MATRIX-ISOLATION AND VIBRATIONAL SPECTROSCOPY OF CARBOCATIONS

It is reported that some unstable species, such as cyclopropylcarbinyl -, cyclooctyl-, 2-butyl- and 7-norbornyl-carbocations, can be prepared in the SbF5 matrix and investigated by IR spectroscopy combined with high level ab initio calculations. Direct measurements of the changes in bond strenghts, i.e. changes of vibrational frequencies (Delta nu/c m(-1)) induced by forming the cationic species, could yield fundamenta l information on the neighboring group effects. Results of systematic investigations along these lines include studies of the complexes of n itriles and ketones with SbF5, allyl and propargyl cations and chloroc arbocations.