The Selenium-Based Hexameric Macrocycle [(Se)P(-NtBu)_2P(-Se)]_6

摘要

Recently, we have developed logical approaches to a family of phosphorus-nitrogen-based macrocycles of the type [{P(-NR)}2(-Y)]n.[1], [2] The tetrameric, nitrogen-bridged macrocycle [{P(-NtBu)}2(-NH)]4 (Scheme 1 a) is obtained by the condensation of the dimers [ClP(-NtBu)]2 and [(NH2)P(-NtBu)]2 in the presence of Et3N.[3] However, the pentameric homologue is produced exclusively if this reaction is undertaken in the presence of I- ions, resulting in the host-guest complex [{P(-NtBu)}2(-NH)]5I- (Scheme 1 b).[4] The toroidal structures of the tetramer and pentamer and the presence of endo NH functionalities combine the appearance and host-guest characteristics of organic macrocycles such as calixarenes and porphyrins.