A Modular Approach to Inorganic Phosphazane Macrocycles

Abstract

Inorganic macrocycles, based on non‐carbon backbones, present exciting synthetic challenges in the systematic assembly of inorganic molecules, as well as new avenues in host–guest and supramolecular chemistry. Here we demonstrate a new high‐yielding modular approach to a broad range of trimeric and hexameric S‐ and Se‐bridged inorganic macrocycles based on cyclophosphazane frameworks, using the building blocks [S=(H)P(μ‐NR)]2. The method involves the in situ generation of the key intermediate [Eurn:x-wiley:14337851:media:anie201702558:anie201702558-math-0001 (Surn:x-wiley:14337851:media:anie201702558:anie201702558-math-0002 )P(μ‐NR)]22−(E=S, Se) dianion, which can be reacted with electrophilic [ClP(μ‐NR)]2 to give PIII/PV hexameric rings or reacted with I2 to give trimeric PV variants. Important issues which are highlighted in this work are the competitive bridging ability of S versus Se in these systems and the synthesis of the first air‐stable and chiral inorganic macrocycles.