Nonstatistical assembly of multicomponent [Pd2ABCD] cages

Abstract

Self-assembled hosts, inspired by biological receptors and catalysts, show potential for sustainable synthesis, energy conversion and medicine. Implementing multiple functionalities in the form of distinguishable building blocks, however, is difficult without risking narcissistic self-sorting or statistical mess. Here, we report a systematic series of integratively self-assembled heteroleptic cages in which two square-planar PdII cations are bridged by four different bis-pyridyl ligands A, B, C and D via synergistic effects to exclusively form a single isomer — the lantern-shaped cage [Pd2ABCD]. This self-sorting goal — forming just one out of 55 possible structures — is reached under full thermodynamic control and can be realized progressively (by combining progenitors such as [Pd2A2C2] with [Pd2B2D2]), directly from ligands and PdII cations, or by mixing all four corresponding homoleptic cages. The rational design of complex multicomponent assemblies that enables the incorporation of chemical moieties in a modular approach will advance their potential applications in functional nanosystems.