Supramolecular Coordination Cages Based on N‐Heterocyclic Carbene‐Gold(I) Ligands and Their Precursors: Self‐Assembly, Structural Transformation and Guest‐Binding Properties

Abstract

The incorporation of functional groups into the cavity of discrete supramolecular coordination cages (SCCs) will bring unique functions and applications. Here, three dicarboxylate ligands (H 2 L1Cl, H 2 L2Cl and H 2 L3Cl) containing N-heterocyclic carbene (NHC) precursors as linkers were introduced to construct SCCs by combining with two C 3symmertic (CpZr) 3 (μ 3 -O)(μ 2 -OH) 3 clusters as three-connect vertices, resulted in a series of rugby-like V 2 E 3 (V = vertex, E = edge) type homoleptic cages (SCC-1, SCC-2 and SCC-3). However, V 4 E 6 -type tetrahedral cages (SCC-4 and SCC-5), incorporating six Au-NHC moieties, were obtained when the corresponding NHC-gold(I) functionalized ligands (H 2 L1 Au , H 2 L2 Au ) were applied. For the first time, we present a trackable CpZr-involved cage to cage conversion to generate a heteroleptic V 2 E 3 cage (SCC-6) from two homoleptic cages (SCC-2 and SCC-5) with different geometries of V 2 E 3 and V 4 E 6 . The heteroleptic assembly SCC-6 can also be formed upon a subcomponent displacement strategy. The structural transformation and reassembly processes were detected and monitored by 1 H NMR spectroscopy and electrospray-ionization mass spectrometry. The formation of heteroleptic assembly was further supported by single crystal X-ray diffraction analysis. Moreover, homoleptic cage SCC-2 possesses a trigonal bipyramidal cationic cavity allowing the encapsulation of a series of sulfonate anionic guests.

A mixed-ligand Co(ii) MOF synthesized from a single organic ligand to capture iodine and methyl iodide vapour

“…Therefore, the resulting ligand, 4-imidazol-1-yl-benzoic acid (HIBA), is also a bifunctional heterotopic ligand with diverse coordination abilities. [34][35][36] Third, the ligand contains only one tetrazole group, meaning that the hydrolysate is unique and can reduce the influencing factors during assembly; thus, the ligand facilitates the generation of a pure product. Luckily, a mixed-ligand Co-MOF, namely, Co-IPT-IBA, was successfully constructed via this strategy.…”

Zirconium Metal–Organic Cages: Synthesis and Applications

“…However, the development of mixed-linker, mixed-metal, or mixed-cage strategies can potentially enhance the heterogeneity and complexity of Zr-MOCs, offering interesting properties for multifunctional applications . In addition, the isoreticular expansion approach via longer/extended ligands coupled with stabilizing strategies may produce materials with higher surface areas and enhanced porosity . Furthermore, using flexible ligands may lead to unusual structures due to their versatile conformations and coordination preferences with metal ions/clusters .…”

“…40 In addition, the isoreticular expansion approach via longer/extended ligands coupled with stabilizing strategies may produce materials with higher surface areas and enhanced porosity. 72 Furthermore, using flexible ligands may lead to unusual structures due to their versatile conformations and coordination preferences with metal ions/clusters. 47 The permutation of these potential strategies with different Zr-MOC systems and/or additive functional groups will potentially expand the cage library and tackle other challenging applications needing small discrete active molecules instead of extended networks.…”

Structural Self‐Assembly and Applications of Metal–Organic Molecular Containers with Flexible Backbones

“…[6][7][8][9][10][11] The hosts usually are defined as "metal-organic molecular containers" (MOMCs), because the special cavities of MOMCs could provide a confined space, which may stabilize the binding guest molecules via the hostguest interactions into the inner cavities, and also are regarded as micro-reactors for the enzyme mimetic catalysis of the specific chemical transformations. [12][13][14][15][16][17][18] Theoretically, there are enormous arrangements of the wide choices of metal sites and diverse organic ligands to form the MOMCs with diverse configurations. In order to accurate control the MOMCs structures in desired shape and size, the selfassembly of the MOMCs should be well designed by using the best matching linkers and the metal nodes with optimum thermodynamic and kinetic structures.…”