C-H BOND ACTIVATION BY COBALT(I) MACROCYCLES - RAPID H/D EXCHANGE BETWEEN MACROCYCLE AND ACETONITRILE SOLVENT

FT-IR and H-1 NMR spectra of CoL+ (L = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene) in CD3CN indicate rapid H/D exchange of the deuterated solvent with the macrocycle amine protons (rate constant (5 +/- 1) X 10(-4) s-1 at (23 +/- 1) degrees-C) and slower exchange with the protons of the imine methyl and the methylene adjacent to the imine carbon atoms (marked with an asterisk in the figure); the process is anomalously rapid for ''simple'' proton transfer and signals reactivity of the metal center toward C-H activation.