Bis(1,2,3,4-tetrahydroisoquinoline-2-ylmethyl) HBr salt (K2) guest has been synthesized from 1,2,3,4- tetrahydroisoquinoline and ethylenedibromide. The self-assembly interaction models of cucurbit[8]uril (Q[8]) with this synthetic guest have been investigated by using 1H NMR technique, single crystal X-ray diffraction determination and theoretic calculation method. The 1H NMR spectral analysis established a basic interaction model in which a self-assembly supramolecular pseudorotaxane with a host∶guest ratio of 1∶1 forms, in which each host selectively includes the aromatic moieties of two guests and both of the aromatic moieties of each guest were included in the two cavities of two hosts. However, the single crystal structure of the Q[8]-K2 inclusion complex showed that a self-assembly pseudorotaxane with a host∶guest ratio of 1∶2 forms, in which each host also selectively includes the two aromatic moieties of two guests. The calculation results based on the crystal structure data showed that, compared to the free guest and host, the inclusion complex in both solution and solid state appeared to favor in energy.

Key words: cucurbit[8]uril, bis(1,2,3,4-tetrahydroisoquinoline-2-ylmethyl), self-assembly interaction mode