Crystallization of a Supramolecular Coassembly of an Atomically Precise Nanoparticle with a Crown Ether

Abstract

We report the crystal structure of a supramolecular coassembly of a red luminescent silver cluster, [Ag29(BDT)12(TPP)4]3– (referred to as Ag29) (BDT, 1,3-benzene dithiol; TPP, triphenyl phosphine), with dibenzo-18-crown-6 (DB18C6). The structure may be viewed as crystallization-induced self-organization of DB18C6 molecules into cage-like hexamers in the interstitial spaces of the lattice of trigonal Ag29 (Ag29T) clusters, which resulted in an anisotropic expansion of the Ag29T lattice along its z-axis. This structure corresponds to a new family of "lattice inclusion" compounds in nanoclusters. Supramolecular forces guide the assembly of the clusters and the crown ethers, which pack into complex hierarchical patterns in their crystal lattice. We identified the effect of such a coassembly on the solid-state luminescence of the cluster. The crystals containing the coassembly were ∼3.5-fold more luminescent than the parent Ag29T crystals. We also used high-resolution electrospray ionization mass spectrometry to get further insights into the nature of the complexation between Ag29 cluster and DB18C6. This study provides a new strategy for designing cluster-assembled functional materials with enhanced properties.