactions are observed, similar to those in related polyfluorinated bpy-metal complexes. A pi-pi interaction is observed between the bpy rings of adjacent molecules and this is probably a primary driving force in crystallization. Weak intermolecular C-H...N hydrogen bonding is present between one of the CF(3)CH(2)- methylene H atoms and a pyridyl N atom related by translation along the [010] direction, in addition to weak benzyl-type C-H...F interactions to atoms of the terminal CF(3) group. It is of note that the O-CH(2)CF(3) bond is almost perpendicular to the bpy plane.
作为新型多氟联吡啶（bpy）配体同系物的一部分，标题化合物C(16)H(14)F(6)N(2)O(2)含有最小的氟代基团，即CF(3)。分子位于吡啶C（ipso）-C（ipso）键中点的晶体学反演中心上。因此，bpy骨架呈反式构象以避免两个吡啶基N原子之间的排斥。观察到弱的分子内C-H...N和C-H...O相互作用，这与相关的多氟联吡啶-金属配合物中的相互作用类似。在相邻分子的bpy环之间观察到π-π相互作用，这可能是结晶过程中的主要驱动力。除了与末端CF(3)基团的原子存在弱的苄基型C-H...F相互作用外，在CF(3)CH(2)-亚甲基的一个H原子与沿[010]方向平移相关的吡啶基N原子之间还存在弱的分子间C-H...N氢键。值得注意的是，O-CH(2)CF(3)键几乎垂直于bpy平面。
