THEORETICAL-STUDY ON CROWN COMPOUNDS AS BUILDING-BLOCKS OF FUNCTIONALMOLECULES .1. THE RELATION BETWEEN THE HOLE SIZE AND THE NUMBER OF ATOMS IN THE RING OF CYCLIC ETHERS AND AMINES

A systematic investigation of the cyclic ethers and amines was conduct ed 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 corresp ond to the hole sizes of free and complexed crown compounds. These rad ii 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 t he crown ring. While the DELTAE(stab)'s of the crown ethers show a cle ar dependence on the number of the crown ring atoms, the values does n ot vary significantly among the cyclic amines. The MNDO method gave re asonable results by chance.