Substitution effect and effect of axle's flexibility at (pseudo-)rotaxanes.

ABSTRACT: This study investigates the effect of substitution with different functional groups and of molecular flexibility by changing within the axle from a single C-C bond to a double C=C bond. Therefore, we present static quantum chemical calculations at the dispersion-corrected density functional level (DFT-D3) for several Leigh-type rotaxanes. The calculated crystal structure is in close agreement with the experimental X-ray data. Compared to a stiffer axle, a more flexible one results in a stronger binding by 1-3 kcal/mol. Alterations of the binding energy in the range of 5 kcal/mol could be achieved by substitution with different functional groups. The hydrogen bond geometry between the isophtalic unit and the carbonyl oxygen atoms of the axle exhibited distances in the range of 2.1 to 2.4 Å

SUBMITTER: Malberg F 

PROVIDER: S-EPMC4077404 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature