ANORMALY OF CL-35 NMR SPIN-LATTICE RELAXATION RATE FOR THE CHLORIDE ANION IN THE CAPSULAR COMPLEX WITH MACROTRICYCLIC QUATERNARY AMMONIUM ION

The inclusion of chloride ion into homemade macrotricyclic tetra-quaternary ammonium cation MQA4+ has been characterized from the measurement of Cl-35 NMR spin-lattice relaxation rate R1. The observed anormaly in the R(=[Cl-]t/[MQA4+]t) dependence of R1 was simulated by a model of the chemical exchange reaction betwen the capsulated Cl- in a intramolecular cavity of MQA4+ and the Cl-outside it. The R1,c for the former is faster than that for the aqueous Cl- complex by about three times. Thus, R1 plays a significant role as a quantitative prove of the types of the local environment around chloride ions in solution.