Host-Guest Complexation of Endohedral Metallofullerene with Azacrown Ether and Its Application

摘要

Complexation of endohedral metallofullerene La@C_(82)-A(1)with macrocyclic compounds,such as 1,4,7,10,13,16-hexaazacyclooctadecane(2),1,4,7,10,13,16-hexamethyl-1,4,7,10,13,16-hexaazacy-clooctadecane(3),mono-aza-18-crown-6 ether(4),18-crown-6 ether(5),and p-tert-butylcalix[n]arenes(n = 4-8,6-10),for the first time is examined.Among them,1 forms a complex with azacrown ethers 2-4 while accompanying the electron transfer between them.This is characteristic of endohedral metallofullerene and caused by its low reduction potential.Activation energies,DELTA G_(et),for the electron transfer from 2-4 to 1 are 4.6,2.8,and 11 kcal/mol,respectively.These small DELTA G_(et)values indicate that the electron transfer from the azacrown ethers to 1 is facile in the ground state.Furthermore,the selective isolation of lanthanum endohedral metallofullerenes from the extracts of soot is accomplished by utilizing the Complexation of 1 with 2.