Preparation of N-(4',6'-Difluoro-2'-Hydroxybenzyl)-Monoaza-15-Crown-5 and X-ray Crystal structure of Potassium Thiocyanate Complex:A Molecular Partition Wall

摘要

Armed monoaza-15-crown-5 having a 4',6'-difluoro-2'-hydroxybenzyl grousp as an additional bidning site (2) ahs been prepared by the mannich reaction of N-methoxyemthylmonoaza-15-crown-5 with 3,5-difluorophenol. The reactive site on 3,5-difluorophenol for the Mannich reaction was predicted by an electrostatic potnetial calcualtion (density functinal calculatino, SVWN/DN~* method). Ligand 2 is interesting, because it has two possible binding sites (phenolic OH group and fluorine atom) in the side arm. An X-ray crystal structure of the potassium thiocyanate complex of ligand 2 revealed that the oxygen atom of the phenolic OH group binds to the potassium cation incorporated in the crown ether ring, and two water molecules are enclosed by two armed crown ethers with the crown ethers forming partition walls.