Three N-benzyl cage guests with two moiety probes for different cucurbit[n]urils (n＝6～8) have been synthesized and characterized by ¹H NMR spectroscopy and ESMS method, and they are N-benzylhexamethylene tetramine bromide (1), N-benzylquinuclidine bromide (2) and N-benzyl-1,4-diazabicyclo[2,2,2]octane bromide (3), and the probes are benzyl and three different small quaternary ammonium cage. Experimental results by using ¹H NMR technique reveal that the cucurbit[6]uril only includes the benzyl moiety of the title guest to form unsymmetrical host-guest complex with a 1∶1 ratio; the cucurbit[7]uril selectively includes the benzyl moiety of 1 and 3, however, selectively includes cage moiety of 2, also to form unsymmetrical host-guest complex with a 1∶1 ratio, the cucurbit[8]uril only includes the benzyl moiety of the title guest to form symmetrical host-guest complex with a 1∶2 ratio.

Key words: N-benzyl cage compound, ¹H NMR spectroscopy, host-guest complex, cucurbituril