Cavity ring-down spectroscopy of the torsional motions of 1,4-bis(phenylethynyl)benzene.
The torsional motions of jet-cooled 1,4-bis(phenylethynyl)benzene (BPEB), a prototype molecular wire, were studied using cavity ring-down spectroscopy in the first UV absorption band (316-321 nm). The torsional spectrum of 1,4-bis(phenylethynyl)-2,3,5,6-tetradeuteriobenzene was also recorded in the gas phase. Both spectra were successfully simulated using simple cosine potentials to describe the torsional motions. The ground-state barrier to rotation was estimated to be 220-235 cm(-1), which is similar to that of diphenylacetylene (tolane). Complementary DFT calculations were found to overestimate the torsional barrier.
Greaves
Stuart J
SJ
University of Durham, Department of Chemistry, South Road, Durham DH1 3LE, UK.
Flynn
Emma L
EL
Futcher
Emma L
EL
Wrede
Eckart
E
Lydon
Donocadh P
DP
Low
Paul J
PJ
Rutter
Simon R
SR
Beeby
Andrew
A