Programmable arrangement of metal ions in a cofacially stacked assembly of porphyrinoids toward molecular tags

Abstract

Cofacial assemblies of metalloporphyrinoids represent a fascinating platform for the fabrication of novel functional molecular assemblies based on π–π, d–d, and d–π interactions between components. In this paper, we present a novel synthetic strategy for the programmable arrangement of different metal ions inside a cofacially stacked trimer of porphyrinoids. A combination of two different assemblies was utilized for our purpose: a tetracationic fourfold rotaxane heterodimer between a porphyrin with four alkylammonium chains and a phthalocyanine bearing four peripheral crown ethers, and a stacked assembly between the fourfold rotaxane heterodimer and an additional tetraanionic porphyrin. Three metal ions, namely Cu(II), Ag(II), and Au(III), were arranged inside the cofacially stacked assembly of three porphyrinoids. Moreover, paramagnetic Cu(II) ions were arranged inside a cofacially stacked heterotrimer of porphyrinoids and were precisely programmed, affording the desired spin–spin communications as readable information. These results indicated that the developed strategy is effective for arranging various metal ions in cofacially stacked assemblies of porphyrinoids toward the creation of molecular tags or bar codes.