Perfluorination of Aromatic Compounds Reinforce Their van der Waals Interactions with Rare Gases: The Rotational Spectrum of Pentafluoropyridine-Ne

Abstract

The rotational spectrum of the pentafluoropyridine-Ne complex, generated in a supersonic jet, has been investigated using chirped-pulse microwave Fourier transform spectroscopy in the 2–8 GHz range. The spectra of the 20Ne and 22Ne species have been observed, and the rotational constants have been used to determine the structure of the complex. This structure, and those of the previously experimentally studied complexes benzene-Ne and pyridine-Ne, are an excellent benchmark for the theoretical calculations on these adducts. These complexes and hexafluorobenzene-Ne have been investigated at the CCSD/6-311++G(2d,p) level. The calculations reproduce the experimental structures well and show how the van der Waals complexes are stronger for the perfluorinated compound.

Probing intra- and inter-molecular interactions through rotational spectroscopy: The case of the odorant 2′-aminoacetophenone and its 1:1 water and neon complexes

“…The distance of neon from the ring plane, given by the cs coordinate in the PAS of 2AA, is 3.2569(5) Å-a value smaller than those determined for the complexes of other planar compounds such as benzene 3.408 Å, 50 2,5-dihydrofuran 3.305 Å, 51 and pentafluoropyridine 3.277 Å. 13 The nuclear quadrupole coupling constants provide additional independent information on the molecular geometry of the complexes. We see that the χ cc component of 2AA and 2AA⋅W are equal within the standard errors quoted, and that by rotating the nuclear quadrupole tensor of 2AA by 10.5 ○ around the c axis, we can reproduce the values of 2AA⋅W, achieving χ aa = 1.24 and χ bb = 2.56 MHz.…”

“…The acetyl and amino groups can be involved in hydrogen bond (HB) interactions, acting mainly as proton withdrawing sites, and also as proton donors, whereas the aromatic ring can be involved in different NCIs, such as the π-π stacking, OH-π, NH-π, cation or anion-π interactions, 12 as well as rare gas-π interactions. 13 By choosing water and neon as ligands, we investigate the intrinsic ability of 2AA to coordinate through both HB and van der Waals interactions.…”

Character of intermolecular vibrations in the benzene–neon complex based on CCSD(T) and SAPT potential energy surfaces

“…Previously, rotationally resolved spectra for the benzene-Ne (BzNe) complex were reported, 8,12,23,[33][34][35][36] but no direct measurement of intermolecular vibrations for the BzNe complex has been conducted by now. The other AromNe complexes such as pyrrole-Ne, pyridine-Ne, pentafluoropyridine-Ne and some others were also studied by different experimental methods, 15,19,20,[37][38][39][40][41][42][43][44][45][46][47][48] including the studies where intermolecular vibrations were measured. The experimental study of the intermolecular vibrations in AromNe complexes is more difficult when compared to the AromRg complexes with heavier Ar.…”