The torsional barriers of 2-hydroxy- and 2-fluorobiphenyl: small but measurable.
By making use of a novel diastereotopicity probe, namely C(CF(3))(2)OH, it has been possible to measure by very low temperature (19)F NMR spectroscopy the elusive aryl-aryl rotation barriers of biphenyls bearing an OH or F group in one ortho position. The experimental values (5.4 and 4.4 kcal mol(-1), respectively) are matched by those from ab initio calculations (5.3 and 4.3 kcal mol(-1), respectively).
Mazzanti
Andrea
A
Department of Organic Chemistry A. Mangini, University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy. mazzand@ms.fci.unibo.it
Lunazzi
Lodovico
L
Ruzziconi
Renzo
R
Spizzichino
Sara
S
Schlosser
Manfred
M