Hierarchical self-assembly of crown ether based metal-carbene cages into multiple stimuli-responsive cross-linked supramolecular metallogel

Abstract

The hierarchical self-assembly (HSA) strategy widely utilized in biological systems has been applied in artificial systems to orchestrate small building blocks into complex functional architectures. The non-interfering interactions glue various building blocks together and produce new species with attractive properties. Herein, we functionalized NHC-based assemblies with orthogonal host-guest interaction to fabricate metal-carbene based supramolecular polymer gel. A series of unique crown etherappended cylinder-like trinuclear Au I hexacarbene assemblies [Au 3 (L) 2 ](PF 6 ) 3 (L=D1-D4, A1-A4) were synthesized from the corresponding trisimidazolium salts H 3 -L(PF 6 ) 3 (L=D1-D4, A1-A4) in which the N-wingtip of the imidazole moieties were substituted with three identical crown ether groups of different sizes (B15C5, B18C6, B21C7, DB24C8). The gold carbene assembly is able to complex six ammonium salts without disrupting the underlying metal-carbene cylinders. In addition, the supramolecular polymer metallogel featuring a multiple-responsiveness can be formed by using [Au 3 (A4) 2 ](PF 6 ) 3 appended with DB24C8 as the core and bisammonium salt as the cross-linker. The case of introducing orthogonal interaction to NHC moiety by N-wingtip substitution demonstrates the feasibility and the power of such strategy to expand the NHC-based supramolecular system and endow them with novel properties. N-heterocyclic carbene, metallogel, crown ether, orthogonal interactionCitation: Zhang ZE, An YY, Zheng B, Chang JP, Han YF. Hierarchical self-assembly of crown ether based metal-carbene cages into multiple stimuli-responsive cross-linked supramolecular metallogel.

Synthesis and Properties of Supramolecular Crops Based on PNZST Antiferroelectric Film

“…e yield is calculated based on the weight of 100 perennial seeds of different varieties, and 90% is converted into the measured yield. Take the average output of 5 points as the average output of the representative area [27]. e calculation method of soybean yield is shown in the following formula:…”

Crown Ether‐Based Supramolecular Polymers: From Synthesis to Self‐Assembly

“…The combination of metal coordination and crown ether‐based host–guest interaction can also be applied to construct crosslinked CSP. [ 70–73 ] As shown in Figure , monomer 54 consisted of crown ether‐bridged two terpyridines groups, the linear CSP 55 was first fabricated by the metal coordination of Zn (II)–terpyridine, and the crosslinked CSP 56 was then constructed by further adding monomer 53 through the crown ether‐based host–guest recognition. [ 71 ] Owing to the dynamic nature of the noncovalent interactions, the reversible conversion of the topological structures between linear CSP to crosslinked CSP can be actualized by regulating the pH of the solution.…”

Construction and Hierarchical Self-Assembly of Multifunctional Coordination Cages with Triangular Metal–Metal-Bonded Units

“…First, trisimidazolium salts a-c featuring three benzo-18-crown-6 (B18C6) or dibenzo-24crown-8 (DB24C8) units were prepared according to the reported procedure. 11 Trisimidazolium salts a-c reacted with K 2 CO 3 and sulfur powder to obtain corresponding ligands L1-L3 appended with three B18C6 or DB24C8 units in 82−88% yield, as depicted in Scheme S1 (see the Supporting Information, SI). Ligands L1-L3 were fully characterized by 1 H, 13 C{ 1 H} nuclear magnetic resonance (NMR) spectroscopy (see the SI, Figures S1−S6).…”