Design of Zn-, Cu-, and Fe-Coordination Complexes Confined in a Self-Assembled Nanocage

Abstract

The encapsulation of coordination complexes in a tetragonal prismatic nanocage (1·(BAr F )8 ) built from Zn-porphyrin and macrocyclic Pd-clip-based synthons is described. The functional duality of the guest ligand L 1 allows for its encapsulation inside the cage 1·(BAr F )8 , along with the simultaneous coordination of ZnII, CuII, or FeIII metal ions. Remarkably, the coordination chemistry inside the host–guest adduct L 1 ⊂1·(BAr F )8 occurs in both solution solution and solid state. The resulting confined metallocomplexes have been characterized by means of UV-vis, ESI-HRMS, NMR, and EPR techniques. Furthermore, the emission of the Zn-porphyrin fluorophores of 1·(BAr F )8 is strongly quenched by the encapsulation of paramagnetic complexes, representing a remarkable example of guest-dependent tuning of the host fluorescence.

Cavity-based applications of metallo-supramolecular coordination cages (MSCCs)

“…The coordination of strongly anchored ligands to zinc, copper, and iron metal ions, resulted in metallocomplexes entrapped in the cage. 59…”

A bio-inspired imidazole-functionalised copper cage complex

“…14 Costas and Ribas and co-worker recently synthesised Zn-, Cu-and Fe-coordination complexes based on pyridine coordination within a self-assembled nanocage. 15 However, these species have not been reported to be catalytically active for the transformation of organic substrates.…”

Mixed-Ligand Metal–Organic Frameworks and Heteroleptic Coordination Cages as Multifunctional Scaffolds—A Comparison

“…44 In a second study, Zn-centered porphyrin cages allowed the coordinative encapsulation of ligands with further open coordination sites to bind additional metals (Zn, Fe, or Cu) inside the cavity, both in solution and in the solid state. 45 Furthermore, together with Reek, Ribas and Costas encapsulated a Rh catalyst inside a molecular cage by coordination to the Zn porphyrins (Figure 12). 46 The resulting supramolecular catalyst proved to be highly active and enantioselective for hydroformylation of styrene and its derivatives.…”