In this aritcle, molecular dynamics imitation leer approach is used to optimize the geometry of N-(oxabutyl-2-ene acid)-2, 3-benzo-10-aza- 1, 4, 7, 13-tetraoxa-cyclopentadeca-2-ene of the lowest energy. The cis- and trans-geometries of N-(oxabutyl-2-ene acid)-2, 3- benzo-10- aza-1, 4, 7, 13-tetraoxa-cyclopentadeca-2-ene were then optimized with calculated, and vibrational frequency analysis was made. The calculated results of the geometry of trans-N-(oxabutyl-2-ene acid)-2, 3-benzo-10-aza-1, 4, 7, 13-tetraoxa-cyclopentadeca-2-ene agreed well with the results of X-ray analysis. The characteristic absorption peaks of the infrared spectrum were assigned to different kinds of bonds in the compound. The data show that trans- N-(oxabutyl-2-ene acid)-2, 3-benzo-10-aza-1, 4, 7, 13-tetraoxa-cyclopentadeca-2-ene has the geometry of horseshoe. The rare earth metal cation can be embedded in a large cavity of the compound, which makes it a good complexing agent.

Key words: CROWN ETHER, MOLECULAR STRUCTURE