Azacalix[7]arene heptamethyl ether: preparation, nanochannel crystal structure, and selective adsorption of carbon dioxide

A [5+2]-fragment coupling approach was applied to prepare azacalix[7]arene heptamethyl ether and gain insight into the solid-state complexation of nitrogen-bridged calixarene analogues. The results revealed that the adsorption capacity of azacalix[7]arene for C[O.sub.2] nearly doubled compared to that of azacalix[6]arene due to the formation of the one-dimensional nanochannel with almost twice the volume of the latter.