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Cold Snapshot of a Molecular Rotary Motor Captured by High‐Resolution Rotational Spectroscopy
Author(s) -
Domingos Sérgio R.,
Cnossen Arjen,
Buma Wybren J.,
Browne Wesley R.,
Feringa Ben L.,
Schnell Melanie
Publication year - 2017
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201704221
Subject(s) - rotational spectroscopy , spectroscopy , microwave , rotational transition , dissociation (chemistry) , molecular spectroscopy , rotational–vibrational spectroscopy , molecular motor , chemistry , fourier transform spectroscopy , ground state , molecule , molecular physics , nuclear magnetic resonance , atomic physics , materials science , physics , angular momentum , nanotechnology , organic chemistry , quantum mechanics
We present the first high‐resolution rotational spectrum of an artificial molecular rotary motor. By combining chirped‐pulse Fourier transform microwave spectroscopy and supersonic expansions, we captured the vibronic ground‐state conformation of a second‐generation motor based on chiral, overcrowded alkenes. The rotational constants were accurately determined by fitting more than 200 rotational transitions in the 2–4 GHz frequency range. Evidence for dissociation products allowed for the unambiguous identification and characterization of the isolated motor components. Experiment and complementary quantum‐chemical calculations provide accurate geometrical parameters for the C 27 H 20 molecular motor, the largest molecule investigated by high‐resolution microwave spectroscopy to date.