78141-83-0Relevant academic research and scientific papers
Coalescence phenomena in the NMR spectra of some cycloheptatrienes
Zwaard, A. W.,Smits, H. J. E.,Kloosterziel, H.
, p. 187 - 191 (2007/10/02)
Coalescence phenomena have been observed in the NMR spectra of a variety of 7-substituted 1,3,5-cycloheptatrienes upon varying temperature and/or solvent.Using two different methods, the energy of activation of the process responsible for coalescence has been determined.Within a group of structurally similar para-substituted phenyl sulphides a linear relation has been found between the energy of activation and the acidity constant of the corresponding benzenethiol, suggesting the occurrence of ion pairs.The relatively low energy of activation for the phenyl sulphides, when compared with the values of the phenyl sulphones, may rewsult from the structure of the intermediate ion pairs.In addition to the above, a digfferent exchange process between cycloheptatrienyl sulphides and tropylium salt via sulphonium ions has been observed.
Some stable substituted cycloheptatrienyl carbanions
Zwaard, A. W.,Kloosterziel, H.
, p. 126 - 128 (2007/10/02)
The reaction of some 7-substituted cycloheptatrienes with KNH2 in liquid ammonia is described.In several cases stable carbanions are formed.Their NMR spectra are consistent with a non-planar pentadienyl-like structure.A comparison of the 1H-NMR spectra of 10 and 11 shows the paratropic character of the cycloheptatrienyl anions.
