Internal rotation and barrier height of CCl 3 group in trichloromethylbenzene as studied by gas-phase electron diffraction

Abstract

The molecular structure of gaseous trichloromethylbenzene has been determined from electron diffraction data. An internal rotation of the CCl 3 group around the CC bond was treated as a precession motion. The rotational barrier height of the CCl 3 group is 1.3(6) kJ mol −1, and the minimum of the barrier is at the position such that one of the CCl bonds lies on the phenyl plane. The tilt angle of the C 3v symmetry axis is 4.6(14)° at the potential minimum position and 3.0(8)° at the potential maximum position. The molecular parameters and uncertainties are r g( CC) ring = 1.399(1) A ̊ , r g( CH) = 1.096(6) A ̊ , r g( CC) = 1.531(5) A ̊ , r g( CCl) = 1.784(2) A ̊ and r g( Cl⋯Cl) = 2.885(2) A ̊ , where the r g (CC) ring is the average value in the ring.