TY - JOUR

T1 - The LAM of the Rings

T2 - Large Amplitude Motions in Aromatic Molecules Studied by Microwave Spectroscopy

AU - Nguyen, Ha Vinh Lam

AU - Caminati, Walther

AU - Grabow, Jens Uwe

N1 - Funding Information: Funding: This research was funded by Agence Nationale de la Recherche ANR, grant number ANR-18-CE29-0011 and the Deutsche Forschungsgemeinschaft (DFG), grant number GR1344/4-1, 4-2, 4-3.

PY - 2022/6/20

Y1 - 2022/6/20

N2 - Large amplitude motions (LAMs) form a fundamental phenomenon that demands the development of specific theoretical and Hamiltonian models. In recent years, along with the strong progress in instrumental techniques on high-resolution microwave spectroscopy and computational capacity in quantum chemistry, studies on LAMs have become very diverse. Larger and more complex molecular systems have been taken under investigation, ranging from series of heteroaromatic molecules from five-and six-membered rings to polycyclic-aromatic-hydrocarbon derivatives. Such systems are ideally suited to create families of molecules in which the positions and the number of LAMs can be varied, while the heteroatoms often provide a sufficient dipole moment to the systems to warrant the observation of their rotational spectra. This review will summarize three types of LAMs: internal rotation, inversion tunneling, and ring puckering, which are frequently observed in aromatic five-membered rings such as furan, thiophene, pyrrole, thiazole, and oxazole derivatives, in aromatic six-membered rings such as benzene, pyridine, and pyrimidine derivatives, and larger combined rings such as naphthalene, indole, and indan derivatives. For each molecular class, we will present the representatives and summarize the recent insights on the molecular structure and internal dynamics and how they help to advance the field of quantum mechanics.

AB - Large amplitude motions (LAMs) form a fundamental phenomenon that demands the development of specific theoretical and Hamiltonian models. In recent years, along with the strong progress in instrumental techniques on high-resolution microwave spectroscopy and computational capacity in quantum chemistry, studies on LAMs have become very diverse. Larger and more complex molecular systems have been taken under investigation, ranging from series of heteroaromatic molecules from five-and six-membered rings to polycyclic-aromatic-hydrocarbon derivatives. Such systems are ideally suited to create families of molecules in which the positions and the number of LAMs can be varied, while the heteroatoms often provide a sufficient dipole moment to the systems to warrant the observation of their rotational spectra. This review will summarize three types of LAMs: internal rotation, inversion tunneling, and ring puckering, which are frequently observed in aromatic five-membered rings such as furan, thiophene, pyrrole, thiazole, and oxazole derivatives, in aromatic six-membered rings such as benzene, pyridine, and pyrimidine derivatives, and larger combined rings such as naphthalene, indole, and indan derivatives. For each molecular class, we will present the representatives and summarize the recent insights on the molecular structure and internal dynamics and how they help to advance the field of quantum mechanics.

KW - aromatic rings

KW - coupled large amplitude motions

KW - internal rotation

KW - inversion tunneling

KW - rotational spectroscopy

UR - http://www.scopus.com/inward/record.url?scp=85132891843&partnerID=8YFLogxK

U2 - 10.3390/molecules27123948

DO - 10.3390/molecules27123948

M3 - Review article

C2 - 35745072

AN - SCOPUS:85132891843

VL - 27

JO - MOLECULES

JF - MOLECULES

SN - 1420-3049

IS - 12

M1 - 3948

ER -