Microwave Spectra and Structure of Ar–1,3-Difluorobenzene
Microwave Spectra and Structure of Ar–1,3-Difluorobenzene
复制标题
Ar-1,3-二氟苯的微波光谱和结构
DOI：
10.1021/acs.jpca.8b05282
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Grubbs, G. S.
中科院分区：
文献类型：
--
作者：
Marshall, Frank E.;Dorris, Rachel;Peebles, Sean A.;Peebles, Rebecca A.;Grubbs, G. S.
报道了二聚体Ar-1，3-二氟苯在2-18 GHz的微波光谱。利用啁啾脉冲傅里叶变换微波(CP-FTMW)光谱仪观测到了这一光谱，该光谱仪最近被扩展到包括电磁光谱的2-6 GHz区域。报告了升级后的光谱仪的详细信息。观察到母体二聚体光谱发生了87个跃迁，这与由FA、B和C组成的半刚性转动哈密顿量以及四个四次离心扭曲常数相吻合。利用7-9 GHz和9-11 GHz较小的啁啾范围，分别为190万和373万个平均频率，辅助了对自然丰度13C物种的观测。~(13)C同位素的归属允许确定碳原子的Kraitchman坐标以及络合物的惯性拟合。量子化学结构预测Ar到单体的质心距离为3.48Ar，而实验结构分析得出的结果为3.564(1)Ar。这项新的研究表明，在氟化苯-Ar二聚体中，当氟被更多的碳原子分开时，Ar环的中心距离减小。
The microwave spectrum of the dimer Ar–1,3-difluorobenzene from 2 to 18 GHz is reported. The spectrum has been observed using a chirped-pulse Fourier transform microwave (CP-FTMW) spectrometer that has recently been expanded to include the 2–6 GHz region of the electromagnetic spectrum. Details of this upgraded spectrometer are reported. Eighty-seven transitions were observed for the parent dimer spectrum, which was adequately fit to a semirigid rotational Hamiltonian consisting ofA,B, andCas well as four quartic centrifugal distortion constants. Observations of13C species in natural abundance were aided by utilizing smaller chirp ranges of 7–9 and 9–11 GHz for 1.9 million and 3.73 million averages, respectively. Assignment of13C isotopologues allowed for determination of the Kraitchman coordinates of the carbon atoms as well as inertial fits of the complex. The quantum-chemical structure predicts an Ar to monomer center of mass distance of 3.48 Å, compared with 3.564(1) Å determined from experimental structural analysis. This new study indicates that in fluorinated benzene–Ar dimers, when the fluorines are separated by more carbon atoms, the Ar–ring center distance decreases.