School of Chemistry, University of Bristol, Bristol, BS8 1TS, UK.
Phys Chem Chem Phys. 2011 Dec 14;13(46):20736-44. doi: 10.1039/c1cp21854a. Epub 2011 Oct 14.
The rotational spectra of CF(3)I···NH(3) and CF(3)I···N(CH(3))(3) are measured between 6.7 and 18 GHz using a chirped-pulse Fourier transform microwave spectrometer. Transitions in each spectrum are assigned to A and E species associated with ground and excited internal rotor states respectively. Rotational constants, B(0), centrifugal distortion constants, D(J), D(Jm), D(JKm), nuclear quadrupole coupling constants of the (14)N and (127)I atoms, χ(aa)(N) and χ(aa)(I), are determined for each complex. D(JK) is additionally determined for CF(3)I···NH(3). Results are presented for both (14)N and (15)N-substituted isotopologues. All data are consistent with C(3v) symmetric top structures for both complexes. The nuclear quadrupole coupling constants of iodine are determined to be -2230.030(83) MHz and -2241.61(17) MHz in CF(3)I···(14)NH(3) and CF(3)I···(14)N(CH(3))(3) respectively. The data are interpreted through a model that accounts for the internal dynamics of the complexes in order to determine the length of the halogen bond between the iodine and nitrogen atoms, r(N···I). Values of r(N···I) are thus determined to lie in the ranges 3.054 Å > r(N···I) > 3.034 Å and 2.790 Å > r(N···I) > 2.769 Å for CF(3)I···NH(3) and CF(3)I···N(CH(3))(3) respectively.
使用啁啾脉冲傅里叶变换微波光谱仪在 6.7 至 18GHz 之间测量了 CF(3)I···NH(3)和 CF(3)I···N(CH(3))(3)的旋转光谱。每个光谱中的跃迁分别分配给与地面和激发内部转子态相关的 A 和 E 物种。为每个配合物确定了旋转常数 B(0)、离心畸变常数 D(J)、D(Jm)、D(JKm)、(14)N 和 (127)I 原子的核四极耦合常数 χ(aa)(N)和 χ(aa)(I)。此外，还确定了 CF(3)I···NH(3)的 D(JK)。结果同时给出了(14)N 和 (15)N 取代同位素。所有数据均与两种配合物的 C(3v)对称顶部结构一致。碘的核四极耦合常数分别确定为 CF(3)I···(14)NH(3)中的-2230.030(83)MHz 和-2241.61(17)MHz，以及 CF(3)I···(14)N(CH(3))(3)。通过考虑配合物内部动力学的模型对数据进行解释，以确定碘原子和氮原子之间的卤键长度 r(N···I)。因此，r(N···I)的值分别确定为 3.054Å> r(N···I)>3.034Å和 2.790Å> r(N···I)>2.769Å，用于 CF(3)I···NH(3)和 CF(3)I···N(CH(3))(3)。
