A systematic quantum chemistry study on cyclodextrins

AM1 and PM3 modeling of beta-hydroxyethyl ether and alpha-(1-->4)-glucobios e indicated that PM3 is advantageous to AMI in cyclodextrin (CD) chemistry. The conclusion was supported by direct structure optimization of alpha- an d beta-CD with AMI and PM3, in which AM1 gave badly distorted geometries du e to unreasonable hydrogen bonding, whereas PM3 reproduced the crystalline structures rather well. Ab initio calculation was for the first time perfor med on CD, demonstrating the feasibility of this method for future studies concerning CD chemistry. The results also provided valuable insights into t he driving forces in CD molecular recognition.