TY - JOUR

T1 - Switching Aromatic Character by Complexation

T2 - πto π∗ Change Seen in Molecular Rotation Spectra

AU - Wang, Hao

AU - Chen, Junhua

AU - Duan, Chunguo

AU - Xu, Xuefang

AU - Zheng, Yang

AU - Grabow, Jens Uwe

AU - Gou, Qian

AU - Caminati, Walther

N1 - Funding Information: We are grateful for the financial support from the National Natural Science Foundation of China (Grant No. 22073013); Fundamental Research Funds for the Central Universities (Grant No. 2020CDJXZ002); and Graduate Research and Innovation Foundation of Chongqing, China (Grant No. CYB20043).

PY - 2021/6/3

Y1 - 2021/6/3

N2 - A dominating F···π∗aromatic interaction is found to govern the benzaldehyde···tetrafluoromethane complex, as revealed by this rotational spectroscopic investigation. Secondary F···π∗-C=O- and C σ∗CF4···πaromatic interactions also contribute to the stability of the observed isomer. Narrow splittings have been observed in the rotational spectrum originating from a 3-fold internal rotation of CF4 above the aromatic moiety, and a corresponding V3 barrier was determined to be 1.572(14) kJ mol-1. This is the first rotational spectroscopic evidence in the literature implying that the aromatic π∗ antibonding orbital can be activated not only by electron-withdrawing substituents but also by complexation partners containing atoms with high electronegativity, like CF4. The results emphasize the partner molecules' role to modulate the πelectron structure and show a change in the orbital character (πor π∗) when participating in the formation of noncovalent interactions.

AB - A dominating F···π∗aromatic interaction is found to govern the benzaldehyde···tetrafluoromethane complex, as revealed by this rotational spectroscopic investigation. Secondary F···π∗-C=O- and C σ∗CF4···πaromatic interactions also contribute to the stability of the observed isomer. Narrow splittings have been observed in the rotational spectrum originating from a 3-fold internal rotation of CF4 above the aromatic moiety, and a corresponding V3 barrier was determined to be 1.572(14) kJ mol-1. This is the first rotational spectroscopic evidence in the literature implying that the aromatic π∗ antibonding orbital can be activated not only by electron-withdrawing substituents but also by complexation partners containing atoms with high electronegativity, like CF4. The results emphasize the partner molecules' role to modulate the πelectron structure and show a change in the orbital character (πor π∗) when participating in the formation of noncovalent interactions.

UR - http://www.scopus.com/inward/record.url?scp=85107711401&partnerID=8YFLogxK

U2 - 10.1021/acs.jpclett.1c01318

DO - 10.1021/acs.jpclett.1c01318

M3 - Article

C2 - 34032447

AN - SCOPUS:85107711401

VL - 12

SP - 5150

EP - 5155

JO - Journal of Physical Chemistry Letters

JF - Journal of Physical Chemistry Letters

SN - 1948-7185

ER -