Theoretical study on crown compounds as building blocks of functional molecules I. The relation between the hole size and the number of atoms in the ring of cyclic ethers and amines

Abstract

A systematic investigation of the cyclic ethers and amines was conducted using molecular orbital calculations to assess their possibility as building blocks of novel functional molecules. A method was developed to quantitatively calculate the Free-O and Comp-O radii which correspond to the hole sizes of free and complexed crown compounds. These radii show the linear relationship with the number of atoms in crown ring for both calculated and observed coordinates. On the other hand, the Li-X (XO and N) lengths are not dependent on the number of atoms in the crown ring. While the ΔE stab's of the crown ethers show a clear dependence on the number of the crown ring atoms, the values does not vary significantly among the cyclic amines. The MNDO method gave reasonable results by chance.