The molecular structure of N-fluorobis(trifluoromethanesulfonyl)imide, NF(SO<sub>2</sub>CF<sub>3</sub>)<sub>2</sub>, as studied in the gas phase by electron diffraction restrained by ab initio calculations
作者:Drahomír Hnyk、Paul T. Brain、David W. H. Rankin、Heather E. Robertson、Bruce A. Smart、R. Eric Banks、Vincent Murtagh
DOI:10.1039/b612318j
日期:——
The structure of N-fluorobis(trifluoromethylsulfonyl)imide, prepared by a relatively safe and easy method, has been determined by gas-phase electron diffraction (GED), employing the SARACEN method, with flexible restraints based on the MP2/6-311G* structure, and by X-ray crystallography at 150 K. The strongly electron-withdrawing CF3 and SO2CF3 groups make the C–S and N–S distances long, averaging 187.7(3) and 171.7(3) pm, respectively, in the gas phase. The gas consists of two conformers, one (75%) with a CF3 group on each side of the SNS plane, one anti-periplanar and one syn-periplanar to the further N–S bond (ap, sp), and the other with both CF3 groups on the same side, i.e. denoted ap, ap. These conformers have very different SNS angles, 126.9(9)° and 117.1(17)° respectively. In the crystal all molecules have the ap, sp conformation, with parameters similar to those found for this conformer in the gas phase.
通过气相电子衍射 (GED),采用基于 MP2/6-311G* 结构的灵活约束的 SARACEN 方法,以及在 150 K 温度下的 X 射线晶体学,确定了用相对安全和简便的方法制备的 N-氟双(三氟甲基磺酰基)亚胺的结构。强吸电子的 CF3 和 SO2CF3 基团使得 C-S 和 N-S 间距较长,在气相中的平均值分别为 187.7(3) 和 171.7(3) pm。气体由两种构象组成,一种(75%)在 SNS 平面的两侧各有一个 CF3 基团,一个反全平面,一个同全平面,与进一步的 N-S 键(ap,sp)平行;另一种在同一侧有两个 CF3 基团,即 ap,ap。这两种构象的 SNS 角截然不同,分别为 126.9(9)° 和 117.1(17)°。在晶体中,所有分子都具有 ap, sp 构象,其参数与气相中该构象的参数相似。